RNA interference of cytochrome P450 CYP6F subfamily genes affects susceptibility to different insecticides in Locusta migratoria.

Abstract

Many insect cytochrome P450s (CYPs) play critical roles in detoxification of insecticides. The CYP6 family is unique to the class Insecta, and its biochemical function has essentially been associated with the metabolism of xenobiotics. In this study, we sequenced and characterised the full-length cDNAs of five CYP genes from Locusta migratoria, a highly destructive agricultural pest worldwide. The five genes were predominantly expressed in brain, guts, fat bodies or Malpighian tubules. CYP6FE1, CYP6FF1 and CYP6FG1 were expressed at higher levels in fourth-instar nymphs than in other developmental stages. CYPFD2 is specifically expressed in adults, whereas CYP6FD1, CYP6FD2 and CYP6FE1 showed significantly lower expression in eggs than in other developmental stages. Deltamethrin suppressed CYP6FD1 expression in third-instar nymphs and upregulated the expression level of CYP6FD2, CYP6FF1 and CYP6FG1 at the dose of LD10 . Efficient RNA interference-mediated gene silencing was established for four of the five CYP genes. Silencing of CYP6FF1 increased the nymphal mortality from 23 to 50% in response to deltamethrin. Silencing of CYP6FD2 and CYP6FE1 increased the nymphal mortality from 32 to 72 and 66%, respectively, to carbaryl. Three of the four CYP6F subfamily genes in L. migratoria were associated with the detoxification of deltamethrin or carbaryl. The role of CYPs in insecticide detoxification appears to be both gene and insecticide specific. © 2016 Society of Chemical Industry.