Identification of cytochrome P450 genes that may contribute to imidacloprid and cyantraniliprole resistance in Bemisia tabaci (Hemiptera: Aleyrodidae) in Georgia, USA

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), commonly known as sweet potato whitefly, is a major insect pest for vegetable and agronomic crops in Georgia. Numerous laboratory and field studies have shown that whiteflies in Georgia are highly susceptible to developing resistance to the insecticides imidacloprid (neonic) and cyantraniliprole (diamide). However, the underlying mechanisms and resistance levels in Georgian populations are not yet fully understood. Previous Studies have revealed that increased levels of cytochrome P450 (CYP450) detoxifying enzyme in insect cells is involved with insecticide resistance. The MEAM1 B-biotype of whitefly, a prominent invasive species in Georgia is used in this study to examine potential resistance mechanisms regulated by CYP450 enzymes. The mRNA expression levels of CYP6CM1 and CYP6DW2 were upregulated for both imidacloprid and cyantraniliprole-resistant populations compared to a susceptible strain, among 8 CYP450 genes, based on quantitative real-time PCR (qPCR) analysis. In contrast, only the cyantraniliprole-resistant strain was found to have overexpressed CYP6CX2 and CYP6CX3. These findings suggest that multiple CYP450 genes are involved in insecticide resistance and could be targeted to reduce resistance in B. tabaci populations in Georgia using RNAi.