Synthetic Community Driven by a Keystone Rhizosphere Bacterium Suppresses Whitefly‐Mediated Begomovirus Transmission via the Jasmonate Signaling Pathway in Tomato

Tomato production is threatened by the combined stress of whiteflies and the whitefly-transmitted Tomato yellow leaf curl virus (TYLCV). Although the rhizosphere microbiome plays a critical role in plant defense, the rational assembly strategy and underlying mechanisms of a synthetic microbial community (SynCom) targeting this insect-virus complex remain unclear. Here, leveraging the beneficial soil legacy induced by Beauveria bassiana, we constructed an eight-strain synthetic community through multi-omics analysis, soil incubation, and root exudate chemotaxis assays. One-strain knockout experiments confirmed that strain N2 is the keystone species driving the biocontrol function. Through supernatant cross-culture assays, we further refined this consortium into an optimized synthetic community (OptSynM) consisting of the single keystone strain and four helper strains. Bioassays demonstrated that OptSynM significantly reduced whitefly fitness and suppressed TYLCV accumulation in tomato plants. Within the consortium, the helper strains enhanced the rhizosphere colonization of N2 by promoting its growth and biofilm formation. Mechanistically, OptSynM activated host systemic immunity via the jasmonic acid signaling pathway. Furthermore, OptSynM maintained robust biocontrol efficacy in pot trials conducted with natural agricultural soil. Our findings highlight the practical promise of microbiome-based interventions and provide a strategic framework for using synthetic microbial communities to facilitate sustainable agricultural practices.