Resistant Mechanism Of Cytochrome P450 Mediated Schizaphis Graminum On Insecticides

Wheat aphids are one of the most important pests on wheat,which harms the wheat through absorting plant juice directly and spreading the virus indirectly.Thegreenbug,Schizaphis graminum was chosen to study in this study,greenbug treated with imidacloprid or sulfoxaflor after 24 h,the differential expression of P450 genes selected by Illumina RNA sequencing,verification by real-time quantitative PCR and RNAi were conducted,which can explicit the main P450 genes involved in the detoxification of insecticides.The results of the study are as follows:1.The Concentrations of imidacloprid and sulfoxaflor used to treat the greenbug,Schizaphis graminum were screened by leaf-dipping with aphids method.The results showed that LC₅₀ of imidacloprid and sulfoxaflor to were 0.106 mg/L and 0.195 mg/L,respectivel.This provided theoretical basis for concentrations(LC₁₀)in the differential expression of P450genes selected by Illumina RNA sequencing.2.To select differential expression of P450 genes in S.graminumtreated by imidacloprid or sulfoxaflor for 24 h,a transcriptional sequence library and conducting an Illumina RNA-seq sequencing.were conducted.We found that up-regulation of 19 P450 unigenes and up-regulation of 15 P450 unigenes in the greenbug treated by imidacloprid and up-regulation of 18 P450 unigenes and up-regulation of 15 P450 unigenes in the greenbug treated by sulfoxaflor.3.12 P450 genes response to imidaclopridwere determined by qRT-PCR to verify the results of RNA-seq.The results analyzed by RT-qPCR were consistent with DGE library overall?10 unigenes were induced signigicantly by imidacloprid,and 2 unigenes were not induced signigicantly by imidacloprid?.In addition,CYP6A2,CYP6A13,CYP6A14 and CYP4C1 were homologous to the CYP6B and CYP4C genes of the cotton aphid,the P450genes of CYP3 clade and CYP4 clade)were known to be related to insecticide resistance.4.RNA interference?RNAi?technology conducted to clarify whether CYP6A13 was involved in insecticide detoxification or regulation The results showed that The expression of CYP6A13 was significantly reduced in dsCYP6A3-370 and dsCYP6A3-412 greenbug in comparison to control?dsGFP-fed greenbug?at 24 h,respectively after feeding of dsRNA.The efficiency of knockdown of CYP6A13 was relatively stable from 24 to 96 h,and reached maximum at 48 h,the silence efficiency reached 55.1%and 48.5%,respectively.As time went on,the expression of CYP6A13 was relatively stable from 24 to 96 h.The mortality rate of the treatment group?dsCYP6A13-370?at 24,48,72 and 96 h was 3.46,2.61,2.61,1.06-fold compared to the control group?dsGFP?after treatment with imidacloprid for 24 h.the mortality rate of treatment group?dsCYP6A13-412?after treatment with imidacloprid was3.04,2.43,1.12,1.09 and 1.02-fold compared to the control group?dsGFP?after treatment with imidacloprid for 24 h.This indicated that CYP6A13 played a critical role in thethe process of insecticide detoxification or regulation.