Functional Analysis of SlGSTE12 in Pyrethroid and Organophosphate Resistance in Spodoptera litura

Abstract

Glutathione S-transferase genes in the epsilon group were reported to function in insecticide resistance. SlGSTE12 was validated to be overexpressed in pyrethroid-and organophosphate-resistant populations of Spodoptera litura compared to a susceptible population. A functional study of heterologously expressed SlGSTE12 showed that K m and V max for 1-chloro-2,4dinitrobenzene (CDNB) conjugating activity were 0.70 ± 0.18 mmol L −1 and 90.6 ± 9.4 nmol mg −1 min −1 , respectively. β-Cypermethrin and cyhalothrin showed much weaker inhibition of SlGSTE12 activity to CDNB conjugation than fenvalerate, chlorpyrifos, and phoxim. Ultrahigh-performance liquid chromatography analysis showed that SlGSTE12 had significant metabolism activity to fenvalerate and phoxim both in vitro and in Escherichia coli, especially to chlorpyrifos, and slight metabolism activity toward cyhalothrin only in vitro. Silencing of SlGSTE12 by RNAi increased the mortality to fenvalerate, cyhalothrin, and chlorpyrifos significantly. SlGSTE12 also had a significant antioxidant ability against cumene hydroperoxide. Our study suggested that SlGSTE12 could metabolize phoxim, fenvalerate, cyhalothrin, and especially chlorpyrifos. SlGSTE12 might also participate in pyrethroid and organophosphate resistance by antioxidant activity.

CRISPR/Cas9-Mediated Knockout Reveals the Involvement of CYP304F1 in β-Cypermethrin and Chlorpyrifos Resistance in Spodoptera litura

“…The resistance for these insecticides might involve the other detoxification genes, such as the involvement of SlGSTE12 in fenvalerate and phoxim resistance. 31 In summary, the overexpression of CYP304F1 in the QJ population and the increased susceptibility of larvae to βcypermethrin and chlorpyrifos in the QJ-CYP304F1 population confirmed the involvement of CYP304F1 from the CYP2 clan in the insecticide resistance of S. litura. Considering the relatively low RR values and overlapping of LD 50 values (95% FL) in QJ and QJ-CYP304F1 populations, CYP304F1 might contribute to β-cypermethrin and chlorpyrifos resistance in a limited manner.…”

“…In addition, the QJ population showed a high resistance level to fenvalerate, β-cypermethrin, cyhalothrin, chlorpyrifos, and phoxim when compared with the GX population. 31 RNA Extraction, Library Preparation, and Sequencing. The third instar larvae of S. litura in GX and QJ populations were sampled for RNA extraction using the TaKaRa MiniBEST Universal RNA Extraction Kit (Takara, Dalian, China).…”

“…QJ and GX populations of S. litura were used in this study, and their information was provided by Li et al . , Briefly, the QJ population was derived from a field population collected from Qianjiang, Hubei province (China), in 2019. The GX population was kindly provided by Guangxi Tianyuan Biochemistry Corp., Ltd., and served as a susceptible population.…”

Toxicity of Ribavirin to Spodoptera litura by Inhibiting the Juvenile Hormone

“…Insects. S. litura populations of GX and QJ were used in this study, and their information was described by Li et al 14 Briefly, the GX population of S. litura, susceptible to chemical insecticides, was first collected from Guangxi province (China) and kept in a laboratory for more than 10 years. The QJ population of S. litura showing a high resistance level to pyrethroids and organophosphates was collected from the cotton field at the larvae stage from Hubei province (China) in the August of 2019.…”

“…S. litura populations of GX and QJ were used in this study, and their information was described by Li et al Briefly, the GX population of S. litura, susceptible to chemical insecticides, was first collected from Guangxi province (China) and kept in a laboratory for more than 10 years.…”