Design and Synthesis of Novel Chroman-4-one Derivatives Containing a Sulfone Moiety as Potential Antibacterial Agents for Kiwifruit Bacterial Canker.

Kiwifruit bacterial canker caused by Pseudomonas syringaepv actinidiae (Psa) severely threatens kiwifruit production. In this study, a series of chroman-4-one derivatives containing a sulfone moiety were designed, synthesized, and evaluated as potential antibacterial agents against Psa. Most compounds exhibited inhibitory activity, and compound 3a showed the best effect with an EC50 value of 9.11 μg/mL, comparable to gentamicin sulfate. Microscopic analysis revealed that 3a could cause bacterial surface deformation and reduced flagella formation. In vivo assays showed that compound 3a exhibited protective and therapeutic efficacy against kiwifruit bacterial canker and enhanced plant resistance by inducing AcPR1 overexpression. These findings suggest that compound 3a represents a promising candidate for controlling kiwifruit bacterial canker.