Project description:Algal bacterial interactions in phycosphere microbial communities have important implications for the stability and productivity of algal biofuel systems, and algal metabolites are important mediators of those interactions. We characterized exometabolites and cell associated metabolites from the model diatom Phaeodactylum tricornutum across different growth stages.
2022-02-02 | ST002077 | MetabolomicsWorkbench
Project description:Study on microbial diversity of raw swine wastewater and algal-bacterial systems
Project description:Coral reefs are declining globally. Temperature anomalies disrupt coral-algal symbioses at the molecular level, causing bleaching and mortality events. In terrestrial mutualisms, diversity in pairings of host and symbiont individuals (genotypes) results in ecologically and evolutionarily relevant stress response differences. The extent to which such intraspecific diversity provides functional variation in coral-algal systems is unknown. Here we assessed functional diversity among unique pairings of coral and algal individuals (holobionts). We targeted six genetically distinct Acropora palmata coral colonies that all associated with a single, clonal Symbiodinium ‘fitti’ strain in a natural common garden. No other species of algae or other strains of S. ‘fitti’ could be detected in host tissues. When colony branches were experimentally exposed to cold stress, host genotype influenced the photochemical efficiency of the symbiont strain, buffering the stress response to varying degrees. Gene expression differences among host individuals with buffered vs. non-buffered symbiont responses included biochemical pathways that mediate iron availability and oxygen stress signaling—critical components of molecular interactions with photosynthetic symbionts. Spawning patterns among hosts reflected symbiont performance differences under stress. These data are some of the first to indicate that genetic interactions below the species level affect coral holobiont performance. Intraspecific diversity serves as an important but overlooked source of physiological variation in this system, contributing raw material available to natural selection. Note: in the final publication, only ambient and cold treatments are discussed, but there was an additional hot treatment for each genotype at 34C. Most colonies expired after 6 hours, so PAM data could not be collected. The microarray data from 3.5 hours are included here.
2015-10-01 | GSE50926 | GEO
Project description:Symbiotic systems of scale insects
Project description:Emergence of the symbiotic lifestyle fostered the immense diversity of all ecosystems on Earth, but symbiosis plays a particularly remarkable role in marine ecosystems. Photosynthetic dinoflagellate endosymbionts power reef ecosystems by transferring vital nutrients to their coral hosts. The mechanisms driving this symbiosis, specifically those which allow hosts to discriminate between beneficial symbionts and pathogens, are not well understood. Here, we uncover that host immune suppression is key for dinoflagellate endosymbionts to avoid elimination by the host using a comparative, model systems approach. Unexpectedly, we find that the clearance of non-symbiotic microalgae occurs by non-lytic expulsion (vomocytosis) and not intracellular digestion, the canonical mechanism used by professional immune cells to destroy foreign invaders. We provide evidence that suppression of TLR signalling by targeting the conserved MyD88 adapter protein has been co-opted for this endosymbiotic lifestyle, suggesting that this is an evolutionarily ancient mechanism exploited to facilitate symbiotic associations ranging from coral endosymbiosis to the microbiome of vertebrate guts.
Project description:Emergence of the symbiotic lifestyle fostered the immense diversity of all ecosystems on Earth, but symbiosis plays a particularly remarkable role in marine ecosystems. Photosynthetic dinoflagellate endosymbionts power reef ecosystems by transferring vital nutrients to their coral hosts. The mechanisms driving this symbiosis, specifically those which allow hosts to discriminate between beneficial symbionts and pathogens, are not well understood. Here, we uncover that host immune suppression is key for dinoflagellate endosymbionts to avoid elimination by the host using a comparative, model systems approach. Unexpectedly, we find that the clearance of non-symbiotic microalgae occurs by non-lytic expulsion (vomocytosis) and not intracellular digestion, the canonical mechanism used by professional immune cells to destroy foreign invaders. We provide evidence that suppression of TLR signalling by targeting the conserved MyD88 adapter protein has been co-opted for this endosymbiotic lifestyle, suggesting that this is an evolutionarily ancient mechanism exploited to facilitate symbiotic associations ranging from coral endosymbiosis to the microbiome of vertebrate guts.
Project description:Rhizobia are soil bacteria that can associate with some legumes and participate in symbiotic nitrogen fixation. Bacterial CspA family members are small, single stranded nucleic acid binding proteins. Differentiation of rhizobial bacteria from a free-living to symbiotic state within legume root nodules follows a massive re-programming of bacterial gene expression. Here, the role of Sinorhizobium meliloti CspA family members in symbiotic development with Medicago sativa (alfalfa) was investigated. We defined expression patterns of CspA family members, identified CspA interacting RNAs, and investigated phenotypes and transcriptional defects associated with cspA deletion strains. We propose that these proteins affect rhizobial physiology through their global control of the cellular RNA secondary structure strength environment and through specific modulation of small non-coding RNA (sRNA) structures involved in cis-regulation of stress responsive sigma factor expression. This work describes an RNA structure mediated mechanism important for bacterial stress adaptation and symbiotic development within a plant host.
Project description:Rhizobia are soil bacteria that can associate with some legumes and participate in symbiotic nitrogen fixation. Bacterial CspA family members are small, single stranded nucleic acid binding proteins. Differentiation of rhizobial bacteria from a free-living to symbiotic state within legume root nodules follows a massive re-programming of bacterial gene expression. Here, the role of Sinorhizobium meliloti CspA family members in symbiotic development with Medicago sativa (alfalfa) was investigated. We defined expression patterns of CspA family members, identified CspA interacting RNAs, and investigated phenotypes and transcriptional defects associated with cspA deletion strains. We propose that these proteins affect rhizobial physiology through their global control of the cellular RNA secondary structure strength environment and through specific modulation of small non-coding RNA (sRNA) structures involved in cis-regulation of stress responsive sigma factor expression. This work describes an RNA structure mediated mechanism important for bacterial stress adaptation and symbiotic development within a plant host.
Project description:Animal regeneration requires coordinated responses of many cell types throughout the animal body. In animals carrying endosymbionts, cells from the other species may also participate in regeneration, but how cellular responses are integrated across species is yet to be unraveled. Here, we study the acoel Convolutriloba longifissura, which hosts symbiotic Tetraselmis green algae and can regenerate entire bodies from small tissue fragments. We show that animal injury leads to a decline in the photosynthetic efficiency of the symbiotic algae and concurrently induces upregulation of a cohort of photosynthesis-related genes. A deeply conserved animal transcription factor, runt, is induced after injury and required for the acoel regeneration. Knockdown of runt also dampens algal transcriptional responses to the host injury, particularly in photosynthesis related pathways, and results in further reduction of photosynthetic efficiency post-injury. Our results suggest that the runt-dependent animal regeneration program coordinates wound responses across the symbiotic partners and regulates photosynthetic carbon assimilation in this metaorganism.