Identification And Expression Profiling Of CYP Genes In Lasioderma Serricorne Via A Transcriptiomic Analysis

The cigarette beetle,Lasioderma serricorne（Coleoptera:Anobiidae）is an important stored product pest with a world-wide distribution.The pest insect is also widely distributed in China.At present,the control of L.serricorne mainly relies on chemical fumigants（such as phosphine）,but due to overuse,L.serricorne has developed strong resistance.At present,pyrethroid insecticides are used as protective agents in some tobacco warehouses at home and abroad to partially replace phosphine.Cytochrome P450 monooxygenases（CYPs）of insects are involved in detoxification metabolism of many insecticides.It is speculated that CYPs of L.serricorne may also participate in detoxification of pyrethroid insecticides.However,there is a lack of research on CYPs of L.serricorne.In this study,we sequenced the transcriptome of L.serricorne larvae,obtained 44 CYPs genes from L.serricorne,and analyzed the expression patterns of CYP4 and CYP6 family genes in response to three pyrethroid insecticides,so as to lay a foundation for further study on the function of CYPs in pyrethroid insecticide carrying metabolism.The results are as follows:1、Sequencing and analysis of the transcriptome of L.serricorneBy using BGISEQ-500 high-throughput sequencing platform,43,634,612 clean reads and 33,222 unigenes were obtained.Based on gene sequences in non redundant（NR）database,25,501 unigenes were annotated.The number of homologous genes between L.serricorne and Tribolium castaneum was the most,accounting for 32.04%.In GO database,17,314 unigenes are annotated successfully,which are distributed in 43 branches of 3categories.The number of unigenes annotated based on KEGG and KOG databases is 22,419and 21,281 respectively,which are distributed in different functional branches.2、Identification and analysis of CYPs gene in L.serricorneA total of 44 CYP genes were retrieved from the transcriptome dataset of L.serricorne.These genes were fall into 4 clusters（clans）:Mitochondrial CYP clan（6 genes）,CYP2 clan（3 genes）,CYP3 clan（24 genes）and CYP4 clan（11 genes）,and could be subdivided into 14families and 28 subfamilies.The conserved domains and phylogenetic tree of the proteins encoded by the CYP genes were analyzed;most of them have conserved domains such as C-helix,K-helix,I-helix,"Meander"region and Haem-binding domain.3、Expression pattern of CYPs gene in L.serricorneThe toxicity of three pyrethroid pesticides to L.serricorne was determined.The results showed that the LC₅₀ of cypermethrin,deltamethrin and permethrin to L.serricorne were94.14,90.79,and 122.01 mg/L,respectively.After treatment with the LC₅₀ concentrations of cypermethrin,deltamethrin,and permethrin,CYP4G249 was increased by 4.7 times,4.44times and 5.64 times,respectively,and CYP6BK29 was increased by 3.46 times,4.98 times and 2.75 times,respectively,compared to those in the control group.The expression of CYP6TE1 was up-regulated by 1.6-fold and 1.97-fold in the treatment of cypermethrin and deltamethrin,respectively,while CYP4BN52 was down-regulated in the treatment of three pyrethroids,CYP4SS1 was down regulated in the treatment of deltamethrin,and CYP6SY1was down regulated in the treatment of permethrin The relative expression was down regulated after treatment.In different developmental stages,the expression level of CYP4SS1was the highest in 5th instar larvae;the expression level of CYP6TE1 was the highest in pupal stage;and the expression level of CYP4G249 was the highest in adult stage.In conclusion,we sequenced the transcriptome of L.serricorne larvae,constructed a transcriptome dataset,identified 44 CYPs genes,and found that three pyrethroid insecticides could induce a significant up-regulation of CYP4 and CYP6 family genes,suggesting that these genes may be involved in detoxification metabolism of pyrethroid insecticides in L.serricorne.This study laid a foundation for exploring the response mechanisms of CYP genes to insecticide stress in L.serricorne.