Pseudomonas gessardii suppresses Xanthomonas vesicatoria through 4-Dodecylbenzene sulfonic acid interference with virulence proteins.

Endophytic bacteria reside asymptomatically inside host plant tissues and have the potential to protect the host plant from phytopathogens and enhance plant immunity. Exploration of the biocontrol mechanism of these beneficial bacteria can assure the development of eco-friendly pesticides for the effective management of phytopathogens. In our study, the isolated endophytic bacteria examined for its antimicrobial potential was identified as Pseudomonas gessardii strain RRBHU-1 based on 16 S rRNA gene sequence analysis. The crude extract containing the secondary metabolites from the P. gessardii strain RRBHU-1 demonstrated antagonistic activity against Xanthomonas vesicatoria, the causal organism of bacterial leaf spot disease in tomato plants. X. vesicatoria when treated with the RRBHU-1 extract showed disruption of the cell membrane, significant ROS production, and substantial antibiofilm activity. The extract separated through TLC and RP-HPLC and characterized using FT-IR, NMR, and HRAMS, and was identified as 4-Dodecylbenzene sulfonic acid (4-DBSA). This study is the first report on the presence of 4-DBSA in the Pseudomonas genera. In silico studies revealed stable interactions and high binding energies of 4-DBSA and the proteins directly involved in Xanthomonas virulence. This study suggests the possible utilization of P. gessardii strain RRBHU-1 as biopesticides against X. vesicatoria, encompassing sustainable agricultural practices.