Flavin-Dependent\nMonooxgenase Confers Resistance to\nChlorantraniliprole and Spinetoram in the Rice Stem Borer Chilo suppressalis Walker (Lepidoptera: Crambidae)

Understanding the role of flavin-containing monooxygenases\n(FMOs)\nin the genetic mechanisms of insecticide resistance is essential for\ndeveloping effective management strategies against the rice stem borer, Chilo suppressalis. In this study, we identified\nfive FMO genes in C. suppressalis,\nexamined their expression patterns, and revealed overexpression of <i>FMO3B</i> and <i>FMO3C</i> in field populations resistant\nto multiple insecticides, including chlorantraniliprole and spinetoram.\nFunctional characterization using transgenic <i>Drosophila</i> indicated that FMO3B and FMO3C do not confer resistance to abamectin\nor methoxyfenozide but do mediate resistance to chlorantraniliprole\nand spinetoram. Knockdown of <i>FMO3B</i> and <i>FMO3C</i> increased sensitivity to these insecticides in C.\nsuppressalis. Molecular docking studies indicated\ndirect binding of chlorantraniliprole and spinetoram to these FMOs,\nunderscoring their role in metabolic resistance. These findings indicate\nthat FMOs are key enzymes in the metabolic resistance of C. suppressalis to chlorantraniliprole and spinetoram,\nenhancing our understanding of insecticide resistance and aiding the\ndevelopment of management strategies.