3.4. Mutant A. gossypii esterases exhibit low OP resistance
To determine whether mutant carboxylesterases were involved in insecticide resistance, we evaluated the resistance levels of transgenic flies to four organophosphorus and one pyrethroid insecticides, in which exogenous wild-type or mutant carboxylesterases were expressed by the tub-Gal4 promoter. CpEST-151D or CpEST-271L transgenic flies did not show higher resistance levels to the tested insecticides. Instead, these flies were more susceptible to parathion, malathion, or deltamethrin than the wild-type CpEST transgenic flies were (P ≤ 0.05) ( Table 1). The AgEST-151D mutant flies significantly exhibited 1.4-fold higher resistance to chlorfenvinphos (P