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21 May 2022 at 01:52
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Bibliography on: Symbiosis


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RJR: Recommended Bibliography 21 May 2022 at 01:52 Created: 


Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2022-05-20

Quach QN, Gardner DR, Clay K, et al (2022)

Phylogenetic Patterns of Swainsonine Presence in Morning Glories.

Frontiers in microbiology, 13:871148.

Endosymbionts play important roles in the life cycles of many macro-organisms. The indolizidine alkaloid swainsonine is produced by heritable fungi that occurs in diverse plant families, such as locoweeds (Fabaceae) and morning glories (Convolvulaceae) plus two species of Malvaceae. Swainsonine is known for its toxic effects on livestock following the ingestion of locoweeds and the potential for pharmaceutical applications. We sampled and tested herbarium seed samples (n = 983) from 244 morning glory species for the presence of swainsonine and built a phylogeny based on available internal transcribed spacer (ITS) sequences of the sampled species. We show that swainsonine occurs only in a single morning glory clade and host species are established on multiple continents. Our results further indicate that this symbiosis developed ∼5 mya and that swainsonine-positive species have larger seeds than their uninfected conspecifics.

RevDate: 2022-05-19

Unzueta-Martínez A, Scanes E, Parker LM, et al (2022)

Microbiomes of the Sydney Rock Oyster are acquired through both vertical and horizontal transmission.

Animal microbiome, 4(1):32.

BACKGROUND: The term holobiont is widely accepted to describe animal hosts and their associated microorganisms. The genomes of all that the holobiont encompasses, are termed the hologenome and it has been proposed as a unit of selection in evolution. To demonstrate that natural selection acts on the hologenome, a significant portion of the associated microbial genomes should be transferred between generations. Using the Sydney Rock Oyster (Saccostrea glomerata) as a model, we tested if the microbes of this broadcast spawning species could be passed down to the next generation by conducting single parent crosses and tracking the microbiome from parent to offspring and throughout early larval stages using 16S rRNA gene amplicon sequencing. From each cross, we sampled adult tissues (mantle, gill, stomach, gonad, eggs or sperm), larvae (D-veliger, umbo, eyed pediveliger, and spat), and the surrounding environment (water and algae feed) for microbial community analysis.

RESULTS: We found that each larval stage has a distinct microbiome that is partially influenced by their parental microbiome, particularly the maternal egg microbiome. We also demonstrate the presence of core microbes that are consistent across all families, persist throughout early life stages (from eggs to spat), and are not detected in the microbiomes of the surrounding environment. In addition to the core microbiomes that span all life cycle stages, there is also evidence of environmentally acquired microbial communities, with earlier larval stages (D-veliger and umbo), more influenced by seawater microbiomes, and later larval stages (eyed pediveliger and spat) dominated by microbial members that are specific to oysters and not detected in the surrounding environment.

CONCLUSION: Our study characterized the succession of oyster larvae microbiomes from gametes to spat and tracked selected members that persisted across multiple life stages. Overall our findings suggest that both horizontal and vertical transmission routes are possible for the complex microbial communities associated with a broadcast spawning marine invertebrate. We demonstrate that not all members of oyster-associated microbiomes are governed by the same ecological dynamics, which is critical for determining what constitutes a hologenome.

RevDate: 2022-05-19

Drury C, Bean NK, Harris CI, et al (2022)

Intrapopulation adaptive variance supports thermal tolerance in a reef-building coral.

Communications biology, 5(1):486.

Coral holobionts are multi-species assemblages, which adds significant complexity to genotype-phenotype connections underlying ecologically important traits like coral bleaching. Small scale heterogeneity in bleaching is ubiquitous in the absence of strong environmental gradients, which provides adaptive variance needed for the long-term persistence of coral reefs. We used RAD-seq, qPCR and LC-MS/MS metabolomics to characterize host genomic variation, symbiont community and biochemical correlates in two bleaching phenotypes of the vertically transmitting coral Montipora capitata. Phenotype was driven by symbiosis state and host genetic variance. We documented 5 gene ontologies that were significantly associated with both the binary bleaching phenotype and symbiont composition, representing functions that confer a phenotype via host-symbiont interactions. We bred these corals and show that symbiont communities were broadly conserved in bulk-crosses, resulting in significantly higher survivorship under temperature stress in juveniles, but not larvae, from tolerant parents. Using a select and re-sequence approach, we document numerous gene ontologies selected by heat stress, some of which (cell signaling, antioxidant activity, pH regulation) have unique selection dynamics in larvae from thermally tolerant parents. These data show that vertically transmitting corals may have an adaptive advantage under climate change if host and symbiont variance interact to influence bleaching phenotype.

RevDate: 2022-05-20
CmpDate: 2022-05-20

Passarge A, Doehlemann G, JC Misas Villamil (2022)

Detection of Apoplastic Protease Inhibitors Using Convolution Activity-Based Protein Profiling.

Methods in molecular biology (Clifton, N.J.), 2447:95-104.

Activity-based protein profiling (ABPP) is a powerful tool in biological chemistry to monitor protein activity using chemical probes that bind covalently and irreversible to active site of enzymes such as proteases. To date, there are three different ways to experimentally use ABPP: comparative, competitive, and convolution ABPP. Here we use and describe the convolution ABPP approach, a method used to detect changes in protease inhibitor abundance in different proteomes. We have applied this method to monitor the activity of Lolium perenne apoplastic cysteine proteases during the interaction with the fungal endophyte Epichloë festucae. We describe the method to isolate apoplastic fluids from infected and uninfected L. perenne ryegrass leaves and the protocol to perform a convolution ABPP experiment. Furthermore, we report how to quantify and analyze fluorescent gels obtained from the ABPP labeling.

RevDate: 2022-05-18
CmpDate: 2022-05-18

Sarkar I, Sen G, Bhattacharyya S, et al (2022)

Inter-cluster competition and resource partitioning may govern the ecology of Frankia.

Archives of microbiology, 204(6):326.

Microbes live in a complex communal ecosystem. The structural complexity of microbial community reflects diversity, functionality, as well as habitat type. Delineation of ecologically important microbial populations along with exploration of their roles in environmental adaptation or host-microbe interaction has a crucial role in modern microbiology. In this scenario, reverse ecology (the use of genomics to study ecology) plays a pivotal role. Since the co-existence of two different genera in one small niche should maintain a strict direct interaction, it will be interesting to utilize the concept of reverse ecology in this scenario. Here, we exploited an 'R' package, the RevEcoR, to resolve the issue of co-existing microbes which are proven to be a crucial tool for identifying the nature of their relationship (competition or complementation) persisting among them. Our target organism here is Frankia, a nitrogen-fixing actinobacterium popular for its genetic and host-specific nature. According to their plant host, Frankia has already been sub-divided into four clusters C-I, C-II, C-III, and C-IV. Our results revealed a strong competing nature of CI Frankia. Among the clusters of Frankia studied, the competition index between C-I and C-III was the largest. The other interesting result was the co-occurrence of C-II and C-IV groups. It was revealed that these two groups follow the theory of resource partitioning in their lifestyle. Metabolic analysis along with their differential transporter machinery validated our hypothesis of resource partitioning among C-II and C-IV groups.

RevDate: 2022-05-20
CmpDate: 2022-05-20

Smith TE, Li Y, Perreau J, et al (2022)

Elucidation of host and symbiont contributions to peptidoglycan metabolism based on comparative genomics of eight aphid subfamilies and their Buchnera.

PLoS genetics, 18(5):e1010195.

Pea aphids (Acyrthosiphon pisum) are insects containing genes of bacterial origin with putative functions in peptidoglycan (PGN) metabolism. Of these, rlpA1-5, amiD, and ldcA are highly expressed in bacteriocytes, specialized aphid cells that harbor the obligate bacterial symbiont Buchnera aphidicola, required for amino acid supplementation of the host's nutrient-poor diet. Despite genome reduction associated with endosymbiosis, pea aphid Buchnera retains genes for the synthesis of PGN while Buchnera of many other aphid species partially or completely lack these genes. To explore the evolution of aphid horizontally-transferred genes (HTGs) and to elucidate how host and symbiont genes contribute to PGN production, we sequenced genomes from four deeply branching lineages, such that paired aphid and Buchnera genomes are now available for 17 species representing eight subfamilies. We identified all host and symbiont genes putatively involved in PGN metabolism. Phylogenetic analyses indicate that each HTG family was present in the aphid shared ancestor, but that each underwent a unique pattern of gene loss or duplication in descendant lineages. While four aphid rlpA gene subfamilies show no relation to symbiont PGN gene repertoire, the loss of aphid amiD and ldcA HTGs coincides with the loss of symbiont PGN metabolism genes. In particular, the coincident loss of host amiD and symbiont murCEF in tribe Aphidini, in contrast to tribe Macrosiphini, suggests either 1) functional linkage between these host and symbiont genes, or 2) Aphidini has lost functional PGN synthesis and other retained PGN pathway genes are non-functional. To test these hypotheses experimentally, we used cell-wall labeling methods involving a d-alanine probe and found that both Macrosiphini and Aphidini retain Buchnera PGN synthesis. Our results imply that compensatory adaptations can preserve PGN synthesis despite the loss of some genes considered essential for this pathway, highlighting the importance of the cell wall in these symbioses.

RevDate: 2022-05-19

Rosani U (2022)

Tracing RNA viruses associated with Nudibranchia gastropods.

PeerJ, 10:e13410 pii:13410.

Background: Nudibranchia is an under-studied taxonomic group of gastropods, including more than 3,000 species with colourful and extravagant body shapes and peculiar predatory and defensive strategies. Although symbiosis with bacteria has been reported, no data are available for the nudibranch microbiome nor regarding viruses possibly associated with these geographically widespread species.

Methods: Based on 47 available RNA sequencing datasets including more than two billion reads of 35 nudibranch species, a meta-transcriptome assembly was constructed. Taxonomic searches with DIAMOND, RNA-dependent-RNA-polymerase identification with palmscan and viral hallmark genes identification by VirSorter2 in combination with CheckV were applied to identify genuine viral genomes, which were then annotated using CAT.

Results: A total of 20 viral genomes were identified as bona fide viruses, among 552 putative viral contigs resembling both RNA viruses of the Negarnaviricota, Pisuviricota, Kitrinoviricota phyla and actively transcribing DNA viruses of the Cossaviricota and Nucleocytoviricota phyla. The 20 commonly identified viruses showed similarity with RNA viruses identified in other RNA-seq experiments and can be putatively associated with bacteria, plant and arthropod hosts by co-occurence analysis. The RNA samples having the highest viral abundances showed a heterogenous and mostly sample-specific distribution of the identified viruses, suggesting that nudibranchs possess diversified and mostly unknown viral communities.

RevDate: 2022-05-19

Chetta P, G Zadra (2021)

Metabolic reprogramming as an emerging mechanism of resistance to endocrine therapies in prostate cancer.

Cancer drug resistance (Alhambra, Calif.), 4(1):143-162.

Prostate cancer (PCa) is the second leading cause of cancer-related death in the US. Androgen receptor (AR) signaling is the driver of both PCa development and progression and, thus, the major target of current in-use therapies. However, despite the survival benefit of second-generation inhibitors of AR signaling in the metastatic setting, resistance mechanisms inevitably occur. Thus, novel strategies are required to circumvent resistance occurrence and thereby to improve PCa survival. Among the key cellular processes that are regulated by androgens, metabolic reprogramming stands out because of its intricate links with cancer cell biology. In this review, we discuss how cancer metabolism and lipid metabolism in particular are regulated by androgens and contribute to the acquisition of resistance to endocrine therapy. We describe the interplay between genetic alterations, metabolic vulnerabilities and castration resistance. Since PCa cells adapt their metabolism to excess nutrient supply to promote cancer progression, we review our current knowledge on the association between diet/obesity and resistance to anti-androgen therapies. We briefly describe the metabolic symbiosis between PCa cells and tumor microenvironment and how this crosstalk might contribute to PCa progression. We discuss how tackling PCa metabolic vulnerabilities represents a potential approach of synthetic lethality to endocrine therapies. Finally, we describe how the continuous advances in analytical technologies and metabolic imaging have led to the identification of potential new prognostic and predictive biomarkers, and non-invasive approaches to monitor therapy response.

RevDate: 2022-05-17

Kawarai S, Taira K, Shimono A, et al (2022)

Author Correction: Seasonal and geographical differences in the ruminal microbial and chloroplast composition of sika deer (Cervus nippon) in Japan.

Scientific reports, 12(1):8219 pii:10.1038/s41598-022-12520-x.

RevDate: 2022-05-19
CmpDate: 2022-05-19

Yoshikawa A, Izumi T, Moritaki T, et al (2022)

Carcinoecium-Forming Sea Anemone Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae) from the Japanese Deep-Sea Floor: A Taxonomical Description with Its Ecological Observations.

The Biological bulletin, 242(2):127-152.

AbstractHere we describe Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae), a new carcinoecium-forming sea anemone from the deep-sea floor of Japan. Stylobates produces a carcinoecium that thinly covers the snail shells inhabited by host hermit crabs Pagurodofleinia doederleini. The new species is distinct from other species by the shape of the marginal sphincter muscle, the distribution of cnidae, the direction of the oral disk, and host association. The species' novelty is supported by the data of its mitochondrial genes 12S, 16S, and COIII and nuclear genes 18S and 28S. Also, we conducted behavioral observation of this new species, focusing on the feeding behavior and interaction with the specific host hermit crab. Our observations suggest that this sea anemone potentially feeds on the suspended particulate organic matter from the water column or the food residuals of hermit crabs. When the host's shell changed, intensive manipulation for transference of S. calcifer sp. nov. was recorded. However, although the hermit crab detached and transferred the sea anemone to the new shell after shell change, the sea anemone did not exhibit active or cooperative participation. Our data suggest that the sea anemone may not produce a carcinoecium synchronously to its host's growth, contrary to the anecdotal assumption about carcinoecium-forming sea anemones. Conversely, the host hermit crab's growth may not depend entirely on the carcinoecium produced by the sea anemone. This study is perhaps the first observation of the behavioral interaction of the rarely studied carcinoecium-forming mutualism in the deep sea.

RevDate: 2022-05-18

Busby PE, Newcombe G, Neat AS, et al (2022)

Facilitating Reforestation Through the Plant Microbiome: Perspectives from the Phyllosphere.

Annual review of phytopathology [Epub ahead of print].

Tree planting and natural regeneration contribute to the ongoing effort to restore Earth's forests. Our review addresses how the plant microbiome can enhance the survival of planted and naturally regenerating seedlings and serve in long-term forest carbon capture and the conservation of biodiversity. We focus on fungal leaf endophytes, ubiquitous defensive symbionts that protect against pathogens. We first show that fungal and oomycetous pathogen richness varies greatly for tree species native to the United States (n = 0-876 known pathogens per US tree species), with nearly half of tree species either without pathogens in these major groups or with unknown pathogens. Endophytes are insurance against the poorly known and changing threat of tree pathogens. Next, we reviewed studies of plant-phyllosphere feedback, but knowledge gaps prevented us from evaluating whether adding conspecific leaf litter to planted seedlings promotes defensive symbiosis, analogous to adding soil to promote positive feedback. Finally, we discuss research priorities for integrating the plant microbiome into efforts to expand Earth's forests. Expected final online publication date for the Annual Review of Phytopathology, Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

RevDate: 2022-05-18

Shao TY, Kakade P, Witchley JN, et al (2022)

Candida albicans oscillating UME6 expression during intestinal colonization primes systemic Th17 protective immunity.

Cell reports, 39(7):110837.

Systemic immunity is stringently regulated by commensal intestinal microbes, including the pathobiont Candida albicans. This fungus utilizes various transcriptional and morphological programs for host adaptation, but how this heterogeneity affects immunogenicity remains uncertain. We show that UME6, a transcriptional regulator of filamentation, is essential for intestinal C. albicans-primed systemic Th17 immunity. UME6 deletion and constitutive overexpression strains are non-immunogenic during commensal colonization, whereas immunogenicity is restored by C. albicans undergoing oscillating UME6 expression linked with β-glucan and mannan production. In turn, intestinal reconstitution with these fungal cell wall components restores protective Th17 immunity to mice colonized with UME6-locked variants. These fungal cell wall ligands and commensal C. albicans stimulate Th17 immunity through multiple host pattern recognition receptors, including Toll-like receptor 2 (TLR2), TLR4, Dectin-1, and Dectin-2, which work synergistically for colonization-induced protection. Thus, dynamic gene expression fluctuations by C. albicans during symbiotic colonization are essential for priming host immunity against disseminated infection.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Chen Y, Pan T, Chai G, et al (2022)

Complete genome of Mycetocola spongiae MSC19T isolated from deep-sea sponge Cacospongia mycofijiensis indicates the adaptation to deep-sea environment and sponge-microbe symbioses.

Marine genomics, 63:100955.

Genome of Mycetocola spongiae MSC19T, a novel marine sponge-associated Actinobacteria isolated from the Mariana Trench sponge Cacospongia mycofijiensis, was sequenced. The genome has one circular chromosome of 3,196,754 bp, with an average GC content of 66.43 mol%, and 2887 coding sequences. Gene annotation shows that M. spongiae MSC19T possesses series of genes related to adaptation to deep-sea environmental stresses including cold shock, heat shock, osmotic stress and oxidative stress. Genes encoding for heavy metal resistance, multidrug resistance and multiple natural product biosynthesis which are crucial for survival in the extreme environment are also detected in the genome. The potentials to synthesize kinds of vitamins and eukaryotic-like proteins indicates the possible nutrient exchange and mutual recognization between M. spongiae MSC19T and its sponge host. The genome provides insights into the stress resistance and ecological fitness of bacterial symbionts in the deep-sea sponge holobionts.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Monroy-Morales E, Dávila-Delgado R, Ayala-Guzmán E, et al (2022)

Visualization of the Crossroads between a Nascent Infection Thread and the First Cell Division Event in Phaseolus vulgaris Nodulation.

