Project description:Drought is one of the most detrimental environmental factors that adversely affect crop production, thus jeopardizing food supplies for a growing world population. Over the past years, it has become evident that microorganisms associated with plants can enhance drought tolerance. However, the specific genetic and molecular mechanisms underpinning bacterial induction of drought tolerance in plants are still largely unknown. In our work, we have shown that a root endophytic Flavobacterium sp. 98 confers significant drought tolerance to Arabidopsis thaliana without compromising growth and yield. Here, we compared the transcriptome of Arabidopsis seedlings inoculated with Flavobacterium or mock (time series) to identify transcription reprograming induced by Flavo in plants.
Project description:The plant hemicellulose xyloglucan (XyG) is secreted from the roots of numerous plant species, including cereals, and contributes towards soil aggregate formation in terrestrial systems. Whether XyG represents a key nutrient for plant-associated bacteria is unclear. The phylum Bacteroidota are abundant in the plant microbiome and provide several beneficial functions for their host. However, the metabolic and genomic traits underpinning their success remain poorly understood. Here, we employed whole-cell proteomics to determine the molecular mechanisms responsible for xyloglucan utilisation in two model Flavobacterium species, Flavobacterium johnsoniae DSM2064 and Flavobacterium sp. OSR005. We identified the occurrence of a distinct and conserved gene cluster, referred to as the Xyloglucan Utilisation Loci (XyGUL). Flavobacterium XyGUL is a hybrid of the molecular machinery found in gut Bacteroides spp., Cellvibrio japonicus, and the plant pathogen Xanthomonas. Combining protein biochemistry, computational modelling and phylogenetics, we identified a mutation in the enzyme required for initiating hydrolysis of the XyG polysaccharide, an outer membrane endoxyloglucanase glycoside hydrolase family 5 subfamily 4 (GH5_4), which enhances activity towards XyG.
