Transgenic expression of SeCYP9A186 and PxFMO2 confers resistance to emamectin benzoate in Plutella xylostella.

Background: The overexpression of metabolic enzymes constitutes a crucial mechanism for insects to detoxify xenobiotics and metabolic pesticides. A flavin-containing monooxygenase gene (PxFMO2) from Plutella xylostella and a P450 gene (SeCYP9A186, F116V mutant allele) from Spodoptera exigua have been reported to be involved in insecticide resistance. In this study, we aim to utilize transgenic technology to validate their in vivo detoxification functions in Plutella xylostella.

Results: We established two transgenic strains of Plutella xylostella with expressing an endogenous PxFMO2 gene from Plutella xylostella and an exogenous SeCYP9A186 gene from S. exigua, respectively. Bioassays demonstrated that the transgenic Plutella xylostella strain (IPP-FMO2) expressing PxFMO2 exhibited a 12-fold resistance to emamectin benzoate and a 6.4-fold resistance to chlorantraniliprole compared to the background strain (IPP-S). In contrast, the transgenic Plutella xylostella strain (IPP-9A186) expressing SeCYP9A186 displayed a 235-fold resistance to emamectin benzoate and a 115-fold resistance to abamectin. Moreover, resistance to emamectin benzoate in the IPP-9A186 strain of Plutella xylostella was inherited as an incompletely dominant trait and was genetically linked to the transgene locus.

Conclusions: Our results not only elucidated the in vivo contribution of the PxFMO2 and SeCYP9A186 to the insecticide resistance phenotype in Plutella xylostella, but also provided a genetic engineering toolkit to manipulate resistance pathways. These insights and methodologies could further aid in developing sustainable pest management strategies in Plutella xylostella. © 2024 Society of Chemical Industry.