International journal of molecular sciences, 23(9):.

The development of a symbiotic nitrogen-fixing nodule in legumes involves infection and organogenesis. Infection begins when rhizobia enter a root hair through an inward structure, the infection thread (IT), which guides the bacteria towards the cortical tissue. Concurrently, organogenesis takes place by inducing cortical cell division (CCD) at the infection site. Genetic analysis showed that both events are well-coordinated; however, the dynamics connecting them remain to be elucidated. To visualize the crossroads between IT and CCD, we benefited from the fact that, in Phaseolus vulgaris nodulation, where the first division occurs in subepidermal cortical cells located underneath the infection site, we traced a Rhizobium etli strain expressing DsRed, the plant cytokinesis marker YFP-PvKNOLLE, a nuclear stain and cell wall auto-fluorescence. We found that the IT exits the root hair to penetrate an underlying subepidermal cortical (S-E) cell when it is concluding cytokinesis.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Buerger P, Vanstone RT, Maire J, et al (2022)

Long-Term Heat Selection of the Coral Endosymbiont Cladocopium C1acro (Symbiodiniaceae) Stabilizes Associated Bacterial Communities.

International journal of molecular sciences, 23(9):.

Heat-tolerant strains of the coral endosymbiont, Cladocopium C1acro (Symbiodiniaceae), have previously been developed via experimental evolution. Here, we examine physiological responses and bacterial community composition (using 16S rRNA gene metabarcoding) in cultures of 10 heat-evolved (SS) and 9 wild-type (WT) strains, which had been exposed for 6 years to 31 °C and 27 °C, respectively. We also examine whether the associated bacterial communities were affected by a three-week reciprocal transplantation to both temperatures. The SS strains had bacterial communities with lower diversities that showed more stability and lower variability when exposed to elevated temperatures compared with the WT strains. Amplicon sequence variants (ASVs) of the bacterial genera Labrenzia, Algiphilus, Hyphobacterium and Roseitalea were significantly more associated with the SS strains compared with the WT strains. WT strains showed higher abundance of ASVs assigned to the genera Fabibacter and Tropicimonas. We hypothesize that these compositional differences in associated bacterial communities between SS and WT strains also contribute to the thermal tolerance of the microalgae. Future research should explore functional potential between bacterial communities using metagenomics to unravel specific genomic adaptations.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Li YH, Yang YY, Wang ZG, et al (2022)

Emerging Function of Ecotype-Specific Splicing in the Recruitment of Commensal Microbiome.

International journal of molecular sciences, 23(9):.

In recent years, host-microbiome interactions in both animals and plants has emerged as a novel research area for studying the relationship between host organisms and their commensal microbial communities. The fitness advantages of this mutualistic interaction can be found in both plant hosts and their associated microbiome, however, the driving forces mediating this beneficial interaction are poorly understood. Alternative splicing (AS), a pivotal post-transcriptional mechanism, has been demonstrated to play a crucial role in plant development and stress responses among diverse plant ecotypes. This natural variation of plants also has an impact on their commensal microbiome. In this article, we review the current progress of plant natural variation on their microbiome community, and discuss knowledge gaps between AS regulation of plants in response to their intimately related microbiota. Through the impact of this article, an avenue could be established to study the biological mechanism of naturally varied splicing isoforms on plant-associated microbiome assembly.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Hatzios S (2022)

Metabolic Adaptation to Oxidative Stress at the Host-Microbe Interface.

FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 36 Suppl 1:.

Bacteria that chronically colonize the host must adapt to various forms of stress in the host environment. The molecular mechanisms bacteria use to sense and respond to these environmental signals are crucial for maintaining symbiotic associations with host cells. My laboratory uses chemical and biological tools to uncover new molecular mechanisms of bacterial adaptation to oxidative stress. In this talk, I will describe our recent discovery of a widely conserved transporter that enables microbial uptake of a diet-derived antioxidant from the host.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Rideb JR, Varghese A, Nguyen T, et al (2022)

Thermal Stress and Antioxidant Activity in Sea Anemones, Exaiptasia pallida.

FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 36 Suppl 1:.

When exposed to stress, coral reefs undergo bleaching, a process in which the host-symbiont relationship is disrupted. Stressors can be environmental including ocean acidification, exposure to ultraviolet radiation, or rising ocean temperatures due to global warming. The sea anemone, Exaiptasia pallida, serves as a model organism of coral reef biology since both species share symbiotic relationships with their algal symbionts and can undergo bleaching resulting in the expulsion of algal symbionts. This is the ultimate phenotypic result of high levels of stress experienced by the coral reef. Stress factors can lead to an increase in free radicals, like reactive oxygen species (ROS), that will adversely alter lipids, proteins, and DNA and trigger bleaching events. Although oxygen free radicals are natural by-products of metabolic processes in most organisms, they are closely regulated through endogenous systems, such as antioxidants like superoxide dismutase (SOD). We hypothesized that as temperatures increase, the levels of SOD activity in the sea anemone will increase over time. We used commercially available E. pallida to establish a 'stock' aquaria to rear anemones under optimal conditions for at least two weeks before use. The stock aquaria were maintained at 28-30% salinity at 22℃ during a 12-hour light/dark period, at a pH of approximately 8.4, with low levels nitrate, nitrite, and ammonia (checked weekly). E. pallida were moved from the stock tank and placed into one of three identical tanks, maintained at increasing temperatures of 22℃ (control), 24℃, and 29℃. We sampled 5 anemones from each tank at two-week intervals for 8 weeks. Seawater was removed by aspiration, anemones were weighed, flash-frozen in liquid nitrogen, and stored at -80℃. We extracted proteins from each sample by homogenization on ice. For each sample, total protein concentrations were established with a Bradford assay and SOD concentration in units of activity was established with a commercially available SOD assay. By observation, the anemones reared at in the higher range of thermal stress appeared smaller and individuals tended to die faster during the trial. E. pallida reared under increased temperatures of 24℃ and 29℃ showed an increase in SOD activity from week 6 to week 8 compared to the control tank at 22℃. These data are based on two replicates and further trials are currently in progress. Our findings describe the outcome of elevated temperature on levels of metabolism and increased levels of superoxide dismutase activity as a byproduct of stress. In addition, disruption of a host-symbiont relationship was suggested by the decrease in size and death of anemones at higher temperatures. Additional evidence is necessary to support our hypothesis and future experiments will focus on increasing the rearing time, increased temperatures, and other antioxidant defenses like xanthine oxidase or cyclooxygenases.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Davison HR, Pilgrim J, Wybouw N, et al (2022)

Genomic diversity across the Rickettsia and 'Candidatus Megaira' genera and proposal of genus status for the Torix group.

Nature communications, 13(1):2630.

Members of the bacterial genus Rickettsia were originally identified as causative agents of vector-borne diseases in mammals. However, many Rickettsia species are arthropod symbionts and close relatives of 'Candidatus Megaira', which are symbiotic associates of microeukaryotes. Here, we clarify the evolutionary relationships between these organisms by assembling 26 genomes of Rickettsia species from understudied groups, including the Torix group, and two genomes of 'Ca. Megaira' from various insects and microeukaryotes. Our analyses of the new genomes, in comparison with previously described ones, indicate that the accessory genome diversity and broad host range of Torix Rickettsia are comparable to those of all other Rickettsia combined. Therefore, the Torix clade may play unrecognized roles in invertebrate biology and physiology. We argue this clade should be given its own genus status, for which we propose the name 'Candidatus Tisiphia'.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Shimura H, Kim H, Matsuzawa A, et al (2022)

Coat protein of partitiviruses isolated from mycorrhizal fungi functions as an RNA silencing suppressor in plants and fungi.

Scientific reports, 12(1):7855.

Orchid seeds depend on colonization by orchid mycorrhizal (OM) fungi for their germination; therefore, the orchids and OM fungi have long maintained a close relationship (e.g., formation of the hyphal mass structure, peloton) during their evolution. In the present study, we isolated new partitiviruses from OM fungi; partitivirus were separately found in different subcultures from the same fungi. Partitiviruses have been believed to lack an RNA silencing suppressor (RSS), which is generally associated with viral pathogenicity, because most partitiviruses isolated so far are latent in both plants and fungi. However, we found that the coat protein (CP) of our partitiviruses indeed had RSS activity, which differed among the virus isolates from OM fungi; one CP showed RSS activity in both plants and fungi, while another CP showed no activity. The family Partitiviridae include viruses isolated from plants and fungi, and it has been suggested that these viruses may occasionally be transmitted between plant and fungal hosts. Given that there are several reports showing that viruses can adapt to nonhost using strong RSS, we here discussed the idea that partitiviruses may be better able to migrate between the orchid and fungus probably through the pelotons formed in the orchid cells, if host RNA silencing is suppressed by partitivirus RSS.

RevDate: 2022-05-17
CmpDate: 2022-05-17

Song L, Pan L, Jiang N, et al (2022)

Effects of endophytic fungi on parasitic process of Taxillus chinensis.

Scientific reports, 12(1):7744.

Taxillus chinensis (DC.) Danser is an extensively used medicinal shrub in the traditional as well as modern systems of medicines. It is a perennial hemiparasitic plant, which is difficult to propagate artificially because of its low parasitic rate. Successful parasitism of parasitic plants is to fuse their tissues and connect their vasculature to the host vasculature building a physiological bridge, which can efficiently withdraw water, sugars and nutrients from their host plants. It is reported that endophytic fungi play an important role in cell wall degradation and fusion, which is the key forming process of the physiological bridge. Therefore, in this study, the endophytic fungi from T. chinensis of different hosts were isolated, and then the organisms that could degrade the main components of the cell walls were screened out using a medium consisting of guaihuol and cellulose degradation capacity. The results showed that five strains were screened out from 72 endophytic fungi of T. chinensis which with high enzyme activities for lignocellulosic degradation. The laccase and cellulase activities of five strains reached their peaks at day 7, and the highest enzyme activities of these two enzymes were found in strain P6, which was 117.66 and 1.66 U/mL, respectively. Manganese peroxidase of strain 4 and lignin peroxidase of strain N6 also reached their peaks at day 7 and were the highest among the 5 strains, with enzyme activities of 11.61 and 6.64 U/mL, respectively. Strains 4, 15, 31, N6 and P6 were identified as Colletotrichum sp., Nigerrospora sphaerica, Exserohilum sp., Diaporthe phaseolorum and Pestalotiopsis sp., respectively, according to their morphological and molecular biology properties. The endophytic fungi may secrete efficient cell wall degradation enzymes, which promote the dissolution and relaxation of the cell wall between T. chinensis and host, thus contributing to the parasitism of T. chinensis.

RevDate: 2022-05-16

Vandegrift MA, RE Taylor-Piliae (2022)

Selecting a theoretical framework for chronic cardiovascular disease self-management among rural dwelling adults.

Applied nursing research : ANR, 65:151585.

A paucity of research has examined the factors and perceptions of self-management among individuals living rurally with chronic cardiovascular disease (CCVD). Exploration of this population is prudent as CCVD continues to be the leading cause of mortality within the United States (US). As the US population ages, increased rates of CCVD and the process of managing the disease will continue to challenge patients and the health care system. Rural dwelling adults are faced with additional complexities to manage a chronic disease, resulting in higher rates of chronic disease as compared to urban dwellers. It is essential for nurses working with adults living with CCVD in rural areas to promote self-management strategies derived from a theoretical perspective. The purpose of this paper is to examine theories and models that facilitate self-management of CCVD among rural dwelling adults. Three established self-management theories and models from psychology and public health were evaluated using Walker and Avant's framework for theory analysis. Social cognitive theory was selected as a best fit for self-management of CCVD among rural dwelling adults, due to the symbiosis of chronic disease, and applicability of ruralness within the triadic reciprocal causation of person-behavior-environment of the model.

RevDate: 2022-05-16

Um S, Lee J, SH Kim (2022)

Lobophorin Producing Endophytic Streptomyces olivaceus JB1 Associated With Maesa japonica (Thunb.) Moritzi & Zoll.

Frontiers in microbiology, 13:881253.

In this study, we focused on endophytes of Maesa japonica (Thunb.) Moritzi & Zoll. and the plant-microbe interaction at metabolite levels. We isolated seven endophytes associated with M. japonica (JB1-7), and focused on Streptomyces olivaceus JB1 because of antibacterial activities of its secondary metabolites. We confirmed lobophorin analogs production from the bacterial strain JB1 by using spectroscopic techniques such as NMR, UV, and LC/Q-TOF-MS. In the LC/MS system, thirteen reported lobophorin analogs and twelve unreported analogs were detected. Among metabolites, lobophorin A was clearly detected in the dried foliar residues of M. japonica which implies that JB1 resides in the host and accumulates its secondary metabolites likely interacting with the plant. Antimicrobial activity tests of the secondary metabolites against undesirable contaminants isolated from the external surface of M. japonica supported the host and microbe mutualistic relationship. In the meantime, lobophorin producing Streptomyces spp. were isolated from marine environments such as marine sediments, algae, corals, and sponges. As lobophorin producing Streptomyces is isolated commonly from marine environments, we conducted a saline water stress tolerance test with JB1 showing saline medium does not accelerate the growth of the bacterium.

RevDate: 2022-05-16

Grossman AS, Escobar CA, Mans EJ, et al (2022)

A Surface Exposed, Two-Domain Lipoprotein Cargo of a Type XI Secretion System Promotes Colonization of Host Intestinal Epithelia Expressing Glycans.

Frontiers in microbiology, 13:800366.

The only known required component of the newly described Type XI secretion system (TXISS) is an outer membrane protein (OMP) of the DUF560 family. TXISSOMPs are broadly distributed across proteobacteria, but properties of the cargo proteins they secrete are largely unexplored. We report biophysical, histochemical, and phenotypic evidence that Xenorhabdus nematophila NilC is surface exposed. Biophysical data and structure predictions indicate that NilC is a two-domain protein with a C-terminal, 8-stranded β-barrel. This structure has been noted as a common feature of TXISS effectors and may be important for interactions with the TXISSOMP. The NilC N-terminal domain is more enigmatic, but our results indicate it is ordered and forms a β-sheet structure, and bioinformatics suggest structural similarities to carbohydrate-binding proteins. X. nematophila NilC and its presumptive TXISSOMP partner NilB are required for colonizing the anterior intestine of Steinernema carpocapsae nematodes: the receptacle of free-living, infective juveniles and the anterior intestinal cecum (AIC) in juveniles and adults. We show that, in adult nematodes, the AIC expresses a Wheat Germ Agglutinin (WGA)-reactive material, indicating the presence of N-acetylglucosamine or N-acetylneuraminic acid sugars on the AIC surface. A role for this material in colonization is supported by the fact that exogenous addition of WGA can inhibit AIC colonization by X. nematophila. Conversely, the addition of exogenous purified NilC increases the frequency with which X. nematophila is observed at the AIC, demonstrating that abundant extracellular NilC can enhance colonization. NilC may facilitate X. nematophila adherence to the nematode intestinal surface by binding to host glycans, it might support X. nematophila nutrition by cleaving sugars from the host surface, or it might help protect X. nematophila from nematode host immunity. Proteomic and metabolomic analyses of wild type X. nematophila compared to those lacking nilB and nilC revealed differences in cell wall and secreted polysaccharide metabolic pathways. Additionally, purified NilC is capable of binding peptidoglycan, suggesting that periplasmic NilC may interact with the bacterial cell wall. Overall, these findings support a model that NilB-regulated surface exposure of NilC mediates interactions between X. nematophila and host surface glycans during colonization. This is a previously unknown function for a TXISS.

RevDate: 2022-05-16

Elhaissoufi W, Ghoulam C, Barakat A, et al (2022)

Phosphate bacterial solubilization: A key rhizosphere driving force enabling higher P use efficiency and crop productivity.

Journal of advanced research, 38:13-28 pii:S2090-1232(21)00167-3.

Background: Increasing crop production to feed a growing population has driven the use of mineral fertilizers to ensure nutrients availability and fertility of agricultural soils. After nitrogen, phosphorus (P) is the second most important nutrient for plant growth and productivity. However, P availability in most agricultural soils is often limited because P strongly binds to soil particles and divalent cations forming insoluble P-complexes. Therefore, there is a constant need to sustainably improve soil P availability. This may include, among other strategies, the application of microbial resources specialized in P cycling, such as phosphate solubilizing bacteria (PSB). This P-mediating bacterial component can improve soil biological fertility and crop production, and should be integrated in well-established formulations to enhance availability and efficiency in use of P. This is of importance to P fertilization, including both organic and mineral P such as rock phosphate (RP) aiming to improve its agronomic efficiency within an integrated crop nutrition system where agronomic profitability of P and PSB can synergistically occur.

Aim of Review: The purpose of this review is to discuss critically the important contribution of PSB to crop P nutrition in concert with P fertilizers, with a specific focus on RP. We also highlight the need for PSB bioformulations being a sustainable approach to enhance P fertilizer use efficiency and crop production.

