Functional validation of key cytochrome P450 monooxygenase and UDP-glycosyltransferase genes conferring cyantraniliprole resistance in Aphis gossypii Glover

Cytochrome P450 monooxygenases (P450s) and UDP-glycosyltransferases (UGTs) are major detoxifying enzymes that metabolize plant toxins and insecticides. In the present study, the synergists of piperonyl butoxide, sulfinpyrazone and 5-nitrouracil significantly increased cyantraniliprole and alpha-cypermethrin toxicity against the resistant strain. The transcripts of UGT341A4, UGT344B4, UGT344D6, UGT344J2 and UGT344M2 increased significantly in the CyR strain compared with the susceptible strain. Among these upregulated genes (including P450s), CYP6CY7 and UGT344B4 were highly expressed in the midgut. Transgenic expression of the P450 and UGT genes in broad body tissues in Drosophila melanogaster indicated that the expression of CYP380C6, CYP4CJ1, UGT341A4, UGT344B4 and UGT344M2 is sufficient to confer cyantraniliprole resistance, and CYP380C6, CYP6CY7, CYP6CY21, UGT341A4 and UGT344M2 are related to alpha-cypermethrin cross-resistance. The midgutspecific overexpression of CYP380C6, CYP6CY7, CYP6CY21, CYP4CJ1, UGT341A4, UGT344B4 and UGT344M2 significantly increased insensitivity to cyantraniliprole, and CYP380C6, CYP6CY7, CYP6CY21, UGT344B4 and UGT344M2 confer alpha-cypermethrin cross-resistance. The expression of CYP380C6, CYP4CJ1, UGT341A4 and UGT344M2 in broad tissues or in midgut has similar effects on insensitivity to insecticides; however, CYP6CY7, CYP6CY21 and UGT344B4 are more effective in the midgut. This result indicates that broad body tissues and midgut tissue are involved in insecticide resistance mediated by the candidate P450s and UGTs examined.

Automated summary

The study identified synergists that enhance the toxicity of certain insecticides, observed upregulation of UGT genes in resistant strains, and demonstrated the role of specific P450 and UGT genes in conferring resistance to certain insecticides. Transgenic expression in Drosophila melanogaster confirmed the involvement of certain genes in mediating insecticide resistance.