Project description:Chemical signaling in the plant microbiome can have drastic effects on microbial community structure, and on host growth and development. Previously, we demonstrated that the auxin metabolic signal interference performed by the bacterial genus Variovorax via a novel auxin degradation locus was essential for maintaining stereotypic root development in an ecologically-relevant bacterial synthetic community. Here, we dissect the Variovorax auxin degradation locus to define the genes necessary and sufficient for indole-3-acetic acid (IAA) degradation and signal interference. We determine the crystal structures and binding properties of the operon’s MarR-family repressor with IAA and other auxins. We identify auxin-degradation operons across the bacterial tree of life and define two distinct types based on gene content and metabolic products: iac-like and iad-like. We solve the structures of MarRs from representatives of each auxin degradation operon type, establishing that each have distinct IAA binding pockets. Comparison of representative IAA degrading strains from diverse bacterial genera show that while all degrade IAA, only strains containing iad-like auxin degrading operons interfere with auxin signaling in a complex synthetic community context. This suggests that iad-like operon containing strains, including Variovorax species, play a key ecological role in modulating auxins in the plant microbiome.
2022-08-11 | GSE210968 | GEO
Project description:Archaeal Community under LCFAs degradation
| PRJNA732540 | ENA
Project description:Bacterial community response during PAH degradation
Project description:Coral bleaching and coral reef degradation become severe as the surface seawater temperature rises. Much research to date has focused on the bacterial community composition properties within the coral holobiont, but less attention has been paid to the interactions of bacteria and corals under thermal stress. We investigated the changes of coral symbiotic bacteria and metabolites under thermal stress, and analyzed the internal relationship between bacteria and metabolites as well as their relationship with coral health. We found obvious signs of coral bleaching after heating treatment, and the interaction within symbiotic bacterial community became closer. The coral symbiotic bacterial community and metabolites changed significantly under thermal stress, and bacteria such as Flavobacterium, Shewanella and Psychrobacter increased significantly. Bacteria associated with stress tolerance, biofilm formation and mobile elements decreased, and bacterial DMSP metabolism increased slightly after heating treatment. Differential metabolites in corals after heating treatment were associated with cell cycle regulation and antioxidant. This study revealed the correlation between differential metabolites and bacterial community composition changes in corals under thermal stress, and providing valuable insight on metabolomics research of corals.
Project description:The gut microbiome is significantly altered in inflammatory bowel diseases, but the basis of these changes is not well understood. We have combined metagenomic and metatranscriptomic profiling of the gut microbiome to assess changes to both bacterial community structure and transcriptional activity in a mouse model of colitis. Gene families involved in microbial resistance to oxidative stress, including Dps/ferritin, Fe-dependent peroxidase and glutathione S-transferase, were transcriptionally up-regulated in colitis, implicating a role for increased oxygen tension in gut microbiota modulation. Transcriptional profiling of the host gut tissue and host RNA in the gut lumen revealed a marked increase in the transcription of genes with an activated macrophage and granulocyte signature, suggesting the involvement of these cell types in influencing microbial gene expression. Down-regulation of host glycosylation genes further supports a role for inflammation-driven changes to the gut niche that may impact the microbiome. We propose that members of the bacterial community react to inflammation-associated increased oxygen tension by inducing genes involved in oxidative stress resistance. Furthermore, correlated transcriptional responses between host glycosylation and bacterial glycan utilisation support a role for altered usage of host-derived carbohydrates in colitis. Complementary transcription profiling data from the mouse hosts have also been deposited at ArrayExpress under accession number E-MTAB-3590 ( http://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-3590/ ).