Unraveling Key\nAmino Acid Residues Crucial for PxGSTs1\nConferring Benzoylurea Insecticide Resistance in Plutella\nxylostella

The widespread use of benzoylurea insecticides (BUs)\nhas led to\nsignificant resistance issues in various agricultural pests. Previous\nstudies have demonstrated that the overexpression of sigma glutathione\nS-transferase 1 (PxGSTs1) can confer resistance to novaluron in Plutella xylostella; however, the underlying molecular\nmechanism remains unclear. This study investigates the role of glutathione\nS-transferase PxGSTs1 in mediating resistance to BUs in P. xylostella. Using a combination of RNA interference\nand transgenic Drosophila models, we\ndemonstrated that the overexpression of <i>PxGSTs1</i> significantly\ncontributes to the resistance against BUs. Functional assays revealed\nthat PxGSTs1 binds to these insecticides with varying affinities.\nStructural analysis through homology modeling and molecular docking\nidentified the importance of hydrogen bonding and pi–pi stacking\nin resistance mechanisms. Site-directed mutagenesis confirmed the\ncritical role of Ser65 and Tyr97 in these interactions. Our findings\nprovide a molecular basis for the development of novel BUs and inform\nstrategies for managing BU resistance in P. xylostella.