Metabolite Interactions Mediate Beneficial Alliances BetweenBacillusandTrichodermafor Effective Fusarium Wilt Control

Bacteria-Fungi Interactions play a crucial role in soil nutrient cycling and plant disease suppression.BacillusandTrichodermaexhibit antagonism when inoculated on laboratory media, global soil sample analysis reveals a positive correlation between these two genera in addition to enhanced plant-pathogenFusarium oxysporum(FOC) suppression and plant growth promotion. Here, we depict a complexity of interactions in a cross-kingdom consortia ofBacillus velezensisandTrichoderma guizhouense. Transcriptomic profiling revealed that in the presence of fungi, the key stress sigma factor ofB. velezensisactivates expression of biosynthetic genes for antimicrobial secondary metabolite production. Among these, surfactin induces T22azaphilone production inT. guizhouensethat hinders oxidative stress. Both surfactin and T22azaphilone contribute toBacillusandTrichodermamaintenance in soil in the presence of FOC. Finally, FOC-secreted fusaric acid temporarily inhibitsB. velezensisgrowth while it is efficiently degraded byT. guizhouense. These metabolite-mediated interactions reveal how competing soil microorganisms could form effective alliances that ultimately enhance plant protection against soil-borne pathogens.