Innovative Strategy for the Control of Citrus Canker: Inhibitors Targeting the Type III Secretion System of Subsp. .

To find potential type III secretion system (T3SS) inhibitors against citrus canker caused by subsp. (), a new series of 5-phenyl-2-furan carboxylic acid derivatives stitched with 2-mercapto-1,3,4-thiadiazole were designed and synthesized. Among the 30 compounds synthesized, 14 compounds significantly inhibited the promoter activity of a harpin gene Eight of the 14 compounds did not affect the growth of , but significantly reduced the hypersensitive response (HR) of tobacco and decreased the pathogenicity of on citrus plants. Subsequent studies have demonstrated that these inhibitory molecules effectively suppress the T3SS of and significantly impair the pathogen's ability to subvert citrus immunity, resulting in a reduction in the level of disease progression. As a result, our work has identified a series of potentially attractive agents for the control of citrus canker.