Shared Secondary Metabolites Between Salicornia brachiata and Its Bacillus Endophytes Reveal a Cooperative Chemical Defense

This study explores the chemical ecology of the halophytic plant Salicornia brachiata and its associated Bacillus endophytes using LC‐MS‐based metabolomics. A total of 43 Bacillus strains were isolated and screened for the production of bioactive lipopeptides, with 26 strains showing both lipopeptide production and antimicrobial activity, particularly against Mycobacterium smegmatis MTCC6. Fermentation of a potent endophyte, Bacillus subtilis NPRoot‐3, yielded purified surfactins and fengycins, which displayed significant inhibitory activity with low IC 50 values against Mycobacterium smegmatis . LC‐MS analysis of aqueous and methanolic extracts of S. brachiata revealed molecular features putatively corresponding to surfactins, fengycins, and bacillibactins, indicating the presence of similar bioactive compounds in both the host plant and its endophytic microbiome. These findings suggest that the antimycobacterial properties of S. brachiata may be partly attributed to metabolites produced by its endophytes. Overall, this study highlights cooperative defense mechanisms between the plant and its endophytes, confirms the role of endophyte‐derived secondary metabolites in shaping plant bioactivity and offers promising leads for the discovery of novel antimycobacterial agents.