Date: 26th August 2020
Title: Reprograming of host and microbial metabolisms during beneficial plant-microbe interaction
Location: Remotely via Zoom
Host: Michael Wrzaczek
Abstract: Beneficial microbes can enhance plant growth and provide abiotic and biotic stress tolerance to plants, but their underlying mechanisms are poorly understood. We focused on the mechanisms how beneficial microbes can enhance salt stress tolerance in crops and Arabidopsis. We found that multiple beneficial endophytic bacteria enhance salt tolerance by reprograming the plant root and shoot ion transporter systems of Na+ and K+. Detailed inspection of the interaction of Arabidopsis with the root endophyte Enterobacter sp. SA187 showed massive changes in bacterial gene expression in chemotaxis, flagellar biosynthesis, quorum sensing and biofilm formation. Importantly, Arabidopsis induced the sulfur metabolism of SA187 resulting in the production of a small sulfur metabolite which regulates the ethylene signaling pathway of the host plant. These conclusions are supported by GWAS analysis showing that Arabidopsis mutants deficient in ethylene signaling lose the beneficial interaction with SA187 and are hypersensitive to salt stress. Comparing the interaction of multiple beneficial bacterial species with various crops indicates that endophyte association and entry into plants are highly conserved and rely on novel active penetration mechanisms. In summary, beneficial microbes represent a cheap and efficient technology with an enormous potential to secure food production worldwide, and an in-depth understanding of the steps involved in plant colonization should help to develop efficient strategies for using this technology in future sustainable agriculture.
Professor Hirt's research interests are in signal transduction and the molecular communication mechanisms between microorganisms and plants.