Project description:The rate, timing, and mode of species dispersal is recognized as a key driver of the structure and function of communities of macroorganisms, and may be one ecological process that determines the diversity of microbiomes. Many previous studies have quantified the modes and mechanisms of bacterial motility using monocultures of a few model bacterial species. But most microbes live in multispecies microbial communities, where direct interactions between microbes may inhibit or facilitate dispersal through a number of physical (e.g., hydrodynamic) and biological (e.g., chemotaxis) mechanisms, which remain largely unexplored. Using cheese rinds as a model microbiome, we demonstrate that physical networks created by filamentous fungi can impact the extent of small-scale bacterial dispersal and can shape the composition of microbiomes. From the cheese rind of Saint Nectaire, we serendipitously observed the bacterium Serratia proteamaculans actively spreads on networks formed by the fungus Mucor. By experimentally recreating these pairwise interactions in the lab, we show that Serratia spreads on actively growing and previously established fungal networks. The extent of symbiotic dispersal is dependent on the fungal network: diffuse and fast-growing Mucor networks provide the greatest dispersal facilitation of the Serratia species, while dense and slow-growing Penicillium networks provide limited dispersal facilitation. Fungal-mediated dispersal occurs in closely related Serratia species isolated from other environments, suggesting that this bacterial-fungal interaction is widespread in nature. Both RNA-seq and transposon mutagenesis point to specific molecular mechanisms that play key roles in this bacterial-fungal interaction, including chitin utilization and flagellin biosynthesis. By manipulating the presence and type of fungal networks in multispecies communities, we provide the first evidence that fungal networks shape the composition of bacterial communities, with Mucor networks shifting experimental bacterial communities to complete dominance by motile Proteobacteria. Collectively, our work demonstrates that these strong biophysical interactions between bacterial and fungi can have community-level consequences and may be operating in many other microbiomes.
Project description:High ambient temperature regulated the plant systemic response to the beneficial endophytic fungus Serendipita indica. Most plants in nature establish symbiotic associations with endophytic fungi in soil. Beneficial endophytic fungi induce a systemic response in the aboveground parts of the host plant, thus promoting the growth and fitness of host plants. Meanwhile, temperature elevation from climate change widely affects global plant biodiversity as well as crop quality and yield. Over the past decades, great progresses have been made in the response of plants to high ambient temperature and to symbiosis with endophytic fungi. However, little is known about their synergistic effect on host plants. The endophytic fungus Serendipita indica colonizes the roots of a wide range of plants, including Arabidopsis. Based on the Arabidopsis-S. indica symbiosis experimental system, we analyzed the synergistic effect of high ambient temperature and endophytic fungal symbiosis on host plants. By transcriptome analysis, we found that DNA replication-related genes were significantly upregulated during the systemic response of Arabidopsis aboveground parts to S. indica colonization. Plant hormones, such as jasmonic acid (JA) and ethylene (ET), play important roles in plant growth and systemic responses. We found that high ambient temperature repressed the JA and ET signaling pathways of Arabidopsis aboveground parts during the systemic response to S. indica colonization in roots. Meanwhile, PIF4 is the central hub transcription factor controlling plant thermosensory growth under high ambient temperature in Arabidopsis. PIF4 is also involving JA and/or ET signaling pathway. We found that PIF4 target genes overlapped with many differentially expressed genes (DEGs) during the systemic response, and further showed that the growth promotion efficiency of S. indica on the pif4 mutant was higher than that on the wild type plants.
Project description:The goal of this study was to identify fungal gene expression changes during early stages of symbiosis establishment with its Burkholderia endosymbionts. Results: Leveraging this RNA-seq dataset we identified fungal genes utilized for symbiosis establishment with bacteria.
Project description:Background: While the luminal microbiome composition in the human cervicovaginal tract has been defined, the presence and impact of tissue-adherent ectocervical microbiota remain incompletely understood. Studies of luminal and tissue-associated bacteria in the gastrointestinal tract suggest that they may have distinct roles in health and disease. Here, we performed a multi-omics characterization of paired luminal and tissue samples collected from a clinically well-characterized cohort of Kenyan women. Results: We identified a tissue-adherent bacterial microbiome, with a higher alpha diversity than the luminal microbiome, in which dominant genera overall included Gardnerella and Lactobacillus, followed by Prevotella, Atopobium, and Sneathia. About half of the L. iners dominated luminal samples had a corresponding Gardnerella dominated tissue microbiome. Broadly, the tissue-adherent microbiome was associated with fewer differentially expressed host genes than the luminal microbiome. Gene set enrichment analysis revealed that L. crispatus-dominated tissue-adherent communities were associated with protein translation and antimicrobial activity, whereas a highly diverse microbiome was associated with epithelial remodeling and pro-inflammatory pathways. Communities dominated by L. iners and Gardnerella were associated with low host transcriptional activity. Tissue-adherent microbiomes dominated by Lactobacillus and Gardnerella correlated with host protein profiles associated with epithelial barrier stability, and with a more pro-inflammatory profile for the Gardnerella-dominated microbiome group. Tissue samples with a highly diverse composition had a protein profile representing cell proliferation and pro-inflammatory activity. Conclusion: We identified ectocervical tissue-adherent bacterial communities in all study participants. These communities were distinct from cervicovaginal luminal microbiota in a significant proportion of individuals. This difference could possibly explain that L. iners dominant luminal communities have a high probability of transitioning to high diverse bacterial communities including high abundance of Gardnerella. By performing integrative multi-omics analyses we further revealed that bacterial communities at both sites correlated with distinct host gene expression and protein levels. The tissue-adherent bacterial community is similar to vaginal biofilms that significantly impact women’s reproductive and sexual health.
2023-02-10 | GSE194276 | GEO
Project description:Rhizosphere and endophytic fungal communities
Project description:To exploite S. sclerotiorum to identify differential fungal responses leading to either an endophytic or a pathogenic lifestyle during colonization of both asymptomatic host and symptomatic host We then performed gene expression profiling analysis using data obtained from RNA-seq of 9 different samples after 2 days.