Unlocking the antibacterial potential of berberine-thioether derivatives against plant canker

Plant diseases have long posed a severe threat to global agricultural production. Among these, kiwifruit canker and citrus canker-caused by Pseudomonas syringae pv. actinidiae (Psa) and Xanthomonas axonopodis pv. citri (Xac), respectively-are quarantine diseases that lack effective green control agents.

This work synthesized novel berberine-thioether derivatives, most of which showed potent antibacterial activity against Psa and Xac. The half-effective concentration values of compounds B-4 - B-6 against Xac (0.29, 0.37, and 0.39 μg mL^-1, respectively) and of A-1 - A-6 against Psa (6.54, 3.98, 0.33, 0.36, 0.29, and 3.37 μg mL^-1, respectively) are markedly lower than those of berberine and thiodiazole-copper (a commercial drug). Notably, compounds A-4 and B-4 can alter biofilm formation, increase reactive oxygen species levels, disrupt bacterial morphology, interact with DNA, and induce bacterial necrosis. Compound A-4 exhibits effective control activity against kiwifruit canker, with average protective and curative efficiency of 71.39% and 61.60%, respectively. Both compounds also showed great protective activity against citrus canker.

In summary, we reported novel berberine-thioether derivatives that demonstrate promising antibacterial activity against Psa and Xac. Their natural product origin and efficacy position them as potential lead compounds for managing plant bacterial canker diseases. © 2026 Society of Chemical Industry.