Discovery of Natural Rosin Derivatives Containing Oxime Ester Moieties as Potential Antifungal Agents to Control Tomato Gray Mold Caused by .

Inspired by the application of natural products against pathogenic fungi, two series of dehydroabietyl oxime ester derivatives were synthesized using rosin as a raw material. Based on the evaluation and screening of antifungal activities against (), , , , , and , compound exhibited the best antifungal activity against , and its EC was 0.798 mg/L, which was lower than that of the positive control trifloxystrobin (1.112 mg/L). The antifungal activity results showed that had satisfactory protective and curative effects on tomato. Physiological and biochemical studies showed that the action mechanism of compound against is to change the morphology and the ultrastructure of the mycelium, increase the permeability of the cell membrane, and cause nucleus and mitochondrial dysfunction, thus leading to apoptosis. In addition, qualitative and quantitative structure-activity relationship studies showed that the inductive and conjugative interactions between compound and the target receptor form an electron transfer process, thereby achieving an antifungal effect. These results indicated that compound , which was derived from the natural product rosin, is a novel potential fungicidal candidate against .