A smooth vetch ( Vicia villosa var.) strain endogenous to the broad-spectrum antagonist Bacillus siamensis JSZ06 alleviates banana wilt disease

wilt, caused by f. sp. Tropical Race 4 ( TR4), poses a significant threat to banana production globally, thereby necessitating effective biocontrol methods to manage this devastating disease. This study investigates the potential of strain JSZ06, isolated from smooth vetch, as a biocontrol agent against TR4. To this end, we conducted a series of and experiments to evaluate the antifungal activity of strain JSZ06 and its crude extracts. Additionally, genomic analyses were performed to identify antibiotic synthesis genes, while metabolomic profiling was conducted to characterize bioactive compounds. The results demonstrated that strain JSZ06 exhibited strong inhibitory activity against TR4, significantly reducing mycelial growth and spore germination. Moreover, scanning and transmission electron microscopy revealed substantial ultrastructural damage to TR4 mycelia treated with JSZ06 extracts. Genomic analysis identified several antibiotic synthesis genes, and metabolomic profiling revealed numerous antifungal metabolites. Furthermore, in pot trials, the application of JSZ06 fermentation broth significantly enhanced banana plant growth and reduced disease severity, achieving biocontrol efficiencies of 76.71% and 79.25% for leaves and pseudostems, respectively. In conclusion, JSZ06 is a promising biocontrol agent against wilt in bananas, with its dual action of direct antifungal activity and plant growth promotion underscoring its potential for integrated disease management strategies.