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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-053 - Hydathode immunity upon infection by Xanthomonas bacteria

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Crop resistance genetics and genomics

Xanthomonas bacteria represent a large group of phytopathogens that infect many economically important crops worldwide. Vascular systemic infection through plant xylem is an ancestral Xanthomonas trait whose genetic bases on both pathogen and plant sides remain poorly understood. Hydathodes are plant organs present on leaf margins which mediate guttation, i.e. the release of excess fluid derived from the xylem sap. Hydathodes thus represent a direct infection route used by several xylem-infecting pathogens. Here, we propose to present hydathode anatomy, its infection by Brassica-infecting Xanthomonas and report on plant genes important for immunity. To this end, we screened a collection of 900 Arabidopsis EMS homozygous mutant (HEM) lines available at the Versailles Stock Centre. The interest of such compact and fully-sequenced mutant collection for gene function discovery will be presented. Thanks to this screen, we were able to link hydathode number at leaf margins and immunity to Xanthomonas. Our results point towards the key role of water availability for the definition of plant tissue specificity of Xanthomonas and the associated disease symptom development.