Study On The Characters And Molecular Mechanism Of Response To Light Stress In Helicoverpa Armigera

Light,is one of the important factors of insect growth and development,such as those be different with their biotope in length and intensity,can do stress for many organisms.The cotton bollworm,Helicoverpa armigera is a typical nocturnal insect,which has a strong phototaxis to artificial light.Light stress can affect their longevity,fecundity and anti-oxidation enzyme system.To date,there are there are few reports on the study on insect response to light stress and phototaxis mechanism.In this study,biological response of H.armigera under light stress were conducted;head transcriptome was built to analyze the differential expressed genes in responding to light stress and characterize their expression;neuropeptide members were identified from transcriptional network and their expression features in response to light stress were described;Expressions of Heat shock protein in H.armigera and Drosophila melanogaster in response to light stress were compared.These results should help to illuminate the characteristics and molecular mechanisms of H.armigera in response to light stress,provide the theory basis for the research on phototaxis mechanism of insect.The main conclusions are as follows: 1 Effects of UV light stress on life of H.armigeraThis study determined the long time UV light stress on life,laying eggs,larvae and pupae development in H.armigera,the results showed that the under the light of the long-term light stress,adults,larvae and pupae developmented more long period than the control group significantly,there are no difference in the total oviposition number between two groups.Pupal cooling point of light stress group rise obviously,which indicates that light stress may effect other stressresistance.2 Head transcriptome and differentially expressed gene analysis responsible for light stress response in H.armigeraHead from H.armigera in response to UVA,white and dark control were used to construct transcriptome.After assembling all samples together and filtering the abundance,we got 52,513 Unigenes.Unigenes by aligning with 7 functional databases.Finally,27,958(NR: 53.24%),17,105(NT: 32.57%),18,347(Swissprot: 34.94%),19,031(KOG: 36.24%),19,797(KEGG: 37.70%),143(GO: 0.27%),and 19,167(Inter Pro: 36.50%)unigenes are annotated.According to differential genes expression analysis,both UVA and white showed significant differential genes expression comparing with dark control.UVA treatment had 33761 down-regulated gene and17087 up-regulated gene.The total number of differential expression gene were 50848.Among them,the annotated gene as p450,heat shock protein and neuropeptide were 117,62 and 13,respectively.These data provided valuable sequence database at transcriptional level under light stress,which significantly contributes to analyze light stress relative pathways and biological processes in H.armigera.3 Expressions of neuropeptides in H.armigera in response to light stress We identified 34,17,and 58 unigenes annotated as neuropeptides and peptide hormones,neurotransmitter precursor processing enzymes,respectively.Under light stress,there were sex-specific differences in gene expression.The IMFamide,leucokinin and s NPF genes were differentially expressed at the m RNA level in males but not in females in response to light stress.4 Expressions of Heat shock protein in H.armigera and Drosophila melanogaster in response to light stress We identified 11 H.armigera Hsp genes,including Hsp19.5(KX845558)?Hsp19.7(KX845559),Hsp20.0(KX845560),Hsp20.7(KX845561),Hsp20.8(KX845562),Hsp21.4(KX845563),Hsp22.0(KX845564),Hsp27.2(KX845565),Hsp60(KX845566),HSC70(KX845566)and(KX845566).Then we tested the temporal expression patterns of H.armigera Hsps under light stress as well as D.melanogaster Hsps.The results indicated that each Hsp had a differential temporal expression profile under light stress.So Hsps might act in a coordinated and cooperative manner at the transcriptional level to counteract light stress.Potential transcription factor-binding motifs(TFBMs)in the promoter regions of strongly inducible Dm Hsps were identified,results showed these TFBMs were highly homologous to binding sites that have been identified for transcription factors associated with light stress stimuli.