The glutathione biosynthesis is involved in metamorphosis, antioxidant function, and insecticide resistance in Tribolium castaneum

Abstract

BACKGROUNDReduced glutathione (GSH) synthesis is vital for redox homeostasis, cell‐cycle regulation and apoptosis, and immune function. The glutamate–cysteine ligase catalytic subunit (Gclc) is the first and rate‐limiting enzyme in GSH synthesis, suggesting the potential use of Gclc as a pesticide target. However, the functional characterization of Gclc, especially its contribution in metamorphosis, antioxidant status and insecticide resistance, is unclear in Tribolium castaneum.RESULTSIn this study, we identified and cloned Gclc from T. castaneum (TcGclc) and found that its expression began to increase significantly from the late larvae (LL) stage (3.491 ± 0.490‐fold). Furthermore, RNA interference‐mediated knockdown of TcGclc resulted in three types of aberration (100% total aberration rate) caused by the downregulation of genes related to the 20‐hydroxyecdysone (20E) pathway. This deficiency was partially rescued by exogenous 20E treatment (53.1% ± 3.2%), but not by antioxidant. Moreover, in the TcGclc knockdown group, GSH content was decreased to 62.3%, and total antioxidant capacity, glutathione peroxidase and total superoxide dismutase activities were reduced by 14.6%, 83.6%, and 82.3%, respectively. In addition, treatment with different insecticides upregulated expression of TcGclc significantly compared with a control group during the late larval stage (P < 0.01).CONCLUSIONOur results indicate that TcGclc has an extensive role in metamorphosis, antioxidant function and insecticide resistance in T. castaneum, thereby expanding our understanding of GSH functions and providing a scientific basis for pest control. © 2024 Society of Chemical Industry.