Enhanced Endophytic Colonization of Flavobacterium Promotes Plant Resistance to Fusarium Wilt

Microbial taxa in the soil microbiome with specific ecological functions play crucial roles in plant health. Flavobacterium is found closely associated with physiological functions that promote plant growth and enhance disease resistance. While cooperative interactions mediated by metabolite exchange can stabilize microbial consortia, the specific interactions between these consortia and plants remain understudied, particularly regarding their application in plant disease control. Here, we isolate a natural microbial consortium comprising Achromobacter, Flavobacterium, and Bacillus strains from cucumber rhizosphere soil, and identify the Flavobacterium strain as a methionine auxotroph. This study reveals the metabolic interactions among strains within a cross-feeding-based consortium. The Achromobacter and Bacillus primarily metabolize carbon and nitrogen sources, respectively, whereas the relevant genes in the Flavobacterium are significantly downregulated. The consortium develops significantly enhanced biofilms with a distinct stratified architecture, facilitating root endophytic colonization by Achromobacter and Flavobacterium. Endophytic Flavobacterium induces systemic resistance in plants, thereby enhancing resistance against phytopathogenic fungal infections. Our findings reveal a novel ecological strategy employed by auxotrophic Flavobacterium species for both microbial interactions and root endophytic colonization and provide a theoretical foundation for microbial consortium-based microbial inoculants in plant disease management.