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.

Novel Inhibitor of Glutamate-Cysteine Ligase Catalytic Subunit against Tribolium castaneum: High-Throughout Virtual Screening, Molecular Docking and Dynamics Simulation, and Bioassay

“…As shown in Figure , the larval mortality in the ZINC000032992384-treated group was 63.8% at 100 μM, which was significantly higher than that of the positive control, dichlorvos-treated group (29.1%) ( p < 0.01). Moreover, most of the larvae in the acetone-treated group (93.6%) were developed normally (Figure B), while those in the ZINC000032992384 and dichlorvos-treated groups were less developed and died (Figure C), which is similar to our previous findings that TcGclc knock-down caused metamorphosis deficiency .…”

“…Moreover, most of the larvae in the acetone-treated group (93.6%) were developed normally (Figure B), while those in the ZINC000032992384 and dichlorvos-treated groups were less developed and died (Figure C), which is similar to our previous findings that TcGclc knock-down caused metamorphosis deficiency . The result showed that ZINC000032992384 caused a deficiency in metamorphosis and antioxidant activity by inhibition of TcGclc activity and showed insecticide activity.…”

“…Our previous study showed that RNAi in TcGclc caused a larval metacarphosis defect by down-regulation of genes in the 20E signaling pathway. 21 Since ZINC000032992384 selected from the virtual screening showed the significant inhibition of TcGclc activity, we assessed the LC 50 of ZINC000032992384 to determine whether it has insecticidal activity against T. castaneum larvae. The result showed that the larval mortality increased with the increase of ZINC000032992384 concentration, and LC 50 was 34.79 mg/L (Figure 8A).…”

“…Moreover, most of the larvae in the acetone-treated group (93.6%) were developed normally (Figure 8B), while those in the ZINC000032992384 and dichlorvos-treated groups were less developed and died (Figure 8C), which is similar to our previous findings that TcGclc knock-down caused metamorphosis deficiency. 21 TcGclc plays an important role in metamorphosis through the 20E signaling pathway and antioxidant processes, and the knock-down of this gene causes metamorphosis deficiency and a decrease in antioxidant e n z y m e a c t i v i t y . 2 1 T h e r e s u l t s h o w e d t h a t ZINC000032992384 caused a deficiency in metamorphosis and antioxidant activity by inhibition of TcGclc activity and showed insecticide activity.…”

“…19 The gene sequence of TcGclc has been reported in T. castaneum. 20 Our previous study revealed that TcGclc not only has a response function to oxidants and insecticides but also is involved in metamorphosis, 21 suggesting the potential of TcGclc as a target for insecticides and insecticide resistance Since L-buthionine-(S,R)-sulfoximine (BSO), which is wellknown as a specific Gclc inhibitor, caused the host toxicity, studies to develop nontoxic inhibitors have been reported, 22 however, which is considered inappropriate to use insecticides because of their species-specific inhibition. Therefore, in order to develop potent insecticides that lower resistance risk, it is necessary to develop special inhibitors of insect Gclc.…”