Cloning and expression profiles of cytochrome P450 CYP6DV5 in Bemisia tabaci and its role in resistance of B. tabaci to thiamethoxam

Bemisia tabaci seriously damages the normal growth of agriculture crops. Thiamethoxam is a secondary product of neonicotinoid insecticide that is widely used in the control of B. tabaci. However, due to the increasing usage of thiamethoxam, B. tabaci has developed severe resistance to thiamethoxam in the fields. The mechanism of B. tabaci resistance to thiamethoxam is still unknown. In this study, we found that cytochrome P450 CYP6DV5 gene was overexpressed (2.95-fold) in a thiamethoxam resistant strain by comparing with the susceptible strain (Q-biotype). The full-length sequence of the gene was cloned according to the genome database. Sequence analysis results showed that the gene had conserved domains of cytochrome P450 gene, which was a typical insect P450 gene. Further analysis of the expression of CYP6DV5 in different developmental stages and body parts showed that CYP6DV5 gene was abundant in the adult stage and head of B. tabaci. We also found that thiamethoxam could significantly induce the expression of this gene. Finally, the knockdown of CYP6DV5 gene could significantly increase the sensitivity of B. tabaci to thiamethoxam. Results demonstrated that CYP6DV5 was involved in thiamethoxam resistance in B. tabaci. The results will contribute to reveal the mechanism of resistance formation of B. tabaci to thiamethoxam, and will provide a theoretical basis for the management of B. tabaci.