Overexpression of Contributing to Detoxification of Multiple Insecticides in (L.).

The diamondback moth, (L.), has evolved with varying degrees of resistance to almost all major classes of insecticides and has become the most resistant pest worldwide. The multiresistance to different types of insecticides has been frequently reported in , but little is known about the mechanism. In this study, a carboxylesterase (CarE) gene, , was found significantly overexpressed in a field-evolved multiresistant population and can be dramatically induced by eight of nine tested insecticides. Results of the real-time quantitative polymerase chain reaction (RT-qPCR) showed that was predominantly expressed in the midgut and malpighian tubule of larvae. Knockdown of dramatically increased the susceptibility of the larvae to β-cypermethrin, bifenthrin, chlorpyrifos, fenvalerate, malathion, and phoxim, while overexpression of in increased the tolerance of the fruit flies to these insecticides obviously. More importantly, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay showed that the recombinant PxαE14 expressed in exhibited metabolic activity against the six insecticides. The homology modeling, molecular docking, and molecular dynamics simulation analyses showed that these six insecticides could stably bind to PxαE14. Taken together, these results demonstrate that constitutive and inductive overexpression of contributes to detoxification of multiple insecticides involved in multiresistance in . Our findings provide evidence for understanding the molecular mechanisms underlying the multiresistance in insect pests.