Functional expression of Helicoverpa armigera CYP9A12 and CYP9A14 in Saccharomyces cerevisiae

Elevated oxidative detoxification is a major mechanism responsible for pyrethroid resistance in Helicoverpa armigera from Asia. Constitutive overexpression of CYP9A12 and CYP9A14 was associated with pyrethroid resistance in the YGF strain of H. armigera. CYP9A12 and CYP9A14 were functionally expressed in the W(R) strain of yeast (Saccharomyces cerevisiae) transformed with a plasmid shuttle vector pYES2. The cell lysates prepared from yeast transformed with CYP9A12 and CYP9A14, respectively, exhibited considerable O-demethylation activities against two model substrates p-nitroanisole (0.59 and 0.42 nmol p-nitrophenol min−1 mg protein−1) and methoxyresorufin (2.98 and 5.41 pmol resorufin min−1 mg protein−1), and clearance activity against the pyrethroid esfenvalerate (8.18 and 4.29 pmol esfenvalerate min−1 mg protein−1). These results provide important evidence on the role of CYP9A12 and CYP9A14 in conferring pyrethroid resistance in H. armigera, and also demonstrate that the yeast expression system can provide necessary redox environment for insect P450s to metabolize xenobiotics.