Transcription Factor AhR Regulates Glutathione S -Transferases Conferring Resistance to lambda -Cyhalothrin in Cydia pomonella .

Aryl hydrocarbon receptor (AhR) enhances insect resistance to insecticides by regulating the detoxification network. Our previous studies have confirmed that overexpressions of cytochrome P450 monooxygenases (P450s) and glutathione S -transferases (GSTs) are involved in lambda -cyhalothrin resistance in Cydia pomonella . Here, we report that CpAhR regulates the expression of GST and P450 genes, thus conferring resistance. Expression patterns indicated that the expression of CpAhR was highly induced by lambda -cyhalothrin exposure and upregulated in a lambda -cyhalothrin-resistant population. RNA interference (RNAi) of CpAhR decreases the expression of key resistance-related genes ( CpGSTe3 , CpCYP9A121 , and CpCYP9A122 ) and the activity of the GST enzyme, reducing the tolerance to lambda -cyhalothrin. Furthermore, β-naphthoflavone, a novel agonist of AhR, was first proven to be effective in increasing CpAhR expression and larval tolerance to lambda -cyhalothrin. These results demonstrate that CpAhR regulates the expression of key detoxifying genes and GST activity, resulting in the development of resistance to lambda -cyhalothrin in C. pomonella .