Diphenyl Ether Hydrazone Derivatives as Novel Succinate Dehydrogenase Inhibitors for Effective Control of Rice Sheath Blight.

Rice sheath blight, caused by pathogen, poses a significant threat to global food security. To address this challenge, we designed and synthesized diphenyl ether hydrazone derivatives () as potential succinate dehydrogenase inhibitors. Most of these derivatives achieved 100% inhibition against at 50 μg/mL concentration. Notably, compound exhibited an exceptional efficacy of 95% control rate with an EC of 0.28 μg/mL, which significantly outperformed boscalid at a concentration of 200 μg/mL, without affecting the rice growth and development. Furthermore, after treatment with , the growth morphology and intracellular changes of mycelia were consistent with those observed with boscalid. Additionally, the IC values of compounds and were 1.55 and 1.11 μM, respectively, which were better than the IC value of boscalid (1.85 μM). The finding by molecular docking studies revealed that compound interacts with novel binding sites, offering an opportunity for the development of innovative SDH inhibitors for the efficient control of rice sheath blight disease.