Omics-based insights into endophytic Bacillus subtilis (TN FL 158) for blister blight management in Camellia sinensis

Blister blight of tea (Camellia sinensis), caused by Exobasidium vexans, is one of the most destructive foliar diseases in South India, with an incidence of up to 68% and yield losses approaching 50%. In the present study, an endophytic bacterial isolate, Bacillus subtilis (TN FL 158), obtained from the flower of C. sinensis, was evaluated for its in vitro antagonistic potential against E. vexans along with genome mining, metabolite profiling and host transcriptome analysis. Scanning electron microscopy indicated the association of bacterial cells with treated leaf and twig tissues following foliar application. The strain suppressed basidiospore germination by 93.39% (5.56% germination compared to 84% in the control) and exhibited siderophore production along with cellulase, protease and amylase activities. Whole genome sequencing yielded a 3.96 Mb genome with a GC content of 43.68%, comprising 3,765 protein-coding genes and several biosynthetic gene clusters associated with antimicrobial secondary metabolites such as fengycin, surfactin, iturin, bacilysin, subtilosin A, pulcherriminic acid and bacillibactin. Comparative genomic analysis revealed 84 singleton genes and an open pan-genome structure. Gas chromatography-mass spectrometry detected several non-volatile metabolites and volatile organic compounds in the bacterial culture. Transcriptome profiling of tea plants treated with B. subtilis (TN FL 158) and challenged with E. vexans indicated differential expression patterns of defense-related genes. Collectively, these findings suggest that B. subtilis (TN FL 158) may represent a promising candidate for further evaluation as a potential biocontrol agent for blister blight management in Camellia sinensis.

The online version contains supplementary material available at 10.1007/s13205-026-04829-5.