Abstract
The control of P. xylostella primarily involves chemical insecticides, but overuse has brought about many negative effects. Our previous study reported that (S)-(-)-palasonin (PLN) is a plant-derived active substance with significant insecticidal activity against P. xylostella. However, we noticed a possible cross-resistance between (S)-(-)-palasonin and other insecticides which may be related to metabolic detoxification. In order to further explore the detoxification effect of detoxification enzymes on (S)-(-)-palasonin in P. xylostella, the effects of (S)-(-)-palasonin on enzyme activity and transcription level were determined, and the detoxification and metabolism of GSTs on (S)-(-)-palasonin were studied by in vitro inhibition and metabolism experiments. During this study, GST enzyme activity was significantly increased in P. xylostella after (S)-(-)-palasonin treatment. The expression levels of 19 GSTs genes were significantly increased whereas the expression levels of 1 gene decreased. Furthermore, (S)-(-)-palasonin is shown to be stabilized with GSTs and metabolized GSTs (GSTd1, GSTd2, GSTs1 and GSTs2) in vitro, with the highest metabolic rate of 80.59% for GSTs1. This study advances the beneficial utilization of (S)-(-)-palasonin as a botanical pesticide to control P. xylostella in the field.