Identification And Expression Of Olfactory Genes In Hyphantria Cunea (Drury)

Insects have evolved an extremely sensitive and sophisticated olfactory system during the lengthy evolution history.Within the species specific olfactory-sensory mechanism,insects can finish various physiological behaviors,such as finding hosts,mates,foraging and ovipositing sites and phobotaxis by sensing and recognizing pathognostic odorants from external environment.Therefore,as an intermediary during the chemical communication,insect sex pheronmones and various plant volatiles play a vital role in insect olfaction process.Hyphantria cunea(Drury)is a worldwide quarantine pest,its rapidly spreading has caused unprecedented economic losses and great ecological disasters.It has been listed as one of the most important invasive pests nationwide in China,due to the severe control situation.Compared to the better known Type-I lepidopteran pheromone using species,little is known at the molecular level about the olfactory mechanisms in H.cunea,a Type-?lepidopteran pheromone using species.Thus,it is essential to discover the molecular mechanisms of olfaction in H.cunea,especially the mechanisms of sex pheromone communications,which provide new scientific methods to control H.cunea.In the present study,the H.cunea antennal transcriptome was constructed by Illumina sequencing,olfaction-related genes were identified with the bioinformatics method.Then the expression patterns of olfactory genes were conducted in different tissues.The results are as follows: 1.Antennae transcriptome sequencing and bioinformatics analyzing in H.cunea:(1)A total of 64,020,776 clean reads and about 8G bases were abtained from the H.cunea antennae transcriptome.59,243 unigenes were selected from the 78,131 transcripts which assembled by Trinity.15,242 unigenes were annotated in the Nr database.As a result,the species classification showed that the best match was Bombyx mori,representing 48.10%,followed by Danaus plexippus(29.50%).(2)A total of 12,565 unigenes were assigned to three main GO classes among all 59,243 unigenes.After a total of 5,781 unigenes were annotated in the KO database,a KEGG pathway classification were abtained.(3)Among all 59,243 unigenes,7,708 unigenes had a FPKM value over 10 with a relatively high gene expression level.The 50 most abundant expressed unigenes represent 7 OBP(Odorant binding protein)and 2 CSP(Chemosensory protein).2.The identification and expression of olfactory genes in H.cunea:(1)30 putative Odorant binding proteins(OBPs),17 putative Chemosensory proteins(CSPs),52 putative Odorant receptors(ORs),10 putative Carboxylesterases(CXEs),two putative Sensory neuron membrane proteins(SNMPs),9 putative Gustatory receptors(GRs)and 10 Ionotropic receptors(IRs)were identified by analyzing the antennae transcriptome.(2)Reverse Transcription PCR(RT-PCR)and Quantitative Real-time PCR(RT-qPCR)results showed that: some OBPs displayed highly antennae biased expression,3 PBPs were highly male antennae biased expressed;CSPs displayed a wide range of expression distribution;HyphOR27(ORco)were highly expressed in antennae,and 3 PRs were highly male antennae biased expressed;CXEs displayed a differential highly expression in antennae of both sexes;HyphSNMP1 were highly female antennae biased expressed while HyphSNMP2 displayed highly male antennae biased expression.This study is the first identification of olfactory genes in H.cunea.Expression patterns of olfactory genes revealed the expression differential in different tissues of both sexes.These researches provided better understanding of molecular mechanisms of sex pheromone communications in H.cunea and theoretical bases for scientific controlling H.cunea.These results have greatly expanded olfactory mechanisms research in the Type-?lepidopteran pheromone using species.