3(2: H)-pyridazinone derivatives: A new scaffold for novel plant activators

Due to the emergence of drug resistance, pesticide residue and environmental contamination, it is important to develop novel eco-friendly strategies to protect plants. Among them, plant activators have been gaining more and more attention. Herein, based on SHAFTS method, a new scaffold for novel plant activators was predicted and the discovery and structure-Activity relationships of a series of 3(2H)-pyridazinone derivatives as novel plant activators were elucidated in detail. The vast majority of compounds exhibited excellent broad-spectrum induced resistance activity against tested diseases in vivo but no direct antimicrobial activity in vitro. Among them, compound 32 showed excellent efficacy against four pathogens and great potential as new plant activators in crop protection.