Hydrolase P1 in Bacillus velezensis HN-2 confers tobacco resistance by delaying TMV infection.

BACKGROUND

Tobacco is a critical cash crop globally, contributing significantly to government revenues. However, its production is severely threatened by tobacco mosaic virus (TMV), which causes substantial yield and quality losses, leading to economic damage. Given the limited efficacy of chemical controls, biological control methods have gained prominence. Bacillus spp. are recognized as effective agents for plant disease management. In prior research, Bacillus velezensis HN-2 demonstrated promising traits for inducing plant resistance.

RESULTS

This study revealed that the total protein extract from B. velezensis HN-2 triggers the production of reactive oxygen species, upregulates antioxidant enzymes, activates immune-related protein genes, and induces systemic resistance in plants. Its effectiveness surpassed that of benzothiadiazole and Dufulin in delaying TMV invasion. Further analysis identified a specific hydrolase protein within the total protein extract that plays a key role in the observed antiviral activity. Exogenous expression and functional assays confirmed that this hydrolase, designated P1, is the primary active protein in B. velezensis HN-2 responsible for delaying TMV infection.

CONCLUSION

Hydrolase protein P1 acts as an elicitor to induce systemic resistance in the tobacco plant against TMV Infection. These findings provide an experimental foundation for the application of B. velezensis HN-2 in biological control strategies and offer theoretical insights into the use of Bacillus-derived proteins for TMV management. © 2025 Society of Chemical Industry.