Identification And Expression Profiling Of Olfactory-related Genes In Sitophilus Zeamais(Coleoptera:Curculionidea) Using QRT-PCR

The maize weevil is a worldwide grain storage pest and also as the largest storage pests in China,which mainly harms stored grain and processed products.This paper makes a preliminary study on the morphology of the antennae and its sensilla,transcriptome analysis and qRT-PCR.The research results were as follows:1.Scanning electron microscope was used to observe and identify the antennae ultrasensory structures of male and female adult maize weevil,and Y-shaped olfactory apparatus was used to detect the behavior and reaction of maize weevil to different volatiles.The antenna of the adult maize weevil is geniculate and consists of a scape,a pedicel and a 6-antennomere flagellar.The total length of antennae was 781.58 ± 20.64 ?m for male and 808.91±11.8 ?m for female.Four types of antennae sensilla were identified:sensilla squamiformia SS(mechanoreceptor),sensilla chaetic SC(contact chemoreceptor),sensilla basiconic SB(olfactory chemoreceptor)and sensilla coeloconic SCo(wet sensor).The behavior experiment showed that the volatile matter of wheat had strong attraction to the normal male and female adult maize weevil,and the insect pheromone had attraction to the normal male and female adult maize weevil.Antennae play a crucial role in the maize weevil's food search and pheromone identified.2.RNA sequencing was performed on the adult maize weevil antennae through transcriptome sequencing technology.The overall assembly was completed,and the antennae transcriptome of the maize weevil was annotated and analyzed as a whole.A total of 21,587,928 raw reads and 21,046,498(97.49%)high-quality clean reads were obtained from antennal transcriptome,and 52,206 Unigenes were successfully assembled.The average length of Unigenes is 764bp,of which N50 is 1288 bp.The 11028 Unigenes(21.12%)exceeded 1000bp.The annotation results showed that at least 27,714 Unigenes(53.08%)were successfully annotated.The sequence of maize weevil antennal transcriptome was completed and the sequence information of maize weevil gene was obtained.The antennal transcriptome data of the maize weevil had been uploaded to the NCBI dataset sequence archive(SRA database)SRX3427302.3.Bioinformatics and molecular biology technology methods were used to study the antennal transcriptome data of maize weevil,identify olfactory related genes,and complete the expression pattern analysis.A total of 41 odorant binding protein genes were identified,18 of which were highly expressed in antennae.There were 64 odorant receptor protein genes,53 of which were highly expressed in antennae.Four sensory neuronal membrane protein genes were highly expressed in antennae.There were 13 chemoreceptor genes,6 of which were highly expressed in antennae.There were 20 ionotropic receptor genes,12 of which were highly expressed in antennae.It is speculated that these highly expressed olfactory genes in the antennae of olfactory tissues may play an important role in the olfactory of maize weevil.