Integrative Genomic and Metabolomic Analysis of Terribacillus aidigensis KB25 Highlights Its Antifungal Activity against Phytophthora infestans and Adaptive Responses to Salt Stress

ABSTRACT This study characterizes Terribacillus aidigensis strain KB25, a novel halotolerant isolate from a thermal spring, exhibiting potent antifungal activity against the late blight pathogen Phytophthora infestans . Whole-genome sequencing and electron microscopy revealed significant physiological adaptations to salt stress and a rich genomic repertoire encoding secondary metabolites. Metabolomic profiling of the bacteria-fungus interaction demonstrated upregulated cofactor biosynthesis and energy metabolism, specifically identifying antimicrobial terpene derivatives as key inhibitory agents. Complementary molecular docking studies provided mechanistic insights, predicting high-affinity binding between bacterial sporulenol and the P. infestans RxLR effector. Notably, the analysis indicated a strong structural interaction between the bacterial ABC-type proline/glycine betaine permease and the glutamate receptor, suggesting a mechanism for mediating plant stress tolerance. These findings validate the dual efficacy of KB25 which indicates direct pathogen suppression via bioactive metabolite secretion and the potential modulation of host stress signalling. Integrated genomic-metabolomic analysis was also proved our findings. Consequently, T. aidigensis KB25 represents a promising, sustainable biocontrol agent for managing late blight, particularly within saline agro-ecosystems. Graphical abstract