Identification of the CYPome associated with acetamiprid resistance based on the chromosome-level genome of Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae)

Abstract

BACKGROUND: The bean flower thrips, Megalurothrips usitatus, poses a great threat to cowpea and other legume cultivars. Chemical insecticides have been applied to control M. usitatus, but have resulted in little profit because of the rapid evolution of insecticide resistance. To characterize the potential insecticide resistance mechanisms in M. usitatus, we sequenced and assembled a chromosome-level genome of M. usitatus by combining PacBio sequencing and Hi-C technology using a susceptible population. RESULTS: The genome size was 248.60 Mb and contained 14 128 protein-coding genes. The expansion genes of M. usitatus were enriched in the functional categories of heme binding and monooxygenase activity. We further identified 103 cytochrome P450 genes from the M. usitatus genome, 33 of which belonged to the CYP6 family. Ten CYP6 genes were significantly overexpressed in an acetamiprid-resistant population of M. usitatus. An RNA interference bioassay showed that knockdown of CYP6FW1, CYP6GM5, CYP6GM6, and CYP6GM7 significantly reduced acetamiprid resistance in the resistant population. In addition, the expression of all four genes could be induced by acetamiprid exposure. AlphaFold2-based homology modeling and molecular docking analysis showed that the proteins with relevance to acetamiprid resistance had relatively lower binding free energy with the acetamiprid molecule. CONCLUSION: This study provides a reference genome and gene resources for future studies on the evolution of M. usitatus and related pest species, and highlights the importance of cytochrome P450s in insecticide resistance in this pest insect. © 2025 Society of Chemical Industry.