We first recognize the important contribution of PSB to sustain crop production, which requires a rational approach for both screening and evaluation of PSB enabling an accurate assessment of the bacterial effects both alone and in intertwined interaction with plant roots. Furthermore, we propose new research ideas about the development of microbial bioformulations based on PSB with a particular focus on strains exhibiting synergetic effects with RP.

RevDate: 2022-05-16

Wilta F, Chong ALC, Selvachandran G, et al (2022)

Generalized Susceptible-Exposed-Infectious-Recovered model and its contributing factors for analyzing the death and recovery rates of the COVID-19 pandemic.

Applied soft computing pii:S1568-4946(22)00310-6 [Epub ahead of print].

COVID-19 is a highly contagious disease that has infected over 136 million people worldwide with over 2.9 million deaths as of 11 April 2021. In March 2020, the WHO declared COVID-19 as a pandemic and countries began to implement measures to control the spread of the virus. The spread and the death rates of the virus displayed dramatic differences among countries globally, showing that there are several factors affecting its spread and mortality. By utilizing the cumulative number of cases from John Hopkins University, the recovery rate, death rate, and the number of active, recovered, and death cases were simulated to analyze the trends and patterns within the chosen countries. 10 countries from 3 different case severity categories (high cases, medium cases, and low cases) and 5 continents (Asia, North America, South America, Europe, and Oceania) were studied. A generalized SEIR model which considers control measures such as isolation, and preventive measures such as vaccination is applied in this study. This model is able to capture not only the dynamics between the states, but also the time evolution of the states by using the fourth-order-Runge-Kutta process. This study found no significant patterns in the countries under the same case severity category, suggesting that there are other factors contributing to the pattern in these countries. One of the factors influencing the pattern in each country is the population's age. COVID-19 related deaths were found to be notably higher among older people, indicating that countries comprising of a larger proportion of older age groups have an increased risk of experiencing higher death rates. Tighter governmental control measures led to fewer infections and eventually reduced the number of death cases, while increasing the recovery rate, and early implementations were found to be far more effective in controlling the spread of the virus and produced better outcomes.

RevDate: 2022-05-16

Cho G, Gang GH, Jung HY, et al (2022)

Exploration of Mycobiota in Cypripedium japonicum, an Endangered Species.

Mycobiology, 50(2):142-149 pii:2064409.

Orchids live with mycorrhizal fungi in mutualism. This symbiotic relationship plays an essential role in the overall life cycle of orchids from germination, growth, settlement, and reproduction. Among the 1000 species of the orchid, the Korean lady's slipper, Cypripedium japonicum, is known as an endangered species. Currently, only five natural habitats of the Korean lady's slipper remain in South Korea, and the population of Korean lady's slipper in their natural habitat is not increasing. To prevent extinction, this study was designed to understand the fungal community interacting in the rhizosphere of the Korean lady's slipper living in the native and artificial habitats. In-depth analyses were performed to discover the vital mycorrhizal fungi contributing to habitat expansion and cultivation of the endangered orchid species. Our results suggested that Lycoperdon nigrescens contributed most to the increase in natural habitats and Russula violeipes as a characteristic of successful cultivation. And the fungi that helped L. nigrescens and R. violeipes to fit into the rhizosphere community in Korean lady's slipper native place were Paraboeremia selaginellae and Metarhizium anisopliae, respectively. The findings will contribute to restoring and maintaining the endangered orchid population in natural habitats.

RevDate: 2022-05-16

Gwon JH, Park H, AH Eom (2022)

Mycorrhization of Quercus spp. with Tuber huidongense and T. himalayense Collected in Korea.

Mycobiology, 50(2):104-109 pii:2065717.

Fungi of the genus Tuber are ectomycorrhizal fungi that form a symbiotic relationship mainly with oak and hazel trees. Tuber spp. exhibit a highly selective host plant preference; thus, for cultivation purposes it is important to select an appropriate host plant for successful mycorrhization. In addition, as mycorrhizal characteristics differ according to Tuber spp., it is necessary to understand the differences in mycorrhizae according to the fungal species. Tuber huidongense and Tuber himalayense were recently discovered in Korea; therefore, we used spore suspensions from these two species to inoculate two species of oak trees, Quercus acutissima and Quercus dentata, to compare colonization rates and morphologies of the mycorrhizae. The colonization rates demonstrated that the different Tuber spp. favored different host plant species. In addition, unique morphological and anatomical characteristics were observed for T. huidongense and T. himalayense depending on the host species. These findings can lead to new economically important agricultural activities related to truffle cultivation in Korea.

RevDate: 2022-05-15

Cummins NW, AD Badley (2022)

Could proteasome inhibition improve therapeutic vaccine response in HIV?.

Vaccine pii:S0264-410X(22)00578-3 [Epub ahead of print].

RevDate: 2022-05-15

Matsubara A, Nomura A, T Yamaguchi (2022)


Arerugi = [Allergy], 71(3):191-194.

RevDate: 2022-05-15

Xu L, Wang J, Xiao Y, et al (2022)

Structural insight into chitin perception by chitin elicitor receptor kinase 1 of Oryza sativa.

Journal of integrative plant biology [Epub ahead of print].

Plants have developed innate immune systems to fight against pathogenic fungi by monitoring pathogenic signals known as pathogen-associated molecular patterns (PAMP) and have established endo symbiosis with arbuscular mycorrhizal (AM) fungi through recognition of mycorrhizal (Myc) factors. Chitin elicitor receptor kinase 1 of Oryza sativa subsp. Japonica (OsCERK1) plays a bifunctional role in mediating both chitin-triggered immunity and symbiotic relationships with AM fungi. However, it remains unclear whether OsCERK1 can directly recognize chitin molecules. In this study, we show that OsCERK1 binds to the chitin hexamer ((NAG)6) and tetramer ((NAG)4) directly and determine the crystal structure of the OsCERK1-(NAG)6 complex at 2 Å. The structure shows that one OsCERK1 is associated with one (NAG)6 . Upon recognition, chitin hexamer binds OsCERK1 by interacting with the shallow groove on the surface of LysM2. These structural findings, complemented by mutational analyses, demonstrate that LysM2 is crucial for recognition of both (NAG)6 and (NAG)4 . Altogether, these findings provide structural insights into the ability of OsCERK1 in chitin perception, which will lead to a better understanding of the role of OsCERK1 in mediating both immunity and symbiosis in rice. This article is protected by copyright. All rights reserved.

RevDate: 2022-05-14

Feng J, Lv W, Xu J, et al (2022)

Overlapping Root Architecture and Gene Expression of Nitrogen Transporters for Nitrogen Acquisition of Tomato Plants Colonized with Isolates of Funneliformis mosseae in Hydroponic Production.

Plants (Basel, Switzerland), 11(9): pii:plants11091176.

Understanding the impact of arbuscular mycorrhizal fungi (AMF) upon the nitrogen (N) uptake of tomato (Lycopersicum esculentum L.) plants is crucial for effectively utilizing these beneficial microorganisms in industrial hydroponic tomato production. Yet it remains unknown whether, besides fungal delivery, the AMF also affects N uptake via altered plant root growth or whether, together with changed N transporters expression of hosts, this impact is isolate-specific. We investigated tomato root architecture and the expression of LeAMT1.1, LeAMT1.2, and LeNRT2.3 genes in roots inoculated with five isolates of Funneliformis mosseae, these collected from different geographical locations, under greenhouse conditions with nutritional solution in coconut coir production. Our results revealed that isolate-specific AMF inoculation strongly increased the root biomass, total root length, surface area, and volume. Linear relationships were found between the total root length and N accumulation in plants. Furthermore, expression levels of LeAMT1.1, LeAMT1.2, and LeNRT2.3 were significantly up-regulated by inoculation with F. mosseae with isolate-specific. These results implied N uptake greater than predicted by root growth, and N transporters up-regulated by AMF symbiosis in an isolate-specific manner. Thus, an overlap in root biomass, architecture and expression of N transporters increase N acquisition in tomato plants in the symbiosis.

RevDate: 2022-05-14

Flores-Duarte NJ, Mateos-Naranjo E, Redondo-Gómez S, et al (2022)

Role of Nodulation-Enhancing Rhizobacteria in the Promotion of Medicago sativa Development in Nutrient-Poor Soils.

Plants (Basel, Switzerland), 11(9): pii:plants11091164.

Legumes are usually used as cover crops to improve soil quality due to the biological nitrogen fixation that occurs due to the interaction of legumes and rhizobia. This symbiosis can be used to recover degraded soils using legumes as pioneer plants. In this work, we screened for bacteria that improve the legume-rhizobia interaction in nutrient-poor soils. Fourteen phosphate solubilizer-strains were isolated, showing at least three out of the five tested plant growth promoting properties. Furthermore, cellulase, protease, pectinase, and chitinase activities were detected in three of the isolated strains. Pseudomonas sp. L1, Chryseobacterium soli L2, and Priestia megaterium L3 were selected to inoculate seeds and plants of Medicago sativa using a nutrient-poor soil as substrate under greenhouse conditions. The effects of the three bacteria individually and in consortium showed more vigorous plants with increased numbers of nodules and a higher nitrogen content than non-inoculated plants. Moreover, bacterial inoculation increased plants' antioxidant activities and improved their development in nutrient-poor soils, suggesting an important role in the stress mechanisms of plants. In conclusion, the selected strains are nodulation-enhancing rhizobacteria that improve leguminous plants growth and nodulation in nutrient-poor soils and could be used by sustainable agriculture to promote plants' development in degraded soils.

RevDate: 2022-05-14

Jēkabsone A, Andersone-Ozola U, Karlsons A, et al (2022)

Dependence on Nitrogen Availability and Rhizobial Symbiosis of Different Accessions of Trifolium fragiferum, a Crop Wild Relative Legume Species, as Related to Physiological Traits.

Plants (Basel, Switzerland), 11(9): pii:plants11091141.

Biological nitrogen fixation by legume-rhizobacterial symbiosis in temperate grasslands is an important source of soil nitrogen. The aim of the present study was to characterize the dependence of different accessions of T. fragiferum, a rare crop wild relative legume species, from their native rhizobia as well as additional nitrogen fertilization in controlled conditions. Asymbiotically cultivated, mineral-fertilized T. fragiferum plants gradually showed signs of nitrogen deficiency, appearing as a decrease in leaf chlorophyll concentration, leaf senescence, and a decrease in growth rate. The addition of nitrogen, and the inoculation with native rhizobia, or both treatments significantly prevented the onset of these symptoms, leading to both increase in plant shoot biomass as well as an increase in tissue concentration of N. The actual degree of each type of response was genotype-specific. Accessions showed a relatively similar degree of dependence on nitrogen (70-95% increase in shoot dry mass) but the increase in shoot dry mass by inoculation with native rhizobia ranged from 27 to 85%. In general, there was no correlation between growth stimulation and an increase in tissue N concentration by the treatments. The addition of N or rhizobial inoculant affected mineral nutrition at the level of both macronutrient and micronutrient concentration in different plant parts. In conclusion, native rhizobial strains associated with geographically isolated accessions of T. fragiferum at the northern range of distribution of the species represent a valuable resource for further studies aimed at the identification of salinity-tolerant N2-fixing bacteria for the needs of sustainable agriculture, as well as in a view of understanding ecosystem functioning at the level of plant-microorganism interactions.

RevDate: 2022-05-14

Nascimento LBDS, M Tattini (2022)

Beyond Photoprotection: The Multifarious Roles of Flavonoids in Plant Terrestrialization.

International journal of molecular sciences, 23(9): pii:ijms23095284.

Plants evolved an impressive arsenal of multifunctional specialized metabolites to cope with the novel environmental pressures imposed by the terrestrial habitat when moving from water. Here we examine the multifarious roles of flavonoids in plant terrestrialization. We reason on the environmental drivers, other than the increase in UV-B radiation, that were mostly responsible for the rise of flavonoid metabolism and how flavonoids helped plants in land conquest. We are reasonably based on a nutrient-deficiency hypothesis for the replacement of mycosporine-like amino acids, typical of streptophytic algae, with the flavonoid metabolism during the water-to-land transition. We suggest that flavonoids modulated auxin transport and signaling and promoted the symbiosis between plants and fungi (e.g., arbuscular mycorrhizal, AM), a central event for the conquest of land by plants. AM improved the ability of early plants to take up nutrients and water from highly impoverished soils. We offer evidence that flavonoids equipped early land plants with highly versatile "defense compounds", essential for the new set of abiotic and biotic stressors imposed by the terrestrial environment. We conclude that flavonoids have been multifunctional since the appearance of plants on land, not only acting as UV filters but especially improving both nutrient acquisition and biotic stress defense.

RevDate: 2022-05-14

Parejo S, Cabrera JJ, Jiménez-Leiva A, et al (2022)

Fine-Tuning Modulation of Oxidation-Mediated Posttranslational Control of Bradyrhizobium diazoefficiens FixK2 Transcription Factor.

International journal of molecular sciences, 23(9): pii:ijms23095117.

FixK2 is a CRP/FNR-type transcription factor that plays a central role in a sophisticated regulatory network for the anoxic, microoxic and symbiotic lifestyles of the soybean endosymbiont Bradyrhizobium diazoefficiens. Aside from the balanced expression of the fixK2 gene under microoxic conditions (induced by the two-component regulatory system FixLJ and negatively auto-repressed), FixK2 activity is posttranslationally controlled by proteolysis, and by the oxidation of a singular cysteine residue (C183) near its DNA-binding domain. To simulate the permanent oxidation of FixK2, we replaced C183 for aspartic acid. Purified C183D FixK2 protein showed both low DNA binding and in vitro transcriptional activation from the promoter of the fixNOQP operon, required for respiration under symbiosis. However, in a B. diazoefficiens strain coding for C183D FixK2, expression of a fixNOQP'-'lacZ fusion was similar to that in the wild type, when both strains were grown microoxically. The C183D FixK2 encoding strain also showed a wild-type phenotype in symbiosis with soybeans, and increased fixK2 gene expression levels and FixK2 protein abundance in cells. These two latter observations, together with the global transcriptional profile of the microoxically cultured C183D FixK2 encoding strain, suggest the existence of a finely tuned regulatory strategy to counterbalance the oxidation-mediated inactivation of FixK2 in vivo.

RevDate: 2022-05-13

Ahlawat A, Khan AA, Deshmukh P, et al (2022)

Strain assisted magnetoelectric coupling in ordered nanomagnets of CoFe2O4/SrRuO3/(Pb(Mg1/3Nb2/3)O3-PbTiO3) hetrostructures.

Journal of physics. Condensed matter : an Institute of Physics journal [Epub ahead of print].

We have explored the electric field controlled magnetization in the nanodot CoFe2O4/SrRuO3/PMN-PT heterostructures. Ordered ferromagnetic CFO nanodots (~300 nm lateral dimension) are developed on the PMN-PT substrate (ferroelectric as well as piezoelectric) using a nanostencil-mask pattering method during pulsed laser deposition. The nanostructures reveal electric field induced magnetization reversal in the single domain CFO nanodots through transfer of the piezostrains from the piezoelectric PMN-PT substrate to the CFO. Further, electric field modulated spin structure of CFO nanomagnets is analysed by using X-ray magnetic circular dichroism (XMCD). The XMCD analysis divulge cations (Fe3+/Co2+) redistribution on octahedral and tetrahedral site in the electric field poled CoFe2O4 nanodots, establishing the strain induced magneto-electric coupling effects.The CoFe2O4/SrRuO3/PMN-PT nanodots structure demonstrate multilevel switching of ME coupling coefficient (α) by applying selective positive and negative electric fields in a non-volatile manner. The retention of two stable states of α is illustrated for ~106seconds, which can be employedto store digital datain non-volatile memory devices. Thus the voltage controlled magnetization in the nanodot structures leads a path towards the invention of energy efficient high-density memory devices.

RevDate: 2022-05-13

Shahid M, Ahmed B, Zaidi A, et al (2018)

Toxicity of fungicides to Pisum sativum: a study of oxidative damage, growth suppression, cellular death and morpho-anatomical changes.

RSC advances, 8(67):38483-38498 pii:c8ra03923b.

Considering the fungicidal threat to the sustainable agro-environment, the toxicological impacts of three fungicides, namely kitazin, hexaconazole and carbendazim, on the biological, chemical and morpho-anatomical changes of peas were assessed. Fungicide applications in general caused a slow but gradual reduction in growth, symbiosis and yields of peas, which, however, varied appreciably among species and concentrations of the three fungicides. Of the three fungicides, carbendazim had the most lethal effect, in which it delayed seed germination and also diminished the overall pea growth. Carbendazim at 3000 μg kg-1 maximally reduced the germination, SVI, size of roots and shoots and total dry matter accumulation in roots, shoots and whole plants distinctly by 40%, 84%, 72%, 73%, 68%, 75% and 73% (p ≤ 0.05), respectively. Hexaconazole at 120 μg kg-1 significantly (p ≤ 0.05) declined total chlorophyll, carotenoids, grain yields, grain protein, root P and shoot N by 19%, 28%, 46%, 69%, 48% and 51%, respectively, over the control. The synthesis of stress biomarkers and oxidative stress were increased with increasing dosage rates of fungicides. Proline content in roots, shoots, leaves and grains, MDA, electrolyte leakage and H2O2 of plants grown in soil treated with 288 μg kg-1 kitazin were increased significantly (p ≤ 0.05) by 73%, 52%, 41%, 24%, 59%, 40% and 27%, respectively, relative to the control. Antioxidant defence enzymes were greater in pea foliage. The SEM and CLSM images revealed an obvious alteration in root tips, enhanced cellular damage and cell death when plants were raised under fungicide stress. Also, morpho-anatomical variations in fungicide-treated foliage were visible in the SEM images. Overall, the present study suggests that a careful and secure strategy should be adopted before fungicides are chosen for enhancing pulse production in different agro-climatic regions.

