Poster
Huei-Hsuan TSAI
Postdoctoral researcher
Department of Plant Molecular Biology, University of Lausanne
Lausanne, Vaud, Switzerland
Yuanjie Tang
Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences
Shanghai, Shanghai, China (People's Republic)
Valérie Dénervaud Tendon
Department of Plant Molecular Biology, University of Lausanne
Lausanne, Vaud, Switzerland
Jia Pang
Department of Plant Molecular Biology, University of Lausanne
Lausanne, Vaud, Switzerland
Kathrin Wippel
University of Amsterdam
Amsterdam, Noord-Holland, Netherlands
Jordan Vacheron
Department of Fundamental Microbiology, University of Lausanne
Lausanne, Vaud, Switzerland
Christoph Keel
Department of Fundamental Microbiology, University of Lausanne
Lausanne, Vaud, Switzerland
Tonni Andersen
Max Planck Institute for Plant Breeding
Köln, Nordrhein-Westfalen, Germany
Niko Geldner
Professor
Universite de Lausanne
Lausanne, Vaud, Switzerland
Feng Zhou (he/him/his)
Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences
Shanghai, CHINA
Plant roots shape microbial communities through exudates, influencing plant health and stress adaptation. However, how specific exudates drive spatial colonization patterns remains poorly understood. We uncover a key role for the Casparian strip, an endodermal diffusion barrier, in restricting nutrient leakage, directly influencing microbial colonization patterns. Using the Arabidopsis thaliana sgn3 myb36 mutant, which has a defective endodermal barrier, we observed enhanced bacteria root colonization, attributed to enhanced bacterial chemotaxis and proliferation. Metabolomic analysis of wild-type and sgn3 myb36 root exudates revealed elevated levels of amino acids, specifically glutamine, in the latter. Bacterial attraction to sgn3 myb36 roots and wild-type leakage sites, such as elongation zones and lateral root emergence sites, depends on chemotaxis and amino acid sensing, as bacteria mutants impaired in these processes exhibited reduced colonization. To validate the role of glutamine in attracting bacteria to leakage sites in wild-type roots, we developed bacterial glutamine-inducible reporters, allowing high spatial resolution visualization of bacterial metabolic states along the root. Our findings underscore the importance of tight control of nutrient provision to the rhizosphere, and provide insights into the basis of bacterial colonization patterns. In addition, we establish transient metabolite leakage from the vasculature as a novel method of root exudate formation.