A thioredoxin peroxidase protects Pieris rapae from oxidative stress induced by chlorantraniliprole exposure
Chlorantraniliprole (CAP) is an insecticide widely used to control the small white butterfly (SWB), Pieris rapae . Exposure to CAP can cause oxidative injury in SWB; however, it is unclear if antioxidant enzymes are involved in the defense process. In this study, a thioredoxin peroxidase ( PrTPX1 ) gene was identified from SWB by using a homology search method. The gene encoded a 195 amino-acid PrTPX1 protein. Sequence characteristics and phylogenetic analysis indicated that PrTPX1 was a typical “2-Cys” TPX, and the PrTPX1 gene consisted of four exons and three introns. Reverse transcription-quantitative polymerase chain reaction analysis indicated that the messenger RNA levels of PrTPX1 were highest in third-, fourth- and fifth-instar larval stages and in the larval midgut. Treatment with sublethal doses (LD 20 and LD 50 ) of CAP for 6, 12, 18, and 24 h resulted in increased H 2 O 2 concentration in SWB larvae, indicating insecticide-induced oxidative stress. The transcriptional levels of PrTPX1 were significantly enhanced in larvae exposed to CAP. Recombinant PrTPX1 protein was expressed in Escherichia coli . Enzymatic assay revealed that the protein displayed antioxidant activity and was able to protect against oxidative challenge. These results indicated that PrTPX1 plays an important role in oxidative stress responses and may contribute to the CAP tolerance in SWB. Highlights PrTPX1 transcription was upregulated by chlorantraniliprole. Recombinant PrTPX1 protein displayed antioxidant activity. PrTPX1 prevented oxidative stress and enhanced tolerance to chlorantraniliprole.
危险品化学品经营许可证（带存储）