Involvement of the cytochrome P450 genes CYP6DW3 and CYP4C64 in afidopyropen resistance in Bemisia tabaci Mediterranean (Q biotype)

The tobacco whitefly, Bemisia tabaci, is a notorious pest affecting various crops globally, and it exhibits high levels of resistance to various insecticides. Afidopyropen is a recently commercialized pyropene insecticide for B. tabaci control with high selectivity and a novel mode of action. We previously identified a high level of afidopyropen resistance in a field-collected population after selection in the lab, and named it the HD-Afi strain. In the present study, minimal cross-resistance in the HD-Afi strain was found between afidopyropen and other common chemical agents. However, the P450 enzyme activity in HD-Afi was 2.18 times the level in susceptible strain HD-S. Expression analysis revealed that two of 12 candidate P450 genes, namely CYP6DW3 and CYP4C64, were significantly up-regulated in HD-Afi. Silencing CYP6DW3 and CYP4C64 by RNA interference (RNAi) substantially increased the susceptibility of whitefly adults, confirming their involvement in afidopyropen resistance. Homology modeling and molecular docking analyses demonstrated stable binding of afidopyropen to CYP6DW3 and CYP4C64, with binding free energies of –6.87 and –6.11 kcal mol^–1, respectively. The findings of this study suggest that the induction of CYP6DW3 and CYP4C64 facilitates afidopyropen detoxification, contributing to the development of resistance in B. tabaci.