RevDate: 2022-05-13

Kitaeva AB, Gorshkov AP, Kusakin PG, et al (2022)

Tubulin Cytoskeleton Organization in Cells of Determinate Nodules.

Frontiers in plant science, 13:823183.

Plant cell differentiation is based on rearrangements of the tubulin cytoskeleton; this is also true for symbiotic nodules. Nevertheless, although for indeterminate nodules (with a long-lasting meristem) the organization of microtubules during nodule development has been studied for various species, for determinate ones (with limited meristem activity) such studies are rare. Here, we investigated bacteroid morphology and dynamics of the tubulin cytoskeleton in determinate nodules of four legume species: Glycine max, Glycine soja, Phaseolus vulgaris, and Lotus japonicus. The most pronounced differentiation of bacteroids was observed in G. soja nodules. In meristematic cells in incipient nodules of all analyzed species, the organization of both cortical and endoplasmic microtubules was similar to that described for meristematic cells of indeterminate nodules. In young infected cells in developing nodules of all four species, cortical microtubules formed irregular patterns (microtubules were criss-crossed) and endoplasmic ones were associated with infection threads and infection droplets. Surprisingly, in uninfected cells the patterns of cortical microtubules differed in nodules of G. max and G. soja on the one hand, and P. vulgaris and L. japonicus on the other. The first two species exhibited irregular patterns, while the remaining two exhibited regular ones (microtubules were oriented transversely to the longitudinal axis of cell) that are typical for uninfected cells of indeterminate nodules. In contrast to indeterminate nodules, in mature determinate nodules of all four studied species, cortical microtubules formed a regular pattern in infected cells. Thus, our analysis revealed common patterns of tubulin cytoskeleton in the determinate nodules of four legume species, and species-specific differences were associated with the organization of cortical microtubules in uninfected cells. When compared with indeterminate nodules, the most pronounced differences were associated with the organization of cortical microtubules in nitrogen-fixing infected cells. The revealed differences indicated a possible transition during evolution of infected cells from anisotropic growth in determinate nodules to isodiametric growth in indeterminate nodules. It can be assumed that this transition provided an evolutionary advantage to those legume species with indeterminate nodules, enabling them to host symbiosomes in their infected cells more efficiently.

RevDate: 2022-05-13

Lo R, Dougan KE, Chen Y, et al (2022)

Alignment-Free Analysis of Whole-Genome Sequences From Symbiodiniaceae Reveals Different Phylogenetic Signals in Distinct Regions.

Frontiers in plant science, 13:815714.

Dinoflagellates of the family Symbiodiniaceae are predominantly essential symbionts of corals and other marine organisms. Recent research reveals extensive genome sequence divergence among Symbiodiniaceae taxa and high phylogenetic diversity hidden behind subtly different cell morphologies. Using an alignment-free phylogenetic approach based on sub-sequences of fixed length k (i.e. k-mers), we assessed the phylogenetic signal among whole-genome sequences from 16 Symbiodiniaceae taxa (including the genera of Symbiodinium, Breviolum, Cladocopium, Durusdinium and Fugacium) and two strains of Polarella glacialis as outgroup. Based on phylogenetic trees inferred from k-mers in distinct genomic regions (i.e. repeat-masked genome sequences, protein-coding sequences, introns and repeats) and in protein sequences, the phylogenetic signal associated with protein-coding DNA and the encoded amino acids is largely consistent with the Symbiodiniaceae phylogeny based on established markers, such as large subunit rRNA. The other genome sequences (introns and repeats) exhibit distinct phylogenetic signals, supporting the expected differential evolutionary pressure acting on these regions. Our analysis of conserved core k-mers revealed the prevalence of conserved k-mers (>95% core 23-mers among all 18 genomes) in annotated repeats and non-genic regions of the genomes. We observed 180 distinct repeat types that are significantly enriched in genomes of the symbiotic versus free-living Symbiodinium taxa, suggesting an enhanced activity of transposable elements linked to the symbiotic lifestyle. We provide evidence that representation of alignment-free phylogenies as dynamic networks enhances the ability to generate new hypotheses about genome evolution in Symbiodiniaceae. These results demonstrate the potential of alignment-free phylogenetic methods as a scalable approach for inferring comprehensive, unbiased whole-genome phylogenies of dinoflagellates and more broadly of microbial eukaryotes.

RevDate: 2022-05-13

Patel SU, Hauser P, J Ronan (2022)

Metabolomic Signatures of Ocean Acidification Stress in the Coral Acropora millepora.

FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 36 Suppl 1:.

The rapid acidification of seawater poses a significant threat to the persistence of coral reefs. However, taxa-specific, mechanistic understandings of holobiont responses to ocean acidification (OA) stress remain largely unknown. Understanding these mechanisms is crucial to uncovering predictive markers of OA stress. This could subsequently be used to assist field-based conservation efforts. We hypothesized that exposure to elevated pCO2 levels would decrease the abundance of primary metabolites such as amino acids and carbohydrates and increase the production of secondary metabolites, specifically those involved in cnidarian-symbiodinium cell signaling. In this study, we applied untargeted capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) to profile changes in the intracellular polar and semi-polar metabolite composition of the coral holobiont after exposure to elevated pCO2 concentrations. Nubbins of Acropora millepora were exposed to ambient (410 µatm) or elevated (805 µatm) pCO2 levels under controlled conditions over a period of 10 days. Measurement of treatment-induced bleaching was performed by quantification of symbiodinium cell density and chlorophyll a concentration. We hope to identify molecules in the metabolite profiles associated with the individual cellular responses of holobiont members to osmotic stress. Additionally, we hope to provide further insight into unknown roles of secondary and tertiary metabolite pools in cellular homeostasis and acclimation to thermal stress in the coral holobiont, and specifically the cnidarian-symbiodinium symbiosis. Our goal is for these findings to assist conservation efforts, specifically in the development of rapid tests for field-based conservation efforts.

RevDate: 2022-05-13

Toyoda HC, Chen S, MB Berkmen (2022)

Role of ConE's ATPase Motifs in Protein-Protein Interactions within the Conjugation Machinery of Bacillus subtilis.

FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 36 Suppl 1:.

Conjugation is the transfer of DNA from one bacterial cell to another. Conjugation is a major form of horizontal gene transfer, resulting in the spread of genes that play roles in antibiotic resistance, virulence, symbiosis and metabolism. ICEBs1 is an integrative and conjugative element of Bacillus subtilis. The conjugation machinery that transfers DNA is a Type 4 Secretion System (T4SS). The ICEBs1 T4SS includes the proteins ConB, ConC, ConD, ConE, ConG, ConQ, and CwlT. The focus of our work is the ConE peripheral membrane protein, which belongs to the VirB4 family of ATPases. We analyzed whether ConE interacts with any of the other ICEBs1 T4SS proteins using bacterial two hybrid (BACTH). We found that ConE interacts with itself, ConB, and ConQ. We used site-directed mutagenesis of the conE gene to make alanine substitutions within five conserved residues within ATPase motifs of the ConE protein that have previously been shown to be critical for mating. We used BACTH to determine if these mutations affect ConE's protein interactions. We discovered that interaction of ConE with itself or ConB is unaffected by mutations in any of the ATPase residues tested, but that the ConE-ConQ interaction depends on two conserved residues within the ATPase motifs. Our research sheds new light on the role of conserved residues within the ATPase motifs of ConE.

RevDate: 2022-05-13

Chakraborty S, Valdés-López O, Stonoha-Arther C, et al (2022)

Transcription Factors Controlling the Rhizobium-Legume Symbiosis: Integrating Infection, Organogenesis, and the Abiotic Environment.

Plant & cell physiology pii:6584650 [Epub ahead of print].

Legume roots engage in a symbiotic relationship with rhizobia leading to the development of nitrogen-fixing nodules. Nodule development is a sophisticated process and is under the tight regulation of the plant. The symbiosis initiates with a signal exchange between the two partners, followed by the development of a new organ colonized by rhizobia. Over two decades of study have shed light on the transcriptional regulation of rhizobium-legume symbiosis. A large number of transcription factors (TFs) have been implicated in one or more stages of this symbiosis. Legumes must monitor nodule development amidst a dynamic physical environment. Some environmental factors are conducive to nodulation, whereas others are stressful. The modulation of rhizobium-legume symbiosis by the abiotic environment adds another layer of complexity and is also transcriptionally regulated. Several symbiotic TFs act as integrators between symbiosis and the response to the abiotic environment. In this review, we trace the role of various TFs involved in rhizobium-legume symbiosis along its developmental route and highlight the ones that also act as communicators between this symbiosis and the response to the abiotic environment. Finally, we discuss contemporary approaches to study TF-target interactions in plants and probe their potential utility in the field of rhizobium-legume symbiosis.

RevDate: 2022-05-13

Ji X, Xia Y, Zhang H, et al (2022)

The microscopic mechanism between endophytic fungi and host plants: From recognition to building stable mutually beneficial relationships.

Microbiological research, 261:127056 pii:S0944-5013(22)00096-9 [Epub ahead of print].

Growing research suggests that endophytic fungi deeply affect plant physiology, development, and metabolism, which has become an indispensable subject in plant research. However, the micromolecular mechanisms remain vague due to the complexity of the interactions. This article summarizes the latest progress in the mechanism studies of the symbiotic relationships between endophytic fungi and plants. We address the aspects from signal generation, plant defense, to fungal coping strategies to establish the balanced constraint relationships between fungi and their hosts that finally form "a community of shared future." These processes do not occur in isolation but in synergy. Both endophytic fungi and their host plants contribute to establishing the stable symbiosis. New insights have been provided into a deeper understanding of the occurrence of species interactions and their applications to solving practical problems.

RevDate: 2022-05-13

Teli P, Kale V, A Vaidya (2022)

Mesenchymal stromal cells-derived secretome protects Neuro-2a cells from oxidative stress-induced loss of neurogenesis.

Experimental neurology pii:S0014-4886(22)00132-7 [Epub ahead of print].

Neurodegenerative diseases (ND) are characterized by debilitating medical conditions that principally affect the neuronal cells in the human brain. One of the major reasons that there are no effective drugs for the treatment of ND is because researchers face technical challenges while conducting studies to understand the molecular mechanism behind ND. Although various studies have established in vitro neurodegenerative model systems, we feel that these model systems are not physiologically relevant, as they do not mimic the in vivo situation of chronic insult. Therefore, the primary aim of this study was to establish an in vitro neurodegenerative model system by inducing oxidative stress in such a way that the neuronal cells remain viable, but lose their structural and functional characteristics. Using a murine neuroblastoma cell line, Neuro-2a, we demonstrate that induction of oxidative stress significantly affects various neurite outgrowth parameters and reduces the expression of neuronal and autophagy markers without causing apoptosis in them. Previously, we have discussed the possible therapeutic applications of mesenchymal stromal cells (MSCs) and their secretome in the treatment of ND. Here, using two distinct approaches, we show that when Neuro-2a cells subjected to oxidative stress are exposed to MSC-derived conditioned medium (secretome), they exhibit a significant improvement in various neuronal parameters and in the expression of neuronal markers. Overall, our findings support the salutary role of MSC-derived secretome in rescuing the oxidative stress-induced loss of neurogenesis using a physiologically relevant in vitro model system. Our data underscore the propensity of the MSC-secretome in reversing ND.

RevDate: 2022-05-13

Cui G, Liew YJ, Konciute MK, et al (2022)

Nutritional control regulates symbiont proliferation and life history in coral-dinoflagellate symbiosis.

BMC biology, 20(1):103.

BACKGROUND: The coral-Symbiodiniaceae symbiosis is fundamental for the coral reef ecosystem. Corals provide various inorganic nutrients to their algal symbionts in exchange for the photosynthates to meet their metabolic demands. When becoming symbionts, Symbiodiniaceae cells show a reduced proliferation rate and a different life history. While it is generally believed that the animal hosts play critical roles in regulating these processes, far less is known about the molecular underpinnings that allow the corals to induce the changes in their symbionts.

RESULTS: We tested symbiont cell proliferation and life stage changes in vitro in response to different nutrient-limiting conditions to determine the key nutrients and to compare the respective symbiont transcriptomic profiles to cells in hospite. We then examined the effects of nutrient repletion on symbiont proliferation in coral hosts and quantified life stage transitions in vitro using time-lapse confocal imaging. Here, we show that symbionts in hospite share gene expression and pathway activation profiles with free-living cells under nitrogen-limited conditions, strongly suggesting that symbiont proliferation in symbiosis is limited by nitrogen availability.

CONCLUSIONS: We demonstrate that nitrogen limitation not only suppresses cell proliferation but also life stage transition to maintain symbionts in the immobile coccoid stage. Nutrient repletion experiments in corals further confirmed that nitrogen availability is the major factor limiting symbiont density in hospite. Our study emphasizes the importance of nitrogen in coral-algae interactions and, more importantly, sheds light on the crucial role of nitrogen in symbiont life history regulation.

RevDate: 2022-05-13

Bastías DA, Gundel PE, Johnson RD, et al (2022)

How and when fungal endophytes can eliminate the plant growth-defence trade-off: mechanistic perspectives: A response to Atala et al. (2022) 'Fungal endophytes improve the performance of host plants but do not eliminate the growth/defence trade-off'.

RevDate: 2022-05-13

Saura JR, Dwivedi YK, D Palacios-Marqués (2022)

Editorial: Online User Behavior and User-Generated Content.

Frontiers in psychology, 13:895467.

RevDate: 2022-05-13

Thakur H, Pareek P, Sayyad MG, et al (2022)

Association of Premenstrual Syndrome with Adiposity and Nutrient Intake Among Young Indian Women.

International journal of women's health, 14:665-675 pii:359458.

Abstract: Premenstrual syndrome (PMS) refers to a heterogenous group of symptoms occurring in luteal phase of the menstrual cycle. Women of childbearing age are affected by PMS, and it may impact their quality of life. Various factors related to the biology of menstruation, hormones, and lifestyle are associated with PMS.

Purpose: To explore the incidence and severity of PMS among students in India and its correlation with nutrient intake, adiposity, and lifestyle factors.

Methods: A semi-structured questionnaire was used to collect data on menstrual pattern, nutrient intake, dietary habits, and physical activity. Moose's Menstrual Distress Questionnaire and Premenstrual Symptoms Screening Tool were employed for the identification and classification of PMS. Anthropometric indices included height, weight, body mass index, waist circumference, hip circumference, waist-to-hip ratio, and four-site skinfold thickness-tricep, bicep, subscapular, and suprailiac.

Results: Of the 330 participants, 71.3% reported to have experienced at least one symptom of PMS. Furthermore, 46.9% had mild PMS, 31.5% had moderate PMS, 8.3% had strong PMS, and 13.3% had no symptoms. Anxiety and irritability were the most observed symptoms. The mean body mass index (BMI) of the participants was within the normal range (21.76 ± 4.81 kg/m2); however, body fat percentage was above the normal range (33.95% ± 4.89%). PMS severity was significantly correlated with body fat percentage and BMI. Nutrient intake was significantly lower than the recommended dietary allowance (RDA), but dietary fat consumption was higher than the RDA. Protein intake was higher in participants with mild PMS than those with moderate and severe PMS (p<0.05). An inverse association between oilseed consumption and PMS was observed.

Conclusion: PMS was associated with anthropometric parameters, nutrient intake, and dietary preference. PMS showed correlation with the intake of calorie-rich foods, sweets, and fried salted snacks, whereas consumption of oilseeds alleviated its incidence.

RevDate: 2022-05-13

Chen W, Ma J, Jiang Y, et al (2022)

Selective Maternal Seeding and Rearing Environment From Birth to Weaning Shape the Developing Piglet Gut Microbiome.

Frontiers in microbiology, 13:795101.

The acquisition and development of the mammalian microbiome early in life are critical to establish a healthy host-microbiome symbiosis. Despite recent advances in understanding microbial sources in infants, the relative contribution of various microbial sources to the colonization of the gut microbiota in pigs remains unclear. Here, we longitudinally sampled the microbiota of 20 sow-piglet pairs (three piglets per sow) reared under identical conditions from multiple body sites and the surrounding weaning environment from birth to 28 days postpartum (1,119 samples in total). Source-tracking analysis revealed that the contribution of various microbial sources to the piglet gut microbiome gradually changed over time. The neonatal microbiota was initially sparsely populated, and the predominant contribution was from the maternal vaginal microbiota that increased gradually from 69.0% at day 0 to 89.3% at day 3 and dropped to 0.28% at day 28. As the piglets aged, the major microbial community patterns were most strongly associated with the sow feces and slatted floor, with contributions increasing from 0.52 and 9.6% at day 0 to 62.1 and 33.8% at day 28, respectively. The intestinal microbial diversity, composition, and function significantly changed as the piglets aged, and 30 age-discriminatory bacterial taxa were identified with distinctive time-dependent shifts in their relative abundance, which likely reflected the effect of the maternal and environmental microbial sources on the selection and adaptation of the piglet gut microbiota. Overall, these data demonstrate that the vaginal microbiota is the primary source of the gut microbiota in piglets within 3 days after birth and are gradually replaced by the sow fecal and slatted floor microbiota over time. These findings may offer novel strategies to promote the establishment of exogenous symbiotic microbes to improve piglet gut health.

