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:Bacterial mock community of a microalga
Project description:In this study we developed metaproteomics based methods for quantifying taxonomic composition of microbiomes (microbial communities). We also compared metaproteomics based quantification to other quantification methods, namely metagenomics and 16S rRNA gene amplicon sequencing. The metagenomic and 16S rRNA data can be found in the European Nucleotide Archive (Study number: PRJEB19901). For the method development and comparison of the methods we analyzed three types of mock communities with all three methods. The communities contain between 28 to 32 species and strains of bacteria, archaea, eukaryotes and bacteriophage. For each community type 4 biological replicate communities were generated. All four replicates were analyzed by 16S rRNA sequencing and metaproteomics. Three replicates of each community type were analyzed with metagenomics. The "C" type communities have same cell/phage particle number for all community members (C1 to C4). The "P" type communities have the same protein content for all community members (P1 to P4). The "U" (UNEVEN) type communities cover a large range of protein amounts and cell numbers (U1 to U4). We also generated proteomic data for four pure cultures to test the specificity of the protein inference method. This data is also included in this submission.