Inducible Gut-Specific Carboxylesterase SlCOE030 in Polyphagous Pests of Spodoptera litura Conferring Tolerance between Nicotine and Cyantraniliprole

Abstract

Insecticides tolerance in herbivorous arthropods is associated with preadaptation to host plant allelochemicals. However, how plant secondary metabolites activate detoxifying metabolic genes to develop tolerance remains unclear. Herein, the tolerance of Spodoptera litura larvae to cyantraniliprole was increased after nicotine exposure. An S. litura α esterase, SlCOE030, was predominantly expressed in the midgut and induced after exposure to cyantraniliprole, nicotine, and cyantraniliprole plus nicotine. Drosophila melanogaster with ectopically overexpressed SlCOE030 enhanced cyantraniliprole and nicotine tolerance by 4.91- and 2.12-fold, respectively. Compared to UAS-SlCOE030 and Esg-GAL4 lines, the Esg > SlCOE030 line laid more eggs after nicotine exposure. SlCOE030 knockdown decreased the sensitivity of nicotine-treated S. litura larvae to cyantraniliprole. Metabolism assays indicated that recombinant SlCOE030 protein metabolizes cyantraniliprole. Homology modeling and molecular docking analysis demonstrated that SlCOE030 exhibits effective affinities for cyantraniliprole and nicotine. Thus, insect CarEs may result in the development of cross-tolerance between synthetic insecticides and plant secondary metabolites.

Inducible Cytochrome P450s in the Fat Body and Malpighian Tubules of the Polyphagous Pests of Spodoptera litura Confer Xenobiotic Tolerance

“…To obtain more insights into CYP3- and CYP4-mediated cyantraniliprole tolerance, homology modeling and molecular docking were conducted, which are methods that have been used to provide evidence for the protein involvement in insecticide detoxification. ,,, In this study, SlCYP332A1 , SlCYP6AB12 , SlCYP6AB59 , SlCYP6AN4, and SlCYP340A were selected to perform homology modeling and molecular docking. The results showed that the binding energy between these five P450s and cyantraniliprole ranged from −5.10 to −6.87 kcal/mol.…”

“…The S. litura population was purchased from the Institute of Plant Protection, Academy of Agricultural Sciences of Jilin Province in July 2019, and the larvae and adults were reared under the same conditions which were described in our previous study. 27 All S. litura samples were maintained in our insect garden without any insecticide exposure.…”

“…The ribosomal protein rp49/RpL32 (RpL32) was set as the reference gene for the qPCR analysis (Table S1), and each treatment included three replicates. 27 To examine the tolerance of Drosophila overexpression lines to insecticides, cyantraniliprole was diluted in acetone to six different concentrations (1,2,4,8,16, and 32 mg L −1 for the UAS-CYPs lines and 2, 4, 8, 16, 32, and 64 mg L −1 for the Act5C > UAS CYPs lines), which were then dropped on the pronotum of each fly. Ten 2 day-old virgin flies with straight wing phenotypes were set as one replicate and transferred to a plastic tube containing an artificial diet for the topical bioassay.…”

“…Total RNA from different Drosophila lines was isolated, and qPCR was used to determine the expression of candidate P450s in different Drosophila lines. The ribosomal protein rp49/RpL32 ( RpL32 ) was set as the reference gene for the qPCR analysis (Table S1), and each treatment included three replicates …”

CF2–II Alternative Splicing Isoform Regulates the Expression of Xenobiotic Tolerance-Related Cytochrome P450 CYP6CY22 in Aphis gossypii Glover

“…Further details of the bioassays used are provided in our previous study. 31 The median lethal dose (LD 50 ) and 95% fiducial limits were calculated by probit analysis using SPSS Statistics (IBM SPSS Statistics 26 software, Chicago, IL, USA) and PoloPlus 2.00 software (LeOra Software, USA).…”