RevDate: 2022-05-13

Atala C, Acuña-Rodríguez IS, Torres-Díaz C, et al (2022)

Fungal endophytes improve the performance of host plants but do not eliminate the growth/defence trade-off.

RevDate: 2022-05-13

Moriyama M, Hayashi T, T Fukatsu (2022)

A mucin protein predominantly expressed in the female-specific symbiotic organ of the stinkbug Plautia stali.

Scientific reports, 12(1):7782.

Diverse insects are obligatorily associated with microbial symbionts, wherein the host often develops special symbiotic organs and vertically transmits the symbiont to the next generation. What molecular factors underpin the host-symbiont relationship is of great interest but poorly understood. Here we report a novel protein preferentially produced in a female-specific symbiotic organ of the stinkbug Plautia stali, whose posterior midgut develops numerous crypts to host a Pantoea-allied bacterial mutualist. In adult females, several posteriormost crypts are conspicuously enlarged, presumably specialized for vertical symbiont transmission. We detected conspicuous protein bands specific to the female's swollen crypts by gel electrophoresis, and identified them as representing a novel mucin-like glycoprotein. Histological inspections confirmed that the mucin protein is localized to the female's swollen crypts, coexisting with a substantial population of the symbiotic bacteria, and excreted from the swollen crypts to the midgut main tract together with the symbiotic bacteria. Using RNA interference, we successfully suppressed production of the mucin protein in adult females of P. stali. However, although the mucin protein was depleted, the symbiont population persisted in the swollen crypts, and vertical symbiont transmission to the next generation occurred. Possible biological roles and evolutionary trajectory of the symbiosis-related mucin protein are discussed.

RevDate: 2022-05-11

Merlin BL, Moraes GJ, FL Cônsoli (2022)

The Microbiota of a Mite Prey-Predator System on Different Host Plants Are Characterized by Dysbiosis and Potential Functional Redundancy.

Microbial ecology [Epub ahead of print].

Microbiota has diverse roles in the life cycles of their hosts, affecting their growth, development, behavior, and reproduction. Changes in physiological conditions of the host can also impact the assemblage of host-associated microorganisms. However, little is known of the effects of host plant-prey-predatory mite interactions on mite microbiota. We compared the microbial communities of eggs and adult females of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and of adult females of the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) on four different host plants (cotton, maize, pinto bean, and tomato) by metabarcoding sequencing of the V3-V4 region of the 16S ribosomal RNA gene (16S rRNA), using the Illumina MiSeq platform. Only the egg microbiota of T. urticae was affected by the host plant. The microbiota of the predatory mite N. californicus was very different from that of its prey, and the predator microbiota was unaffected by the different host plant-prey systems tested. Only the microbiota of the eggs of T. urticae carried Serratia as a high fidelity-biomarker, but their low abundance in T. urticae adult females suggests that the association between Serratia and T. urticae is accidental. Biomarker bacteria were also detected in the microbiota of adult females of T. urticae and N. californicus, with different biomarkers in each host plant species. The microbiota associated with eggs and adult females of T. urticae and adult females of N. californicus differed in their functional potential contributions to the host mite.

RevDate: 2022-05-11

Khan A, Wadood SF, Chen M, et al (2022)

Effector-triggered inhibition of nodulation: a rhizobial effector protease targets soybean kinase GmPBS1-1.

Plant physiology pii:6584019 [Epub ahead of print].

Type III protein secretion systems of nitrogen-fixing rhizobia deliver effector proteins into leguminous host cells to promote or inhibit the nodule symbiosis. However, mechanisms underlying effector-triggered inhibition of nodulation remain largely unknown. Nodulation outer protein T (NopT) of Sinorhizobium sp. NGR234 is an effector protease related to the Pseudomonas effector AvrPphB (Avirulence protein Pseudomonas phaseolicola B). Here, we constructed NGR234 mutants producing different NopT variants and found that protease activity of NopT negatively affects nodulation of smooth crotalaria (Crotalaria pallida). NopT variants lacking residues required for autocleavage and subsequent lipidation showed reduced symbiotic effects and were not targeted to the plasma membrane. We further noticed that Sinorhizobium fredii strains possess a mutated nopT gene. S. fredii USDA257 expressing nopT of NGR234 induced considerably fewer nodules in soybean (Glycine max) cv. Nenfeng 15 but not in other cultivars. Effector perception was further examined in NopT-expressing leaves of Arabidopsis (Arabidopsis thaliana) and found to be dependent on the target protein AtPBS1 (Arabidopsis AvrPphB susceptible 1) and the associated resistance protein AtRPS5 (Arabidopsis Resistance to Pseudomonas Syringae 5). Experiments with Nicotiana benthamiana plants indicated that the soybean homolog GmPBS1-1 associated with AtRPS5 can perceive NopT. Further analysis showed that NopT cleaves AtPBS1 and GmPBS1-1 and thus can activate these target proteins. Insertion of a DKM motif at the cleavage site of GmPBS1-1 resulted in increased proteolysis. Nodulation tests with soybeans expressing an autoactive GmPBS1-1 variant indicated that activation of a GmPBS1-1-mediated resistance pathway impairs nodule formation in cv. Nenfeng 15. Our findings suggest that legumes face an evolutionary dilemma of either developing effector-triggered immunity against pathogenic bacteria or establishing symbiosis with suboptimally adapted rhizobia producing pathogen-like effectors.

RevDate: 2022-05-11

Mucci NC, Jones KA, Cao M, et al (2022)

Apex Predator Nematodes and Meso-Predator Bacteria Consume Their Basal Insect Prey through Discrete Stages of Chemical Transformations.

mSystems [Epub ahead of print].

Microbial symbiosis drives physiological processes of higher-order systems, including the acquisition and consumption of nutrients that support symbiotic partner reproduction. Metabolic analytics provide new avenues to examine how chemical ecology, or the conversion of existing biomass to new forms, changes over a symbiotic life cycle. We applied these approaches to the nematode Steinernema carpocapsae, its mutualist bacterium, Xenorhabdus nematophila, and the insects they infect. The nematode-bacterium pair infects, kills, and reproduces in an insect until nutrients are depleted. To understand the conversion of insect biomass over time into either nematode or bacterium biomass, we integrated information from trophic, metabolomic, and gene regulation analyses. Trophic analysis established bacteria as meso-predators and primary insect consumers. Nematodes hold a trophic position of 4.6, indicative of an apex predator, consuming bacteria and likely other nematodes. Metabolic changes associated with Galleria mellonella insect bioconversion were assessed using multivariate statistical analyses of metabolomics data sets derived from sampling over an infection time course. Statistically significant, discrete phases were detected, indicating the insect chemical environment changes reproducibly during bioconversion. A novel hierarchical clustering method was designed to probe molecular abundance fluctuation patterns over time, revealing distinct metabolite clusters that exhibit similar abundance shifts across the time course. Composite data suggest bacterial tryptophan and nematode kynurenine pathways are coordinated for reciprocal exchange of tryptophan and NAD+ and for synthesis of intermediates that can have complex effects on bacterial phenotypes and nematode behaviors. Our analysis of pathways and metabolites reveals the chemistry underlying the recycling of organic material during carnivory. IMPORTANCE The processes by which organic life is consumed and reborn in a complex ecosystem were investigated through a multiomics approach applied to the tripartite Xenorhabdus bacterium-Steinernema nematode-Galleria insect symbiosis. Trophic analyses demonstrate the primary consumers of the insect are the bacteria, and the nematode in turn consumes the bacteria. This suggests the Steinernema-Xenorhabdus mutualism is a form of agriculture in which the nematode cultivates the bacterial food sources by inoculating them into insect hosts. Metabolomics analysis revealed a shift in biological material throughout progression of the life cycle: active infection, insect death, and conversion of cadaver tissues into bacterial biomass and nematode tissue. We show that each phase of the life cycle is metabolically distinct, with significant differences including those in the tricarboxylic acid cycle and amino acid pathways. Our findings demonstrate that symbiotic life cycles can be defined by reproducible stage-specific chemical signatures, enhancing our broad understanding of metabolic processes that underpin a three-way symbiosis.

RevDate: 2022-05-11

Pfab F, Brown AL, Detmer AR, et al (2022)

Timescale separation and models of symbiosis: state space reduction, multiple attractors and initialization.

Conservation physiology, 10(1):coac026 pii:coac026.

Dynamic Energy Budget models relate whole organism processes such as growth, reproduction and mortality to suborganismal metabolic processes. Much of their potential derives from extensions of the formalism to describe the exchange of metabolic products between organisms or organs within a single organism, for example the mutualism between corals and their symbionts. Without model simplification, such models are at risk of becoming parameter-rich and hence impractical. One natural simplification is to assume that some metabolic processes act on 'fast' timescales relative to others. A common strategy for formulating such models is to assume that 'fast' processes equilibrate immediately, while 'slow' processes are described by ordinary differential equations. This strategy can bring a subtlety with it. What if there are multiple, interdependent fast processes that have multiple equilibria, so that additional information is needed to unambiguously specify the model dynamics? This situation can easily arise in contexts where an organism or community can persist in a 'healthy' or an 'unhealthy' state with abrupt transitions between states possible. To approach this issue, we offer the following: (a) a method to unambiguously complete implicitly defined models by adding hypothetical 'fast' state variables; (b) an approach for minimizing the number of additional state variables in such models, which can simplify the numerical analysis and give insights into the model dynamics; and (c) some implications of the new approach that are of practical importance for model dynamics, e.g. on the bistability of flux dynamics and the effect of different initialization choices on model outcomes. To demonstrate those principles, we use a simplified model for root-shoot dynamics of plants and a related model for the interactions between corals and endosymbiotic algae that describes coral bleaching and recovery.

RevDate: 2022-05-11
CmpDate: 2022-05-11

Zakeri Z, Junne S, Jäger F, et al (2022)

Lichen cell factories: methods for the isolation of photobiont and mycobiont partners for defined pure and co-cultivation.

Microbial cell factories, 21(1):80.

BACKGROUND: Due to their huge biodiversity and the capability to produce a wide range of secondary metabolites, lichens have a great potential in biotechnological applications. They have, however, hardly been used as cell factories to date, as it is considered to be difficult and laborious to cultivate lichen partners in pure or co-culture in the laboratory. The various methods used to isolate lichen fungi, based on either the ascospores, the conidia, or the thallus, have so far not been compared or critically examined. Therefore, here we systematically investigate and compare the known methods and two new methods to identify the most suitable technology for isolation of fungi from lichens.

RESULTS: Within this study six lichen fungi species were isolated and propagated as pure cultures. All of them formed colonies within one month. In case of lichens with ascocarps the spore discharge was the most suitable method. Spores were already discharged within 2 days and germinated within only four days and the contamination rate was low. Otherwise, the soredia and thallus method without homogenization, as described in this work, are also well suited to obtain pure fungal cultures. For the isolation of algae, we were also successful with the thallus method without homogenization.

CONCLUSION: With the methods described here and the proposed strategic approach, we believe that a large proportion of the lichen fungi can be cultivated within a reasonable time and effort. Based on this, methods of controlled cultivation and co-cultivation must now be developed in order to use the potential of lichens with regard to their secondary metabolites, but also for other applications.

RevDate: 2022-05-11
CmpDate: 2022-05-11

de Raad J, Päckert M, Irestedt M, et al (2022)

Speciation and population divergence in a mutualistic seed dispersing bird.

Communications biology, 5(1):429.

Bird-mediated seed dispersal is crucial for the regeneration and viability of ecosystems, often resulting in complex mutualistic species networks. Yet, how this mutualism drives the evolution of seed dispersing birds is still poorly understood. In the present study we combine whole genome re-sequencing analyses and morphometric data to assess the evolutionary processes that shaped the diversification of the Eurasian nutcracker (Nucifraga), a seed disperser known for its mutualism with pines (Pinus). Our results show that the divergence and phylogeographic patterns of nutcrackers resemble those of other non-mutualistic passerine birds and suggest that their early diversification was shaped by similar biogeographic and climatic processes. The limited variation in foraging traits indicates that local adaptation to pines likely played a minor role. Our study shows that close mutualistic relationships between bird and plant species might not necessarily act as a primary driver of evolution and diversification in resource-specialized birds.

RevDate: 2022-05-11
CmpDate: 2022-05-11

Koltz AM, Civitello DJ, Becker DJ, et al (2022)

Sublethal effects of parasitism on ruminants can have cascading consequences for ecosystems.

Proceedings of the National Academy of Sciences of the United States of America, 119(20):e2117381119.

SignificanceWe found that pervasive parasitic infections reduce herbivory rates and can trigger trophic cascades. Lethal parasites clearly have cascading impacts on ecosystems, but whether common sublethal infections have similar effects is largely unknown. Using a mathematical model, we probed how parasites that reduce host survival, fecundity, or feeding rates can indirectly alter producer biomass in a helminth-ruminant system. We found that both lethal and sublethal infections triggered trophic cascades by altering the biomass of ruminant herbivore hosts and their resources. However, a global meta-analysis revealed that helminths tend to have pervasive sublethal effects on free-living ruminants, including by reducing host feeding rates. Our findings suggest there are widespread, but overlooked, ecological consequences of sublethal infections in natural ecosystems.

RevDate: 2022-05-11
CmpDate: 2022-05-11

Zaw M, Rathjen JR, Zhou Y, et al (2022)

Rhizobial diversity is associated with inoculation history at a two-continent scale.

FEMS microbiology ecology, 98(5):.

A total of 120 Mesorhizobium strains collected from the central dry zone of Myanmar were analyzed in a pot experiment to evaluate nodulation and symbiotic effectiveness (SE%) in chickpea plants. Phylogenetic analyses revealed all strains belonged to the genus Mesorhizobium according to 16-23S rDNA IGS and the majority of chickpea nodulating rhizobia in Myanmar soils were most closely related to M. gobiense, M. muleiense, M. silamurunense, M. tamadayense and M. temperatum. Around two-thirds of the Myanmar strains (68%) were most closely related to Indian strain IC-2058 (CA-181), which is also most closely related to M. gobiense. There were no strains that were closely related to the cognate rhizobial species to nodulate chickpea: M. ciceri and M. mediterraneum. Strains with diverse 16S-23S rDNA IGS shared similar nodC and nifH gene sequences with chickpea symbionts. Detailed sequence analysis of nodC and nifH found that the strains in Myanmar were somewhat divergent from the group including M. ciceri and were more closely related to M. muleiense and IC-2058. A cross-continent analysis between strains isolated in Australia compared with Myanmar found that there was little overlap in species, where Australian soils were dominated with M. ciceri, M. temperatum and M. huakuii. The only co-occurring species found in both Myanmar and Australia were M. tamadayense and M. silumurunense. Continued inoculation with CC1192 may have reduced diversity of chickpea strains in Australian soils. Isolated strains in Australian and Myanmar had similar adaptive traits, which in some cases were also phylogenetically related. The genetic discrepancy between chickpea nodulating strains in Australia and Myanmar is not only due to inoculation history but to adaptation to soil conditions and crop management over a long period, and there has been virtually no loss of symbiotic efficiency over this time in strains isolated from soils in Myanmar.

RevDate: 2022-05-11
CmpDate: 2022-05-11

Adjei JA, Aserse AA, Yli-Halla M, et al (2022)

Phylogenetically diverse Bradyrhizobium genospecies nodulate Bambara groundnut (Vigna subterranea L. Verdc) and soybean (Glycine max L. Merril) in the northern savanna zones of Ghana.

FEMS microbiology ecology, 98(5):.

A total of 102 bacterial strains isolated from nodules of three Bambara groundnut and one soybean cultivars grown in nineteen soil samples collected from northern Ghana were characterized using multilocus gene sequence analysis. Based on a concatenated sequence analysis (glnII-rpoB-recA-gyrB-atpD-dnaK), 54 representative strains were distributed in 12 distinct lineages, many of which were placed mainly in the Bradyrhizobium japonicum and Bradyrhizobium elkanii supergroups. Twenty-four of the 54 representative strains belonged to seven putative novel species, while 30 were conspecific with four recognized Bradyrhizobium species. The nodA phylogeny placed all the representative strains in the cosmopolitan nodA clade III. The strains were further separated in seven nodA subclusters with reference strains mainly of African origin. The nifH phylogeny was somewhat congruent with the nodA phylogeny, but both symbiotic genes were mostly incongruent with the core housekeeping gene phylogeny indicating that the strains acquired their symbiotic genes horizontally from distantly related Bradyrhizobium species. Using redundancy analysis, the distribution of genospecies was found to be influenced by the edaphic factors of the respective sampling sites. In general, these results mainly underscore the high genetic diversity of Bambara groundnut-nodulating bradyrhizobia in Ghanaian soils and suggest a possible vast resource of adapted inoculant strains.

RevDate: 2022-05-10

Chen KH, J Nelson (2022)

A Scoping Review of Bryophyte Microbiota: Diverse Microbial Communities in Small Plant Packages.

Journal of experimental botany pii:6583427 [Epub ahead of print].

Plant health depends not only on the condition of the plant itself but also on its diverse community of microbes, or microbiota. Just like the better-studied angiosperms, bryophytes (mosses, liverworts, and hornworts) harbor diverse communities of bacteria, archaea, fungi, and other microbial eukaryotes. Bryophytes are increasingly recognized as important model systems for understanding plant evolution, development, physiology, and symbiotic interactions. Much of the work on bryophyte microbiota in the past focused on specific symbiont types for each bryophyte group, but more recent studies have started to expand the view. Therefore, this review integrates studies of bryophyte microbes from both scopes to provide a holistic view of the existing research for each bryophyte group and on key themes. The systematic search also reveals the taxonomic and geographic biases in this field, including a severe underrepresentation of the tropics, very few studies on viruses or eukaryotic microbes beyond fungi, and overrepresentation of mycorrhizal fungi studies in liverworts. Such gaps may lead to errors in conclusions about evolutionary patterns in symbiosis. This analysis points to a wealth of future research directions that promise to reveal how the distinct life cycles and physiology of bryophytes interact with their microbiota.

