Insecticide Resistance-related Gene Family Analysis And Database Construction Of Chilo Suppressalis

With the rapid development of sequencing technology,the cost of sequencing has been reduced dramatically.An increasing number of genomes and transcriptomes have been sequenced for tens of insects,which provide the rich data sources for entomological research.With assistance of big data in the entomology,some novel pest control methods have been developed such as RNAi-pest control.The rice stem borer(SSB),Chilo suppressalis,is an important rice insect pest,which causes huge economic loss in agricultural production.The chemical pesticides have been largely used to control this notorious pest.However,over-use of insecticides resulted in the serious problem of resistance.With the SSB genome,we carried out genome-wide analysis of insecticide resistance associated gene families and constructed a gene data of C.suppressalis:1.Genome-wide analysis of resistance-related gene family in C.suppressalisThe genome sequences of silkworm,Monarch Butterfly,diamondback moth,muse sleeves butterflies were used for comparative analysis.These four insects were economic insects,ornamental insect,vegetable pests,rice pests,which face different insecticide selection pressures.By searching the genome,we obtained 12 carboxylesterase genes,108 cytochrome p450s,16 glutathione S-transferases,32 acetylcholine receptors,10 sodium channels,6 ?-aminobutyric acids,27 ryanodine receptor,yielding 211 insecticide resistance associated genes in total.We also found the Bt receptor genes including 5 alkaline phosphatases,14 aminopeptidase N,33 cadherin,14 glycosyltransferase enzymes in the SSB genome,producing a total of 66 genes.Compared with the other four Lepidoptera insects,ryanodine receptors and aminopeptidase N gene family showed significant expansion,suggesting that SSB has high potentiality to develop resistance to chlorantraniliprole and Bt toxin protein.The cytochrome P450 gene family also shows obvious expansion,suggesting that metabolic detoxification could be the main reason in insecticide resistance of SSB.2.The expression of insecticide resistance associated genes in the midgut of SSBThe midgut is the main tissue absorbing the food and taking in the chemical insecticides.So,it is important to study the expression of insecticides resistance associated genes in the midgut.We have obtained the midgut transcriptome in a previous work.To study the tissue specific gene expressions in the midgut,we chose the eggs,mixing larva,pupa and adult to form a mixed sample and sequenced the transcriptome.The differential gene expression analysis indicated that 21 genes were up-regulated and 192 genes were down-regulated in the midgut.Among which,one up-regulated gene is insecticide resistance associated,glutathione S-transferase.Nineteen genes down-regulated genes were insecticide resistance genes including five P450s,four acetylcholine receptors and four ryanodine receptors genes.There was not any Bt resistance associated gene was differentially expressed in the midgut.The results showed that most resistance associated genes were normally expressed under normal circumstances.After the stimulation by pesticides,the expression would be activated.3.ChiloDB:a genomic and transcriptome database of SSBChiloDB is an integrated resource that will be of use to the rice stem borer research community.ChiloDB aims to(i)store genomic sequence and transcriptome data and integrate them with protein coding genes,microRNAs,piwi-interacting RNAs(piRNAs)and RNA sequencing(RNA-Seq)data,(ii)provide comprehensive search tools and downloadable data sets for comparative genomics and gene annotation of this important rice pest.ChiloDB contains the first version of the official SSB gene set,comprising 80479 scaffolds and 10221 annotated protein-coding genes.Additionally,262 SSB microRNA genes,82639 piRNAs,37040 transcripts from a midgut transcriptome and 69977 transcripts from a mixed sample have all been integrated into ChiloDB.ChiloDB was constructed using a data structure that is compatible with data resources,which will be incorporated into the database in the future.This resource will serve as a long-term and open access database for research on the biology,evolution and pest control of SSB.To the best of our knowledge,ChiloDB is one of the first genomic and transcriptome database for rice insect pests.The database was online for service since August 2014,researchers from 70 countries has been accessed the website,and provides important data platform for stem borer study.