Novel Cinnamic Acid Derivatives Containing the 1,3,4-Oxadiazole Moiety: Design, Synthesis, Antibacterial Activities, and Mechanisms.

There is a lack of effective antibacterial agents against rice bacterial leaf streak and leaf blight. Cinnamic acid derivatives containing the 1,3,4-oxadiazole moiety were synthesized, and their antibacterial activities against pv. () and pv. () were evaluated. Based on the three-dimensional quantitative structure-activity relationship (3D-QSAR) model, compound with better antibacterial activity against was designed and synthesized, and the 50% effective concentration (EC) value was 0.2 mg/L. The curative and protective activities of compound against rice bacterial leaf streak at 100 mg/L were 39.5 and 35.4%, respectively, which were higher than those of thiodiazole copper (28.4 and 20.7%, respectively). The antibacterial activity of compound against rice bacterial leaf streak is closely associated with the activity of related defensive enzymes and the increase in glutathione metabolism.