RevDate: 2022-05-10

Kumar H, Kumar N, N Kaur (2022)

Non-Standardized Terminology in Healthcare: Shortcomings and Subsequent Rectifications [Letter].

Infection and drug resistance, 15:2369-2370 pii:370670.

RevDate: 2022-05-09

Zhang H, Mascher M, Abbo S, et al (2022)

Advancing Grain Legumes Domestication and Evolution Studies with Genomics.

Plant & cell physiology pii:6582909 [Epub ahead of print].

Grain legumes were domesticated in parallel with cereals in several regions of the world and formed the economic basis of early farming cultures. Since then, legumes have played a vital role in human and animal diets and in fostering agrobiodiversity. Increasing grain legume cultivation will be crucial to safeguard nutritional security and the resilience of agricultural ecosystems across the globe. A better understanding of the molecular underpinnings of domestication and crop evolution of grain legumes may be translated into practical approaches in modern breeding programs to stabilize yield, which is threatened by evolving pathogens and changing climates. During recent decades, domestication research in all crops has greatly benefitted from the fast progress in genomics technologies. Yet still, many questions surrounding the domestication and diversification of legumes remain unanswered. In this review, we assess the potential of genomic approaches in grain legume research. We describe the centers of origin and the crucial domestication traits of grain legumes. In addition, we survey the effect of domestication on both above-ground and below-ground traits that have economic importance. Finally, we discuss open questions in grain legume domestication and diversification and outline how to bridge the gap between the preservation of historic crop diversity and their utilization in modern plant breeding.

RevDate: 2022-05-09

Pang L, Khan F, Dunterman M, et al (2022)

Pharmacological targeting of the tumor-immune symbiosis in glioblastoma.

Trends in pharmacological sciences pii:S0165-6147(22)00082-7 [Epub ahead of print].

Glioblastoma (GBM) is the most common and highly lethal form of primary brain tumor in adults. The median survival of GBM patients is approximately 14-16 months despite multimodal therapies. Emerging evidence has substantiated the critical role of symbiotic interactions between GBM cells and noncancerous immune cells (e.g., myeloid cells and T cells) in regulating tumor progression and therapy resistance. Approaches to target the tumor-immune symbiosis have emerged as a promising therapeutic strategy for GBM. Here, we review the recent developments for pharmacological targeting of the GBM-immune symbiosis and highlight the role of such strategies to improve the effectiveness of immunotherapies in GBM.

RevDate: 2022-05-10
CmpDate: 2022-05-10

Fujita R (2021)

[Osugoroshi virus, a male-killer virus].

Uirusu, 71(1):63-70.

In insects, sex ratio bias is sometimes introduced by feminization, parthenogenesis, cytoplasmic incompatibility, or male-killing. Some intracellular bacteria such as Wolbachia or Spiroplasma has been known as male-killing agents. Here I introduce an example of non-bacterial male-killing agent, Osugoroshi virus found in oriental tea tortrix.

RevDate: 2022-05-10
CmpDate: 2022-05-10

Anonymous (2022)

David J. Lynn.

Cell reports. Medicine, 3(4):100611.

In this Q&A we speak with David Lynn, an EMBL Australia Group Leader at the South Australian Health and Medical Research Institute and a professor at Flinders University, about his research applying systems immunology approaches to better understand how pathogen and commensal microbes regulate our immune system in different contexts.

RevDate: 2022-05-10
CmpDate: 2022-05-10

Foster-Nyarko E, MJ Pallen (2022)

The microbial ecology of Escherichia coli in the vertebrate gut.

FEMS microbiology reviews, 46(3):.

Escherichia coli has a rich history as biology's 'rock star', driving advances across many fields. In the wild, E. coli resides innocuously in the gut of humans and animals but is also a versatile pathogen commonly associated with intestinal and extraintestinal infections and antimicrobial resistance-including large foodborne outbreaks such as the one that swept across Europe in 2011, killing 54 individuals and causing approximately 4000 infections and 900 cases of haemolytic uraemic syndrome. Given that most E. coli are harmless gut colonizers, an important ecological question plaguing microbiologists is what makes E. coli an occasionally devastating pathogen? To address this question requires an enhanced understanding of the ecology of the organism as a commensal. Here, we review how our knowledge of the ecology and within-host diversity of this organism in the vertebrate gut has progressed in the 137 years since E. coli was first described. We also review current approaches to the study of within-host bacterial diversity. In closing, we discuss some of the outstanding questions yet to be addressed and prospects for future research.

RevDate: 2022-05-10
CmpDate: 2022-05-10

Alonso AC, Stein M, Matías Hisgen C, et al (2022)

Abiotic factors affecting the prevalence of Wolbachia (Rickettsiaceae) in immature Aedes albopictus (Skuse) (Culicidae).

Journal of invertebrate pathology, 189:107730.

Wolbachia is a genus of gram-negative endosymbiotic bacterium of maternal transmission, located mainly in the gonads of arthropods, including mosquitoes such as Aedes albopictus. The current distribution of Ae. albopictus in Argentina is restricted to the subtropical northeastern region of the country. Here, we studied the seasonal prevalence of Wolbachia detected in Ae. albopictus larvae and the relationship between the abiotic factors of the larval microhabitat and the infection status, in Eldorado city, Misiones province, subtropical region. The prevalence of Wolbachia infection found was 76.89% (n = 312). From the total samples examined, 52.80% (n = 214) showed double infection with the wAlbA/wAlbB strains, 23.84% (n = 97) infection only with wAlbB, and 0.25% (n = 1) only with wAlbA. The prevalence of double infection did not present statistically significant differences between the sites studied. For single infection, the lowest prevalence value of the wAlbB strain (13.33%) was found in the natural park, whereas the highest was found in the family dwellings and cemeteries. Tire repair shops showed an intermediate value. The wAlbA single infection was identified once. Our results also showed an association between temperature and slightly turbid waters with exposure to the sun in the larval habitats and the probability of infection by Wolbachia.

RevDate: 2022-05-09

Yuan QS, An JC, Wang H, et al (2022)

[Construction of protoplast genetic transformation system for Mycena--symbiont of Gastrodia elata].

Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica, 47(9):2304-2308.

Mycena, a symbiont of Gastrodia elata, promotes seed germination of G. elata and plays a crucial role in the sexual reproduction of G. elata. However, the lack of genetic transformation system of Mycena blocks the research on the interaction mechanism of the two. In order to establish the protoplast transformation system of Mycena, this study analyzed the protoplast enzymatic hydrolysis system, screened the resistance markers and regeneration medium, and explored the transient transformation. After hydrolysis of Mycena hyphae with complexes enzymes for 8 h and centrifugation at 4 000 r·min~(-1), high-concentration and quality protoplast was obtained. The optimum regeneration medium for Mycena was RMV, and the optimum resistance marker was 50 mg·mL~(-1) hygromycin. The pLH-HygB-HuSHXG-GFP-HdSHXG was transformed into the protoplast of Mycena which then expressed GFP. The established protoplast transformation system of Mycena laid a foundation for analyzing the functional genes of Mycena and the molecular mechanism of the symbiosis of Mycena and G. elata.

RevDate: 2022-05-09

Chang D, Gao S, Zhou G, et al (2022)

The chromosome-level genome assembly of Astragalus sinicus and comparative genomic analyses provide new resources and insights for understanding legume-rhizobial interactions.

Plant communications, 3(2):100263 pii:S2590-3462(21)00177-2.

The legume species Astragalus sinicus (Chinese milk vetch [CMV]) has been widely cultivated for centuries in southern China as one of the most important green manures/cover crops for improving rice productivity and preventing soil degeneration. In this study, we generated the first chromosome-scale reference genome of CMV by combining PacBio and Illumina sequencing with high-throughput chromatin conformation capture (Hi-C) technology. The CMV genome was 595.52 Mb in length, with a contig N50 size of 1.50 Mb. Long terminal repeats (LTRs) had been amplified and contributed to genome size expansion in CMV. CMV has undergone two whole-genome duplication (WGD) events, and the genes retained after the WGD shared by Papilionoideae species shaped the rhizobial symbiosis and the hormonal regulation of nodulation. The chalcone synthase (CHS) gene family was expanded and was expressed primarily in the roots of CMV. Intriguingly, we found that resistance genes were more highly expressed in roots than in nodules of legume species, suggesting that their expression may be increased to bolster plant immunity in roots to cope with pathogen infection in legumes. Our work sheds light on the genetic basis of nodulation and symbiosis in CMV and provides a benchmark for accelerating genetic research and molecular breeding in the future.

RevDate: 2022-05-09
CmpDate: 2022-05-09

Lin CA, TC Bates (2022)

Free to choose: Mutualist motives for partner choice, proportional division, punishment, and help.

PloS one, 17(5):e0266735.

Mutualism-the disposition to cooperate in ways that benefit both actor and recipient-has been proposed as a key construct in the evolution of cooperation, with distinct adaptations for 1) partner choice, 2) division, 3) punishment, and 4) helping. However, no psychological validation of this 4-fold psychological structure exists, and no measure of the trait is available. To fill this need, in two pre-registered studies (total N = 902), we: (A) Develop and administer items assessing each of the four mutualist adaptations; (B) Show good fit to the predicted four factor model; (C) Demonstrate reliability and stability across time; (D) Evidence discriminant validity from existing constructs, including compassion and utilitarianism; (E) Establish external validity by predicting proportional choices in catch division, opposition to partner coercion, and reduced support for redistribution; and (F) Replicate each of these findings. Jointly, these results support the validity of mutualism, including a motive to maintain the freedom to choose, and provide reliable scales for use in integrating, further developing, and applying mutualism.

RevDate: 2022-05-09
CmpDate: 2022-05-09

Zhao Q, CL Maynard (2022)

Mucus, commensals, and the immune system.

Gut microbes, 14(1):2041342.

The immune system in the large intestine is separated from commensal microbes and comparatively rare enteric pathogens by a monolayer of diverse epithelial cells overlaid with a compact and adherent inner mucus layer and a looser outer mucus layer. Microorganisms, collectively referred to as the mucus-associated (MA) microbiota, physically inhabit this mucus barrier, resulting in a dynamic and incessant dialog to maintain both spatial segregation and immune tolerance. Recent major findings reveal novel features of the crosstalk between the immune system and mucus-associated bacteria in health and disease, as well as disease-related peripheral immune signatures indicative of host responses to these organisms. In this brief review, we integrate these novel observations into our overall understanding of host-microbiota mutualism at the colonic mucosal border and speculate on the significance of this emerging knowledge for our understanding of the prevention, development, and progression of chronic intestinal inflammation.

RevDate: 2022-05-09
CmpDate: 2022-05-09

Oberleitner L, Perrar A, Macorano L, et al (2022)

A bipartite chromatophore transit peptide and N-terminal protein processing in the Paulinella chromatophore.

Plant physiology, 189(1):152-164.

The amoeba Paulinella chromatophora contains photosynthetic organelles, termed chromatophores, which evolved independently from plastids in plants and algae. At least one-third of the chromatophore proteome consists of nucleus-encoded (NE) proteins that are imported across the chromatophore double envelope membranes. Chromatophore-targeted proteins exceeding 250 amino acids (aa) carry a conserved N-terminal extension presumably involved in protein targeting, termed the chromatophore transit peptide (crTP). Short imported proteins do not carry discernable targeting signals. To explore whether the import of proteins is accompanied by their N-terminal processing, here we identified N-termini of 208 chromatophore-localized proteins by a mass spectrometry-based approach. Our study revealed extensive N-terminal acetylation and proteolytic processing in both NE and chromatophore-encoded (CE) fractions of the chromatophore proteome. Mature N-termini of 37 crTP-carrying proteins were identified, of which 30 were cleaved in a common processing region. Surprisingly, only the N-terminal ∼50 aa (part 1) become cleaved upon import. This part contains a conserved adaptor protein-1 complex-binding motif known to mediate protein sorting at the trans-Golgi network followed by a predicted transmembrane helix, implying that part 1 anchors the protein co-translationally in the endoplasmic reticulum and mediates trafficking to the chromatophore via the Golgi. The C-terminal part 2 contains conserved secondary structural elements, remains attached to the mature proteins, and might mediate translocation across the chromatophore inner membrane. Short imported proteins remain largely unprocessed. Finally, this work illuminates N-terminal processing of proteins encoded in an evolutionary-early-stage organelle and suggests host-derived posttranslationally acting factors involved in regulation of the CE chromatophore proteome.

RevDate: 2022-05-07

Camus MF, Alexander-Lawrie B, Sharbrough J, et al (2022)

Inheritance through the cytoplasm.

Heredity [Epub ahead of print].

Most heritable information in eukaryotic cells is encoded in the nuclear genome, with inheritance patterns following classic Mendelian segregation. Genomes residing in the cytoplasm, however, prove to be a peculiar exception to this rule. Cytoplasmic genetic elements are generally maternally inherited, although there are several exceptions where these are paternally, biparentally or doubly-uniparentally inherited. In this review, we examine the diversity and peculiarities of cytoplasmically inherited genomes, and the broad evolutionary consequences that non-Mendelian inheritance brings. We first explore the origins of vertical transmission and uniparental inheritance, before detailing the vast diversity of cytoplasmic inheritance systems across Eukaryota. We then describe the evolution of genomic organisation across lineages, how this process has been shaped by interactions with the nuclear genome and population genetics dynamics. Finally, we discuss how both nuclear and cytoplasmic genomes have evolved to co-inhabit the same host cell via one of the longest symbiotic processes, and all the opportunities for intergenomic conflict that arise due to divergence in inheritance patterns. In sum, we cannot understand the evolution of eukaryotes without understanding hereditary symbiosis.

RevDate: 2022-05-07

Carrier TJ, Maldonado M, Schmittmann L, et al (2022)

Symbiont transmission in marine sponges: reproduction, development, and metamorphosis.

BMC biology, 20(1):100.

Marine sponges (phylum Porifera) form symbioses with diverse microbial communities that can be transmitted between generations through their developmental stages. Here, we integrate embryology and microbiology to review how symbiotic microorganisms are transmitted in this early-diverging lineage. We describe that vertical transmission is widespread but not universal, that microbes are vertically transmitted during a select developmental window, and that properties of the developmental microbiome depends on whether a species is a high or low microbial abundance sponge. Reproduction, development, and symbiosis are thus deeply rooted, but why these partnerships form remains the central and elusive tenet of these developmental symbioses.

RevDate: 2022-05-06

Moustafa MAM, Mohamed WMA, Lau ACC, et al (2022)

Novel symbionts and potential human pathogens excavated from argasid tick microbiomes that are shaped by dual or single symbiosis.

Computational and structural biotechnology journal, 20:1979-1992 pii:S2001-0370(22)00137-4.

Research on vector-associated microbiomes has been expanding due to increasing emergence of vector-borne pathogens and awareness of the importance of symbionts in the vector physiology. However, little is known about microbiomes of argasid (or soft-bodied) ticks due to limited access to specimens. We collected four argasid species (Argas japonicus, Carios vespertilionis, Ornithodoros capensis, and Ornithodoros sawaii) from the nests or burrows of their vertebrate hosts. One laboratory-reared argasid species (Ornithodoros moubata) was also included. Attempts were then made to isolate and characterize potential symbionts/pathogens using arthropod cell lines. Microbial community structure was distinct for each tick species. Coxiella was detected as the predominant symbiont in four tick species where dual symbiosis between Coxiella and Rickettsia or Coxiella and Francisella was observed in C. vespertilionis and O. moubata, respectively. Of note, A. japonicus lacked Coxiella and instead had Occidentia massiliensis and Thiotrichales as alternative symbionts. Our study found strong correlation between tick species and life stage. We successfully isolated Oc. massiliensis and characterized potential pathogens of genera Ehrlichia and Borrelia. The results suggest that there is no consistent trend of microbiomes in relation to tick life stage that fit all tick species and that the final interpretation should be related to the balance between environmental bacterial exposure and endosymbiont ecology. Nevertheless, our findings provide insights on the ecology of tick microbiomes and basis for future investigations on the capacity of argasid ticks to carry novel pathogens with public health importance.

RevDate: 2022-05-06

Sardelli L, Pacheco DP, Ziccarelli A, et al (2019)

Towards bioinspired in vitro models of intestinal mucus.

RSC advances, 9(28):15887-15899 pii:c9ra02368b.

Intestinal mucus is a biological structure that acts as a barrier between the external environment and the epithelium. It actively selects nutrient and drug intake, regulates the symbiosis with the intestinal microbiota and keeps the epithelium protected from the attack of pathogens. All these functions are closely connected to the chemical and structural complexity of this biological material, on which its viscoelastic and diffusive properties depend. Many models have been proposed to replicate these characteristics using glycoproteins in solution and possibly the addition of other mucus components, such as lipids and other proteins. In the field of mucus modelling, an overall view of the mucus as a material, having its own viscous, rheological and diffusive characteristics, has been undersized with respect to a pure biological-functional analysis. In this review, we propose a description of the mucus as a biomaterial, including a presentation of its chemical and structural complexity, and of its main viscoelastic-diffusive properties, in order to provide a synthesis of the characteristics necessary for the engineering of more advanced mucus models.

