Key Contributions of the Overexpressed Plutella xylostella Sigma Glutathione S -Transferase 1 Gene ( PxGSTs1 ) in the Resistance Evolution to Multiple Insecticides.

The overexpression of insect detoxification enzymes is a typical adaptive evolutionary strategy for insects to cope with insecticide pressure. In this study, we identified a glutathione S -transferase (GST) gene, PxGSTs1 , that exhibited pronounced expression in the field-resistant population of Plutella xylostella . By using RNAi (RNA interference), the transgenic fly models, and quantitative real-time polymerase chain reaction (RT-qPCR) methods, we confirmed that the augmented expression of PxGSTs1 mediates the resistance of P. xylostella to various types of insecticides, including chlorantraniliprole, novaluron, λ-cyhalothrin, and abamectin. PxGSTs1 was found to bolster insecticide resistance in two ways: direct detoxification and enhancing antioxidative defenses. In addition, our findings demonstrated that pxy-miR-8528a exerts a pivotal influence on forming insecticide resistance in P. xylostella by downregulating PxGSTs1 expression. In summary, we elucidated the multifaceted molecular and biochemical underpinnings of PxGSTs1 -driven insecticide resistance in P. xylostella . Our results provide a new perspective for understanding the insecticide resistance mechanism of P. xylostella .