Quercetin and paraoxon induction of hydrolase activity in<em> Helicoverpa armigera</em> and malathion-susceptible and resistant <em>Musca domestica</em>

Description

Organophosphate (OPs) insecticides are still widely used in pest control. The hydrolysis of OPs or oxons of organophosphorothionates by organophosphate hydrolases (OP-hydrolases) represents a major detoxification pathway of OPs. In this study, the response of insect OP-hydrolase activity to the allelochemical quercetin and the insecticide paraoxon, as well as changes in the activity of OP-hydrolases in malathion-resistance insects were characterized by using O, O-dimethyl-4-methylumbelliferyl phosphate (dMUP) and paraoxon as substrates. Hydrolase activity on dMUP was similar to hydrolase activity on paraoxon in Helicoverpa armigera and Musca domestica. Paraoxon-hydrolase activity was higher than dMUP-hydrolase activity in H. armigera fed on the artificial diet containing 0.2 % quercetin for 48 hours. In addition, similar induction of hydrolase activity on both paraoxon and dMUP was observed in H. armigera fed an artificial diet containing the LC10 or LC50 of paraoxon for 24 hours. In contrast, the hydrolysis activity onto dMUP was higher than the activity onto paraoxon in the malathion-resistant M. domestica. It was also found that the hydrolysis activity onto alpha-NA in malathion-resistant M. domestica was higher than that in malathion-susceptible M. domestica. These results provide a structural insight into the hydrolytic metabolism of organophosphates in insects.

Abstract

International audience

Additional details