RevDate: 2022-05-06

Li H, Seneviratne CJ, L Jin (2022)

Human Oral Keratinocytes Challenged by Streptococcus sanguinis and Porphyromonas gingivalis Differentially Affect the Chemotactic Activity of THP-1 Monocytes.

International journal of microbiology, 2022:9112039.

Periodontal diseases are initiated by the shift from microbe-host symbiosis to dysbiosis, and the disrupted host response predominantly contributes to tissue destruction. This study investigated whether and to what extent human oral keratinocytes (HOKs) challenged by a periodontal commensal or pathogen could differentially affect the chemotactic activity of THP-1 monocytes. A selected periodontal commensal (Streptococcus sanguinis ATCC 10556) and a pathogen (Porphyromonas gingivalis ATCC 33277) were cultured and inoculated, respectively, into the lower chamber of Transwell® Permeable Supports with HOKs and incubated for 2 h or 18 h at 37°C under appropriate cell growth conditions. HOKs alone served as the control for the transwell migration assay. Well-stained THP-1 monocytes were seeded in the top chamber of the device, incubated for 2 h and then collected from the lower well for quantitation of the migrated fluorescence-labeled cells by the FACSCalibur™ flow cytometer. The statistical significance was determined using one-way ANOVA. The HOKs challenged by S. sanguinis attracted a significantly higher number of THP-1 cell migration as compared with the control after 2 h or 18 h interaction (p < 0.01). By contrast, P. gingivalis-treated HOKs exhibited a markedly reduced chemotactic effect on THP-1 cells (p < 0.01, 2 h; p < 0.05, 18 h). There was no significant difference in THP-1 cell migration among the groups with either S. sanguinis or P. gingivalis alone. The current findings on P. gingivalis-HOKs interactions with resultant paralysis of THP-1 cell chemotaxis provide further evidence that the keystone periodontopathogen P. gingivalis can evade innate defense and contribute to periodontal pathogenesis.

RevDate: 2022-05-06

Bao H, Zhang X, Su H, et al (2019)

Study on the hydrogen production ability of high-efficiency bacteria and synergistic fermentation of maize straw by a combination of strains.

RSC advances, 9(16):9030-9040 pii:c9ra00165d.

Based on the principle of reciprocal symbiosis and co-metabolism of mixed culture microorganisms, a group of high-efficiency maize straw-degrading hydrogen-producing complex bacteria X9 + B2 was developed by a strain matching optimization experiment. Systematic research and optimization experiments were carried out on the mechanism of the main controlling factors affecting the hydrogen production of the complex bacteria. The results showed that the optimum conditions for the acid blasting pre-treatment of maize straw as a substrate were as follows: when the inoculation amount was 6% and the inoculum ratio was 1 : 1, at which point, we needed to simultaneously inoculate, the initial pH was 6, the substrate concentration was 12 g L-1, and the culture time was 40 h. The complex bacteria adopted the variable temperature and speed regulation hydrogen production operational mode; after the initial temperature of 37 °C for 8 hours, the temperature was gradually increased to 40 °C for 3 hours. The initial shaker speed was 90 rpm for 20 hours, and the speed was gradually increased to 130 rpm. The maximum hydrogen production rate obtained by the complex bacteria under these conditions was 12.6 mmol g-1, which was 1.6 times that of the single strain X9 with a maximum hydrogen production rate of 5.7 mmol g-1. Through continuous subculturing and the 10th, 20th, 40th, 60th, 80th, 100th and 120th generation fermentation hydrogen production stability test analysis, no significant difference was observed between generations; the maximum difference was not more than 5%, indicating better functional properties and stability.

RevDate: 2022-05-06

Yu M, Wang Q, Tao W, et al (2020)

Interactions between arbuscular mycorrhizal fungi and soil properties jointly influence plant C, N, and P stoichiometry in West Lake, Hangzhou.

RSC advances, 10(65):39943-39953 pii:d0ra08185j.

Arbuscular mycorrhizal fungi (AMF) play important roles in terrestrial plants via mutualistic symbiosis. However, knowledge about the functions of AMF in aquatic plants remains limited. Here, four dominate emergent plant communities in West Lake, Hangzhou were chosen, the characteristics of AMF, plant C, N, and P stoichiometry, and soil properties were investigated. The results showed that both AMF infection rates and the number of AMF spore species increased, suggesting a great mutualism between AMF and emergent plants. Contents of C, N, and P in aboveground biomass and roots and their ratios varied greatly among these four emergent plants. Moreover, AMF infection frequency showed a significant negative correlation with aboveground biomass N (p < 0.05), whereas the rates of arbuscular mycorrhiza formation and vesicular formation after root infection showed significant negative correlations with root N and root N/P. Soil total C, soil total N, soil total P, and oxidation-reduction potential (ORP) were significantly associated with AMF infection characteristics. Our main findings are that the results of redundancy analysis and path analysis further indicated that soil C, N, and P contents, and ORP affected plant C, N, and P contents and their stoichiometry directly. Meanwhile, soil properties can also regulate plant ecological stoichiometry indirectly via altering AMF mycorrhiza. Our findings highlight that interactions between AMF and soil play crucial roles in regulating plant ecological stoichiometry and can be treated as a whole in investigating the relationships between plant and soil.

RevDate: 2022-05-06

Sheehy L, Cutler J, Weedall GD, et al (2022)

Microbiome Analysis of Malacopathogenic Nematodes Suggests No Evidence of a Single Bacterial Symbiont Responsible for Gastropod Mortality.

Frontiers in immunology, 13:878783.

Nematodes and bacteria are prevalent in soil ecosystems, and some have evolved symbiotic relationships. In some cases, symbionts carry out highly specialized functions: a prime example being entomopathogenic nematodes (EPNs), which vector bacteria (Xenorhabdus or Photorhabdus) into insect hosts, killing them to provide a food source for the nematodes. It is thought that the commercially available malacopathogenic (kills slugs and snails) biocontrol nematode Phasmarhabditis hermaphrodita vectors a bacterium (Moraxella osloensis) into slugs to kill them. To investigate this further we used a metagenomic approach to profile the bacteria present in the commercial strain of P. hermaphrodita, a wild strain of P. hermaphrodita and two other Phasmarhabditis species (P. californica and P. neopapillosa), after they had killed their slug host (Deroceras invadens). We show that these nematodes do not exclusively associate with one bacterium but a range of species, with members of the phyla Pseudomonadota, Bacillota, Actinobacteriota and Bacteroidota the most prevalent. The commercial strain of P. hermaphrodita had the least diverse bacterial community. Furthermore, we found that the bacterium P. hermaphrodita has been cultured on for 25 years is not the expected species M. osloensis but is Psychrobacter spp. and the only strain of the Phasmarhabditis species to associate with Psychrobacter spp. was the commercial strain of P. hermaphrodita. In summary, we found no evidence to show that P. hermaphrodita rely exclusively on one bacterium to cause host mortality but found variable and diverse bacterial communities associated with these nematodes in their slug hosts.

RevDate: 2022-05-05

Ferreira EGC, Gomes DF, Delai CV, et al (2022)

Revealing potential functions of hypothetical proteins induced by genistein in the symbiosis island of Bradyrhizobium japonicum commercial strain SEMIA 5079 (= CPAC 15).

BMC microbiology, 22(1):122.

BACKGROUND: Bradyrhizobium japonicum strain SEMIA 5079 (= CPAC 15) is a nitrogen-fixing symbiont of soybean broadly used in commercial inoculants in Brazil. Its genome has about 50% of hypothetical (HP) protein-coding genes, many in the symbiosis island, raising questions about their putative role on the biological nitrogen fixation (BNF) process. This study aimed to infer functional roles to 15 HP genes localized in the symbiosis island of SEMIA 5079, and to analyze their expression in the presence of a nod-gene inducer.

RESULTS: A workflow of bioinformatics tools/databases was established and allowed the functional annotation of the HP genes. Most were enzymes, including transferases in the biosynthetic pathways of cobalamin, amino acids and secondary metabolites that may help in saprophytic ability and stress tolerance, and hydrolases, that may be important for competitiveness, plant infection, and stress tolerance. Putative roles for other enzymes and transporters identified are discussed. Some HP proteins were specific to the genus Bradyrhizobium, others to specific host legumes, and the analysis of orthologues helped to predict roles in BNF.

CONCLUSIONS: All 15 HP genes were induced by genistein and high induction was confirmed in five of them, suggesting major roles in the BNF process.

RevDate: 2022-05-06
CmpDate: 2022-05-06

Burgos T, Fedriani JM, Escribano-Ávila G, et al (2022)

Predation risk can modify the foraging behaviour of frugivorous carnivores: Implications of rewilding apex predators for plant-animal mutualisms.

The Journal of animal ecology, 91(5):1024-1035.

Apex predators play key roles in food webs and their recovery can trigger trophic cascades in some ecosystems. Intra-guild competition can reduce the abundances of smaller predators and perceived predation risk can alter their foraging behaviour thereby limiting seed dispersal by frugivorous carnivores. However, little is known about how plant-frugivore mutualisms could be disturbed in the presence of larger predators. We evaluated the top-down effect of the regional superpredator, the Iberian lynx Lynx pardinus, on the number of visits and fruits consumed by medium-sized frugivorous carnivores, as well as the foraging behaviour of identified individuals, by examining the consumption likelihood and the foraging time. We carried out a field experiment in which we placed Iberian pear Pyrus bourgaeana fruits beneath fruiting trees and monitored pear removal by frugivorous carnivores, both inside and outside lynx ranges. Using camera traps, we recorded the presence of the red fox Vulpes vulpes, the Eurasian badger Meles meles and the stone marten Martes foina, as well as the number of fruits they consumed and their time spent foraging. Red fox was the most frequent fruit consumer carnivore. We found there were fewer visits and less fruit consumed by foxes inside lynx ranges, but lynx presence did not seem to affect badgers. We did not observe any stone marten visits inside lynx territories. The foraging behaviour of red foxes was also altered inside lynx ranges whereby foxes were less efficient, consuming less fruit per unit of time and having shorter visits. Local availability of fruit resources, forest coverage and individual personality also were important variables to understand visitation and foraging in a landscape of fear. Our results show a potential trophic cascade from apex predators to primary producers. The presence of lynx can reduce frugivorous carnivore numbers and induce shifts in their feeding behaviour that may modify the seed dispersal patterns with likely consequences for the demography of many fleshy-fruited plant species. We conclude that knowledge of the ecological interactions making up trophic webs is an asset to design effective conservation strategies, particularly in rewilding programs.

RevDate: 2022-05-06
CmpDate: 2022-05-06

Arifin AR, Reiter NH, May TW, et al (2022)

New species of Tulasnella associated with Australian terrestrial orchids in the subtribes Megastylidinae and Thelymitrinae.

Mycologia, 114(2):388-412.

Tulasnella (Tulasnellaceae) is a genus of fungus that can form mycorrhizal associations with orchids (Orchidaceae). Here we used molecular phylogenetic analyses and morphological characteristics of pure cultures across four different media to support the description of five new Tulasnella species associated with commonly occurring and endangered Australian orchids. Tulasnella nerrigaensis associates with Calochilus; T. subasymmetrica and T. kiataensis with Thelymitra; and T. korungensis and T. multinucleata with Pyrorchis and Rimacola respectively. The newly described species were primarily delimited by analyses of five loci: nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), C14436 (adenosine triphosphate [ATP] synthase), C4102 (glutamate synthase), C3304 (ATP helicase), and mt large subunit 16S rDNA (mtLSU). Tulasnella subasymmetrica is introduced for some isolates previously identified as T. asymmetrica, and this latter species is characterized from multilocus sequencing of a new isolate that matches ITS sequences from the ex-type culture. Morphological differences between the new species are slight. Tulasnella multinucleata has 6-12 nuclei per hyphal compartment which is the first instance of multinucleate rather than binucleate or trinucleate hyphal compartments in Tulasnella. The formal description of these species of Tulasnella will aid in future evolutionary and ecological studies of orchid-fungal interactions.

RevDate: 2022-05-05

Roossinck MJ (2022)

The Ups and Downs of an Out-of-the-Box Scientist with a Curious Mind.

Annual review of virology [Epub ahead of print].

My early life was challenging, and not conducive to the study of science, but my first introduction to viruses was an epiphany for me. I spent the whole of my career dedicated to understanding viruses, driven largely by curiosity. This led me down many different avenues of study, and to work with many wonderful colleagues, most of whom remain friends. Some highlights of my career include the discovery of a mutualistic three-way symbiosis involving a virus, a fungus, and a plant; genetic mapping of a pathogenicity gene in tomato; uncovering a virus in 1,000-year-old corncobs; exploring virus biodiversity in wild plants; and establishing a system to use a fungal virus to understand the epidemiology of its host. Expected final online publication date for the Annual Review of Virology, Volume 9 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

RevDate: 2022-05-05

Che XR, Lai WZ, Wang SJ, et al (2022)

Multiple PHT1 family phosphate transporters are recruited for mycorrhizal symbiosis in Eucalyptus grandis and conserved PHT1;4 is a requirement for the arbuscular mycorrhizal symbiosis.

Tree physiology pii:6577266 [Epub ahead of print].

Eucalypts engage in a mutualistic endosymbiosis with arbuscular mycorrhizal (AM) fungi to acquire mineral nutrients from soils, particularly inorganic phosphate (Pi). In return, the host plant provides organic carbons to its fungal partners. However, the mechanism by which the Eucalyptus plants acquire Pi released from the AM fungi has remained elusive. In this study, we investigated the characterization of potential PHOSPHATE TRANSPORTER1 (PHT1) family Pi transporters in AM symbiosis in Eucalyptus grandis W. Hill ex Maiden. We show that multiple PHT1 family Pi transporters were recruited for AM symbiosis in E. grandis. We further report that EgPT4, an E. grandis member of the PHT1 family, is conserved across angiosperms and is exclusively expressed in AM roots with arbuscule-containing cells and localizes to the peri-arbuscular membrane. EgPT4 was able to complement a yeast mutant strain defective in all inorganic Pi transporters and mediate Pi uptake. Importantly, EgPT4 is essential for improved E. grandis growth, total phosphorous (P) concentration and arbuscule development during symbiosis. Moreover, silencing of EgPT4 led to the induction of polyphosphate accumulation relevant genes of Rhizophagus irregularis DAOM 197198. Collectively, our results unravel a pivotal role for EgPT4 in symbiotic Pi transport across the periarbuscular membrane (PAM) required for arbuscule development in E. grandis.

RevDate: 2022-05-05

Zhang L, Li N, Wang Y, et al (2022)

Sinorhizobium meliloti ohrR genes affect symbiotic performance with alfalfa (Medicago sativa).

Environmental microbiology reports [Epub ahead of print].

Sinorhizobium meliloti infects the host plant alfalfa to induce formation of nitrogen-fixation root nodules, which inevitably elicit reactive oxygen species (ROS) bursts and organic peroxide generation. The MarR family regulator OhrR regulates the expression of chloroperoxidase and organic hydrogen resistance protein, which scavenge organic peroxides in free-living S. meliloti cells. The single mutant of ohrR genes SMc01945 (ohrR1) and SMc00098 (ohrR2) lacked symbiotic phenotypes. In this work, we identified the novel ohrR gene SMa2020 (ohrR3) and determined that ohrR genes are important for rhizobial infection, nodulation and nitrogen fixation with alfalfa. By analysing the phenotypes of the single, double and triple deletion mutants of ohrR genes, we demonstrate that ohrR1 and ohrR3 slightly affect rhizobial growth, but ohrR2 and ohrR3 influence cellular resistance to the organic peroxide, tert-butyl hydroperoxide. Deletion of ohrR1 and ohrR3 negatively affected infection thread formation and nodulation, and consequently, plant growth. Correspondingly, the expression of the ROS detoxification genes katA and sodB as well as that of the nitrogenase gene nifH was downregulated in bacteroids of the double and triple deletion mutants, which may underlie the symbiotic defects of these mutants. These findings demonstrate that OhrR proteins play a role in the S. meliloti-alfalfa symbiosis.

RevDate: 2022-05-05

Campos C, Gomes L, Rei FT, et al (2022)

Olive Fruit Fly Symbiont Population: Impact of Metamorphosis.

Frontiers in microbiology, 13:868458.

The current symbiotic view of the organisms also calls for new approaches in the way we perceive and manage our pest species. The olive fruit fly, the most important olive tree pest, is dependent on an obligate bacterial symbiont to its larvae development in the immature fruit. This symbiont, Candidatus (Ca.) Erwinia dacicola, is prevalent throughout the host life stages, and we have shown significant changes in its numbers due to olive fruit fly metamorphosis. The olive fruit fly microbiota was analyzed through 16S metabarcoding, at three development stages: last instar larvae, pupae, and adult. Besides Ca. E. dacicola, the olive fruit flies harbor a diverse bacterial flora of which 13 operational taxonomic units (grouped in 9 genera/species) were now determined to persist excluding at metamorphosis (Corynebacterium sp., Delftia sp., Enhydrobacter sp., Kocuria sp., Micrococcus sp., Propionibacterium sp., Pseudomonas sp., Raoultella sp., and Staphylococcus sp.). These findings open a new window of opportunities in symbiosis-based pest management.

RevDate: 2022-05-03

Chaudhary VB, Holland EP, Charman-Anderson S, et al (2022)

What are mycorrhizal traits?.

Trends in ecology & evolution pii:S0169-5347(22)00086-6 [Epub ahead of print].

