Effects of different concentrations of thiamethoxam on the activity of protective and detoxification enzymes in Riptortus pedestris.

WANG Zi-Jie; YANG Fang-Zhe; LIU Tian-Jie; TIAN Xin-Yue; WANG Yue-Ying; SHI Shu-Sen; GAO Yu

[Aim] To measure changes in the activity of protective and detoxifying enzymes in the F0 and the F1 generations of the 3rd instar of Riptortus pedestris nymphs exposed to different concentrations of thiamethoxam. [Methods] Reniform soybean seeds soaked in water were immersed in 25% thiamethoxam WG that had been diluted with different amounts of water to obtain LC10 (5.2 mg/L), LC20 (11.2 mg/L), LC30 (19.6 mg/L), LC40 (31.6 mg/L) and LC50 (49.4 mg/L) solutions. Water was the control. F0 nymphs of R. pedestris were fed the treated seeds for 24 hours after which changes in the activity of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), acetylcholinesterase (AChE), glutathione S-transferase (GST) and carboxylesterase (CarE) in surviving nymphs was measured. Another group of nymphs was placed in cages and fed soybean seeds treated with water until F1 generation nymphs had developed to the 3rd instar, after which changes in the activity of POD, CAT, SOD, AChE, GST, and CarE were determined in vivo. [Results] After treatment with different concentrations of thiamethoxam, the POD, CAT, SOD, GST and CarE activity of F0 generation nymphs was higher than that of the control group. POD, AChE, GST and CarE activity of F1 larvae were also higher than that of the control group. The POD, GST and CarE activity of F1 larvae was higher than those of F0 larvae for all treatment concentrations. AChE enzyme activity of F1 larvae was higher than that of F0 larvae for concentrations in the range of LC20-LC50. Protective and detoxifying enzyme activity in F0 and F1 larvae was positively correlated with thiamethoxam concentration. [Conclusion] F0 R. pedestris nymphs detoxify thiamethoxam by increasing their POD, CAT, SOD, GST and CarE enzyme activity, whereas F1 nymphs detoxify thiamethoxam by increasing their POD, AChE, GST and CarE activity. The observed changes in POD, AChE, GST and CarE enzyme activity may be the mechanism responsible for pesticide resistance in R. pedestris F1 nymphs.

PESTICIDE resistance; SUPEROXIDE dismutase; DRUG resistance; ACETYLCHOLINESTERASE; ENZYMES; THIAMETHOXAM

Chinese Journal of Applied Entomology, 2024, Vol 61, Issue 5, p1037

2095-1353

Academic Journal

10.7679/j.issn.2095-1353.2024.105