Induction effect of acetamiprid stress on the activities of protective enzymes and detoxification enzymes in Tuta absoluta

Objective To explore the temporal dynamic response patterns of protective enzymes (SOD, POD, CAT) and detoxification enzymes (CarE, GST, MFO) in Tuta absoluta under sublethal concentrations (LC₁₀, LC₂₅) of acetamiprid, and clarify the physiological induction characteristics of the pest under sublethal acetamiprid stress.

Methods The leaf-dipping bioassay was adopted to determine the sublethal concentrations of acetamiprid against the 2nd-instar larvae of Tuta absoluta. Larva samples were collected at 1, 6, 12, 24, 48 and 72 h after chemical treatment, and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), carboxylesterase (CarE), glutathione S-transferase (GST) and mixed-function oxidase (MFO) were measured and compared.

Results Low-concentration acetamiprid inhibited POD activity in the early treatment stage; CAT activity increased gradually with the extension of stress time. The change trend of SOD activity under low acetamiprid concentration presented "inhibition-induction-inhibition", while it showed "induction-inhibition-induction" under high concentration. Acetamiprid generally inhibited CarE activity but induced MFO activity. GST activity was first suppressed then induced under low concentration, while no obvious fluctuation was observed under high concentration.

Conclusion Sublethal acetamiprid can significantly alter the activity of protective and detoxification enzymes in Tuta absoluta within a certain period of time.