Overexpression of CYP6CY36 and CYP380C34 contributes to metabolic resistance of Myzus persicae (Sulzer) to flupyradifurone

Flupyradifurone is a novel butenolide insecticide widely applied to control a broad range of sucking pests, including Myzus persicae. However, resistance monitoring has revealed that several Chinese populations have developed moderate resistance to flupyradifurone. Therefore, we investigated the risk and underlying mechanisms of flupyradifurone resistance in M. persicae. A flupyradifurone-resistant strain (FDF-R) was established through 14 generations of selection and exhibited a 35.02-fold increase in resistance. FDF-R showed cross-resistance to acetamiprid (13.9-fold), sulfoxaflor (3.5-fold), and imidacloprid (4.2-fold), but not to tested pyrethroid or carbamate insecticides. The synergist piperonyl butoxide significantly increased flupyradifurone toxicity in FDF-R, suggesting the involvement of cytochrome P450 monooxygenases, whereas the other two synergists had no effect. Enzyme assays revealed 1.74-fold higher P450 activity in FDF-R compared to the susceptible strain. Gene expression analysis showed significant overexpression of seven P450 genes, including CYP380C34, CYP6CY36, CYP6CY4, and CYP6CY3. Moreover, RNAi silencing of CYP6CY36 and CYP380C34 significantly increased susceptibility to flupyradifurone. Additionally, molecular docking further confirmed strong binding affinities between these two P450 enzymes and flupyradifurone. These findings demonstrate that P450-mediated detoxification contributes to M. persicae resistance to flupyradifurone.