Functional Characterization of Two Carboxylesterase Genes Involved in Pyrethroid Detoxification in .

Insect carboxylesterases are major enzymes involved in metabolism of xenobiotics including insecticides. Two carboxylesterase genes, and , were cloned from the destructive agricultural pest . Quantitative real-time polymerase chain reaction showed that and were predominantly expressed in fat body and midgut, respectively; developmental expression analyses found that the expression levels of both CarEs were significantly higher in fifth-instar larvae than in other life stages. Recombinant CarE001A and CarE001H expressed in the exhibited high enzymatic activity toward α-naphthyl acetate. Inhibition assays showed that organophosphates had strong inhibition on CarEs activity compared to pyrethroids. Metabolism assays indicated that CarE001A and CarE001H were able to metabolize β-cypermethrin and λcyhalothrin. Homology modeling and molecular docking analyses demonstrated that β-cypermethrin could fit nicely into the active pocket of both carboxylesterases. These results suggested that and could play important roles in the detoxification of pyrehtroids in .