谷胱甘肽S-转移酶CsGSTσ1在桃小食心虫对高效氯氟氰菊酯解毒代谢中的作用研究OA

[Aim]This study aims to explore the role of glutathione S-transferase(GST),which is upregulated in Carposina sasakii induced by lambda-cyhalothrin,in the detoxification metabolism of this insecticide,so as to lay the groundwork for further research on the role of GST in the metabolic resistance of C.sasakii.[Methods]Using the BLAST method,the coding sequences(CDSs)of GST genes in C.sasakii were identified based on the genome and transcriptome data.A phylogenetic tree of 14 GST proteins from C.sasakii and GST proteins from other insects was constructed using the neighbor-joining method.The median lethal concentration(LC50)value of lambda-cyhalothrin against the 3rd instar larvae of C.sasakii in 48 h was determined with drop method.At 48 h after exposure of the 3rd instar larvae of C.sasakii to LC50 of lambda-cyhalothrin,the GST activity in larvae was measured using a microplate reader with 1-chloro-2,4-dinitrobenzene(CDNB)and reduced glutathione(GSH)as substrates,and the expression levels of GST genes(CsGSTσ1,CsGSTσ2,CsGSTσ3,CsGSTσ4,CsGSTδ1,CsGSTδ4,CsGSTδ6,CsGSTω1,CsGSTω2,CsGSTω3,CsGSTω4,CsGSTε1,CsGSTζ2 and CsGSTζ3)were detected using RT-qPCR.The prokaryotic expression of CsGSTσ1,which was significantly induced and showed the highest expression level,was performed in vitro,and the enzyme kinetics of CsGSTσ1 was analyzed using a microplate reader.The metabolic activity of the recombinant CsGSTσ1 against lambda-cyhalothrin was analyzed by using ultra-high-performance liquid chromatography(UHPLC),and the antioxidant activity of CsGSTσ1 was measured using the disc diffusion assay.[Results]The phylogenetic tree showed that the 14 GSTs of C.sasakii belonged to the Delta,Sigma,Omega,Zeta and Epsilon families.The LC50 value of lambda-cyhalothrin against the 3rd instar larvae of C.sasakii in 48 h was 2.646 mg/L.At 48 h after induction with LC50 of lambda-cyhalothrin,the GST activity in the 3rd instar larvae of C.sasakii significantly increased and the expression level of CsGSTσ1 was significantly upregulated by 15.33-fold as compared to those of the control.The recombinant CsGSTσ1 had the Km value of(151.60±24.03)μmol/L and the Vmax value of(445.6±21.1)μmol/(min·mg),indicating good catalytic activity.The recombinant CsGSTσ1 exhibited metabolic activity against lambda-cyhalothrin.The disk diffusion assay results showed that CsGSTσ1 played a role in defending against oxidative stress damage.[Conclusion]CsGSTσ1 may be involved in the metabolism of lambda-cyhalothrin in C.sasakii.