Traits are inherent properties of organisms, but how are they defined for organismal networks such as mycorrhizal symbioses? Mycorrhizal symbioses are complex and diverse belowground symbioses between plants and fungi that have proved challenging to fit into a unified and coherent trait framework. We propose an inclusive mycorrhizal trait framework that classifies traits as morphological, physiological, and phenological features that have functional implications for the symbiosis. We further classify mycorrhizal traits by location - plant, fungus, or the symbiosis - which highlights new questions in trait-based mycorrhizal ecology designed to charge and challenge the scientific community. This new framework is an opportunity for researchers to interrogate their data to identify novel insights and gaps in our understanding of mycorrhizal symbioses.

RevDate: 2022-05-04

Miyamoto H, Asano F, Ishizawa K, et al (2022)

A potential network structure of symbiotic bacteria involved in carbon and nitrogen metabolism of wood-utilizing insect larvae.

The Science of the total environment pii:S0048-9697(22)02616-X [Epub ahead of print].

Effective biological utilization of wood biomass is necessary worldwide. Since several insect larvae can use wood biomass as a nutrient source, studies on their digestive microbial structures are expected to reveal a novel rule underlying wood biomass processing. Here, structural inferences for inhabitant bacteria involved in carbon and nitrogen metabolism for beetle larvae, an insect model, were performed to explore the potential rules. Bacterial analysis of larval feces showed enrichment of the phyla Chroloflexi, Gemmatimonadetes, and Planctomycetes, and the genera Bradyrhizobium, Chonella, Corallococcus, Gemmata, Hyphomicrobium, Lutibacterium, Paenibacillus, and Rhodoplanes, bacteria potential involved in plant growth promotion, nitrogen cycle modulation, and/or environmental protection. The fecal abundances of these bacteria were not necessarily positively correlated with their abundances in the habitat, indicating that they were selectively enriched in the feces of the larvae. Association analysis predicted that common fecal bacteria might affect carbon and nitrogen metabolism. Based on these hypotheses, structural equation modeling (SEM) statistically estimated that inhabitant bacterial groups involved in carbon and nitrogen metabolism were composed of the phylum Gemmatimonadetes and the genera Bradyrhizobium, Corallococcus, and Gemmata, which were among the fecal-enriched bacteria. Nevertheless, the selected common bacteria, i.e., the phyla Acidobacteria, Armatimonadetes, and Bacteroidetes and the genera Candidatus Solibacter, Fimbriimonas, Gemmatimonas, Sphingobium, and Methanobacterium, were necessary to obtain good fit indices in the SEM. In addition, the composition of the bacterial groups differed depending upon metabolic targets, carbon and nitrogen, and their stable isotopes, δ13C and δ15N, respectively. Thus, the statistically derived causal structural models highlighted that the larval fecal-enriched bacteria and common symbiotic bacteria might selectively play a role in wood biomass carbon and nitrogen metabolism. This information could confer a new perspective that helps us use wood biomass more efficiently and might stimulate innovation in environmental industries in the future.

RevDate: 2022-05-04

Wendlandt CE, Roberts M, Nguyen KT, et al (2022)

Negotiating mutualism: A locus for exploitation by rhizobia has a broad effect size distribution and context-dependent effects on legume hosts.

Journal of evolutionary biology [Epub ahead of print].

In mutualisms, variation at genes determining partner fitness provides the raw material upon which coevolutionary selection acts, setting the dynamics and pace of coevolution. However, we know little about variation in the effects of genes that underlie symbiotic fitness in natural mutualist populations. In some species of legumes that form root nodule symbioses with nitrogen-fixing rhizobial bacteria, hosts secrete nodule-specific cysteine-rich (NCR) peptides that cause rhizobia to differentiate in the nodule environment. However, rhizobia can cleave NCR peptides through the expression of genes like the plasmid-borne Host range restriction peptidase (hrrP), whose product degrades specific NCR peptides. Although hrrP activity can confer host exploitation by depressing host fitness and enhancing symbiont fitness, the effects of hrrP on symbiosis phenotypes depend strongly on the genotypes of the interacting partners. However, the effects of hrrP have yet to be characterised in a natural population context, so its contribution to variation in wild mutualist populations is unknown. To understand the distribution of effects of hrrP in wild rhizobia, we measured mutualism phenotypes conferred by hrrP in 12 wild Ensifer medicae strains. To evaluate context dependency of hrrP effects, we compared hrrP effects across two Medicago polymorpha host genotypes and across two experimental years for five E. medicae strains. We show for the first time in a natural population context that hrrP has a wide distribution of effect sizes for many mutualism traits, ranging from strongly positive to strongly negative. Furthermore, we show that hrrP effect size varies across host genotypes and experiment years, suggesting that researchers should be cautious about extrapolating the role of genes in natural populations from controlled laboratory studies of single genetic variants.

RevDate: 2022-05-04

Wang Y, He X, F Yu (2022)

Non-host plants: Are they mycorrhizal networks players?.

Plant diversity, 44(2):127-134 pii:S2468-2659(21)00081-0.

Common mycorrhizal networks (CMNs) that connect individual plants of the same or different species together play important roles in nutrient and signal transportation, and plant community organization. However, about 10% of land plants are non-mycorrhizal species with roots that do not form any well-recognized types of mycorrhizas; and each mycorrhizal fungus can only colonize a limited number of plant species, resulting in numerous non-host plants that could not establish typical mycorrhizal symbiosis with a specific mycorrhizal fungus. If and how non-mycorrhizal or non-host plants are able to involve in CMNs remains unclear. Here we summarize studies focusing on mycorrhizal-mediated host and non-host plant interaction. Evidence has showed that some host-supported both arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) hyphae can access to non-host plant roots without forming typical mycorrhizal structures, while such non-typical mycorrhizal colonization often inhibits the growth but enhances the induced system resistance of non-host plants. Meanwhile, the host growth is also differentially affected, depending on plant and fungi species. Molecular analyses suggested that the AMF colonization to non-hosts is different from pathogenic and endophytic fungi colonization, and the hyphae in non-host roots may be alive and have some unknown functions. Thus we propose that non-host plants are also important CMNs players. Using non-mycorrhizal model species Arabidopsis, tripartite culture system and new technologies such as nanoscale secondary ion mass spectrometry and multi-omics, to study nutrient and signal transportation between host and non-host plants via CMNs may provide new insights into the mechanisms underlying benefits of intercropping and agro-forestry systems, as well as plant community establishment and stability.

RevDate: 2022-05-04
CmpDate: 2022-05-04

Knutson VL, TM Gosliner (2022)

The first phylogenetic and species delimitation study of the nudibranch genus Gymnodoris reveals high species diversity (Gastropoda: Nudibranchia).

Molecular phylogenetics and evolution, 171:107470.

Nudibranchs are charismatic marine gastropods that lack a shell in the adult stage. While most nudibranchs feed on sessile animals such as sponges, bryozoans, and cnidarians, the nudibranch genus Gymnodoris Stimpson, 1855 evolved a more active and predatory lifestyle, including sea slug predation, cannibalism, and oddly enough, fish-fin parasitism. At the beginning of our work, no phylogenetic hypothesis existed for the genus, nor a clear picture of how Gymnodoris is related to other nudibranchs. Here we set out to reconstruct Gymnodoris phylogeny, investigate species diversity, and clarify the status of the genus name Analogium, which had been proposed for members of the genus with a linear gill filament arrangement. We present the first phylogenetic hypothesis for Gymnodoris, reconstructed by maximum likelihood and Bayesian inference using two mitochondrial and two nuclear loci, with gill filament arrangement plotted on the phylogeny. The backbone of the phylogeny remains unresolved with theseloci, however, we found that Gymnodoris comprises three main well-supported clades, which we refer to as the "subornata", "citrina" and "varied" clade, the latter two clades being comprised of several well-supported subclades. The sister group to Gymnodoris is a clade including the genera Vayssierea and Lecithophorus. Based on ABGD and PTP species delimitation methods, we conservatively estimate 65-70 species comprise our dataset. We further estimate that approximately 81% of the species we sampled are undescribed, and note that a linear gill filament arrangement has evolved multiple times within the genus. Gymnodoris is only monophyletic when the species with a linear gill arrangement are included. Therefore, at this time, we agree with the synonymy of Analogium striata with Gymnodoris striata by Rudman and Darvell (1990) and that the genus name Analogium is warranted as a junior synonym of Gymnodoris. Given the extensive undescribed diversity, and lack of resolution at some of the nodes in the phylogeny, patterns of diversification in diet are impossible to discern at this time and will require a large effort to both describe Gymnodoris species diversity and the diets of these candidate species.

RevDate: 2022-05-05
CmpDate: 2022-05-05

Sousa KKA, Camargo RS, Caldato N, et al (2022)

The ideal habitat for leaf-cutting ant queens to build their nests.

Scientific reports, 12(1):4830.

Queens of Atta sexdens Forel (Hymenoptera: Formicidae) face biotic and abiotic environmental factors in the environment while establishing their nests. Biotic factors such as predation, microbial pathogens, successful symbiotic fungus regurgitation, excavation effort and abiotic factors such as radiant sunlight, temperature, density, and soil moisture exert selection pressures on ant queens. Biotic factors such as temperature and solar irradiation affect the survival of the initial colony differently, in different environments in the field. Queens of the leaf-cutting ant A. sexdens, were installed in sunny and shaded conditions to test this hypothesis. Two hundred A. sexdens queens were collected and individualized in two experimental areas (sunny and shaded), each in an experimental area (25 m2) in the center of a square (50 × 50 cm). Temperature, irradiance, nest depth, rainfall and queen mortality were evaluated. Atta sexdens colony development was better in the shaded environment, and the depth and volume of the initial chamber, fungus garden biomass and number of eggs, larvae, pupae and workers were greater. The queen masses were similar in both environments but mortality was higher in the sunny environment. The worse parameter values for A. sexdens nests in the sunny environment are due to the greater solar irradiance, increasing the variation range of the internal temperature of the initial chamber of the nest. On the other hand, the more stable internal temperature of this chamber in the shaded environment, is due to the lower incidence of solar irradiance, which is also more advantageous for queen survival and the formation and development of A. sexdens colonies. Shaded environments are a better micro habitat for nesting A. sexdens than sunny ones.

RevDate: 2022-05-05
CmpDate: 2022-05-05

Cunning R (2022)

Will coral reefs survive by adaptive bleaching?.

Emerging topics in life sciences, 6(1):11-15.

Some reef-building corals form symbioses with multiple algal partners that differ in ecologically important traits like heat tolerance. Coral bleaching and recovery can drive symbiont community turnover toward more heat-tolerant partners, and this 'adaptive bleaching' response can increase future bleaching thresholds by 1-2°C, aiding survival in warming oceans. However, this mechanism of rapid acclimatization only occurs in corals that are compatible with multiple symbionts, and only when the disturbance regime and competitive dynamics among symbionts are sufficient to bring about community turnover. The full scope of coral taxa and ecological scenarios in which symbiont shuffling occurs remains poorly understood, though its prevalence is likely to increase as warming oceans boost the competitive advantage of heat-tolerant symbionts, increase the frequency of bleaching events, and strengthen metacommunity feedbacks. Still, the constraints, limitations, and potential tradeoffs of symbiont shuffling suggest it will not save coral reef ecosystems; however, it may significantly improve the survival trajectories of some, or perhaps many, coral species. Interventions to manipulate coral symbionts and symbiont communities may expand the scope of their adaptive potential, which may boost coral survival until climate change is addressed.

RevDate: 2022-05-05
CmpDate: 2022-05-05

Cerrano C, Giovine M, L Steindler (2022)

Petrosia ficiformis (Poiret, 1789): an excellent model for holobiont and biotechnological studies.

Current opinion in biotechnology, 74:61-65.

RevDate: 2022-05-03

Jinkerson RE, Russo JA, Newkirk CR, et al (2022)

Cnidarian-Symbiodiniaceae symbiosis establishment is independent of photosynthesis.

Current biology : CB pii:S0960-9822(22)00590-5 [Epub ahead of print].

Photosynthesis shapes the symbiotic relationships between cnidarians and Symbiodiniaceae algae-with many cnidarian hosts requiring symbiont photosynthate for survival-but little is known about how photosynthesis impacts symbiosis establishment. Here, we show that during symbiosis establishment, infection, proliferation, and maintenance can proceed without photosynthesis, but the ability to do so is dependent on specific cnidarian-Symbiodiniaceae relationships. The evaluation of 31 pairs of symbiotic relationships (five species of Symbiodiniaceae in sea anemone, coral, and jellyfish hosts) revealed that infection can occur without photosynthesis. A UV mutagenesis method for Symbiodiniaceae was established and used to generate six photosynthetic mutants that can infect these hosts. Without photosynthesis, Symbiodiniaceae cannot proliferate in the sea anemone Aiptasia or jellyfish Cassiopea but can proliferate in the juvenile polyps of the coral Acropora. After 6 months of darkness, Breviolum minutum is maintained within Aiptasia, indicating that Symbiodiniaceae maintenance can be independent of photosynthesis. Manipulating photosynthesis provides insights into cnidarian-Symbiodiniaceae symbiosis.

RevDate: 2022-05-03

Sweany RR, DeRobertis CD, Kaller MD, et al (2022)

Intra-specific growth and aflatoxin inhibition responses to atoxigenic Aspergillus flavus: evidence of secreted, inhibitory substance(s) in biocontrol.

Phytopathology [Epub ahead of print].

The fungus Aspergillus flavus infects corn, peanut and cottonseed, and contaminates seeds with acutely poisonous and carcinogenic aflatoxin. Aflatoxin contamination is a perennial threat in tropical and sub-tropical climates. Non-aflatoxin producing isolates (atoxigenic) are deployed in fields to mitigate aflatoxin contamination. The biocontrol competitively excludes toxigenic A. flavus via direct replacement and thigmoregulated (touch) toxin inhibition mechanisms. To understand the broad-spectrum toxin inhibition, toxigenic isolates representing different mating types and sclerotia sizes were individually co-cultured with different atoxigenic biocontrol isolates. To determine if more inhibitory isolates had a competitive advantage to displace or touch inhibit toxigenic isolates, biomass accumulation rates were determined for each isolate. Finally, to determine if atoxigenic isolates could inhibit aflatoxin production without touch, atoxigenic isolates were grown separated from a single toxigenic isolate by a membrane. Atoxigenic isolates 17, Af36 and K49 had superior abilities to inhibit toxin production. Small (<400 µm) sclerotial, Mat1-1 isolates were not as completely inhibited as others by most atoxigenic isolates. As expected for both direct replacement and touch inhibition, the fastest growing atoxigenic isolates inhibited aflatoxin production the most, except for atoxigenic Af36 and K49. Aflatoxin production was inhibited when toxigenic and atoxigenic isolates were grown separately, especially by slow growing atoxigenic Af36 and K49. Additionally, fungus-free filtrates from atoxigenic cultures inhibited aflatoxin production. Toxin production inhibition without direct contact revealed secretion of diffusible chemical(s) as an additional biocontrol mechanism. Biocontrol formulations should be improved by identifying isolates with broad-spectrum, high inhibition capabilities and production of secreted inhibitory chemical(s).

RevDate: 2022-05-03
CmpDate: 2022-05-03

Balbuena MS, Broadhead GT, Dahake A, et al (2022)

Mutualism has its limits: consequences of asymmetric interactions between a well-defended plant and its herbivorous pollinator.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 377(1853):20210166.

Concern for pollinator health often focuses on social bees and their agricultural importance at the expense of other pollinators and their ecosystem services. When pollinating herbivores use the same plants as nectar sources and larval hosts, ecological conflicts emerge for both parties, as the pollinator's services are mitigated by herbivory and its larvae are harmed by plant defences. We tracked individual-level metrics of pollinator health-growth, survivorship, fecundity-across the life cycle of a pollinating herbivore, the common hawkmoth, Hyles lineata, interacting with a rare plant, Oenothera harringtonii, that is polymorphic for the common floral volatile (R)-(-)-linalool. Linalool had no impact on floral attraction, but its experimental addition suppressed oviposition on plants lacking linalool. Plants showed robust resistance against herbivory from leaf-disc to whole-plant scales, through poor larval growth and survivorship. Higher larval performance on other Oenothera species indicates that constitutive herbivore resistance by O. harringtonii is not a genus-wide trait. Leaf volatiles differed among populations of O. harringtonii but were not induced by larval herbivory. Similarly, elagitannins and other phenolics varied among plant tissues but were not herbivore-induced. Our findings highlight asymmetric plant-pollinator interactions and the importance of third parties, including alternative larval host plants, in maintaining pollinator health. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.


RJR Experience and Expertise


Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.


Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.


Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.


Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.


While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.


Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.


Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.


Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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In this comprehensive history of symbiosis theory--the first to be written--Jan Sapp masterfully traces its development from modest beginnings in the late nineteenth century to its current status as one of the key conceptual frameworks for the life sciences. The symbiotic perspective on evolution, which argues that "higher species" have evolved from a merger of two or more different kinds of organisms living together, is now clearly established with definitive molecular evidence demonstrating that mitochondria and chloroplasts have evolved from symbiotic bacteria. In telling the exciting story of an evolutionary biology tradition that has effectively challenged many key tenets of classical neo-Darwinism, Sapp sheds light on the phenomena, movements, doctrines, and controversies that have shaped attitudes about the scope and significance of symbiosis. Engaging and insightful, Evolution by Association will be avidly read by students and researchers across the life sciences.

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

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Curriculum Vitae for R J Robbins

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