Glutathione S-transferase contributes to the resistance of Megalurothrips usitatus against lambda-cyhalothrin by strengthening its antioxidant defense mechanisms

The damage caused by Megalurothrips usitatus, a common pest, has significantly affected the Chinese vegetable industry The inappropriate application of chemical pesticides has led to the development of high resistance in the M. usitatus to conventional insecticides. Glutathione S-transferase (GSTs), known for its multifunctional properties, contributes to detoxification and antioxidation. It enhances the insects’ adaptability to pesticides by facilitating the elimination of lipid peroxidation (LPO) products resulting from pyrethroid insecticides. The research employed RT-qPCR to identify GSTs genes that exhibited significant expression in response to lambda-cyhalothrin stress. It also quantified changes in antioxidant and apoptosis markers within the M. usitatus under lambda-cyhalothrin exposure. The functional significance of GSTs was validated by assessing alterations in the antioxidant defense system and resistance to lambda-cyhalothrin following the inhibition of GSTs activity. The study’s outcomes indicated that MuGSTS1 was markedly upregulated in response to lambda-cyhalothrin stress (P<0.0001). The GSTs activity was effectively suppressed by the specific inhibitor, diethyl maleate (DEM), achieving an inhibition rate of 64.05%. Following the inhibition of GSTs, the overall antioxidant capacity was reduced by 3.1-fold compared to the control, and the M. usitatus exhibited a 7.91-fold increase in sensitivity to lambda-cyhalothrin. These findings confirm the pivotal role of GSTs in the oxidative stress response of the M. usitatus and their contribution to the development of resistance to lambda-cyhalothrin through enhanced antioxidant defenses, providing valuable insights into insects’ adaptive responses to chemical stressors.