Transcriptome Analysis Of Locusta Migratoria Tibetensis Chen (Orthoptera: Oedipodidae) Under Temperature Stress And Heat Shock Protein Gene Expression Analysis

Locusta migratoria tibetensis Chen is one of locust mainly distributed in Tibetan plateau,yarlung zangbo river basin and the western Sichuan plateau of Sichuan,which endangers local gramineous crops and herbages.As the endemic locust species on the Tibetan plateau,the successful growth and breeding of the Tibetan locusts on the Tibetan plateau is inseparable from its adaptation to the temperature environment of the plateau.In order to study the molecular response mechanism of the Tibetan locusts to the plateau temperature,this study conducted a temperature stress test on the Tibetan locusts,setting 40 ℃ high temperature treatment and-5 ℃ low temperature treatment,using 20 ℃ as the control treatment,the treatment time of 1h,to compare and analyze the transcriptome of the Tibetan locusts under the high and low temperature stress.A large number of studies have shown that Heat Shock proteins(HSPs)in the process of insect abiotic stress response to the outside world for the indispensable role.In this study,an Hsp70 and Hsp90 were selected from transcriptome data for amino acid sequence analysis,sets up the 37 ℃,40 ℃,43 ℃high temperature processing and – 5 ℃,2 ℃,1 ℃ low temperature treatment,with20 ℃ as control processing,the processing time for 1 h,3 h,5 h,has carried on the analysis of gene expression.The results are as follows:In this study,a comparative analysis of the transcriptome between high temperature and low temperature of the Tibetan locusts was conducted to explore the molecular response process of the Tibetan locusts to high temperature and low temperature.The results are as follows:1.A total of 66256 unigenes were obtained through RNA-Seq,among which30051 unigenes were successfully annotated.There were,in detail,778 differentially expressed genes(DEGs)at high temperature while 1787 at low temperature.Enrichment analyses performed by GO and KEGG showed that a large number of genes and metabolic pathways regarding to energy metabolism were enriched.Under high temperature,the expression of metabolic synthesis pathways of fatty acids and unsaturated fatty acids was up-regulated and then a great many fatty acids were generated.Moreover,the synthesis and metabolic pathways of amino acids were also up-regulated,after that a variety of amino acids were generated and later consumed.Under low temperature,however,chitinase activity was enhanced,so that it was decomposed into small sugar molecules.Meanwhile,various sugar metabolism pathways were up-regulated,when plenty of small sugar molecules were produced,and then large quantities of alpha-linolenic acid and arachidonic acid were accumulated to maintain normal physiological functions of the cells.These energy metabolism pathways can produce a good number of small molecules of sugar,amino acids,fatty acids and proteins,enhancing Tibetan locusts adaptability to temperature.The analysis of annotated genes found that Heat Shock Proteins(Hsp)were associated with response to temperature stress,mainly involved in the synthesis and transportation of proteins,which prevented protein damage and decomposing of damaged proteins.2.Unigene0047778 and Unigene0035407 were selected from numerous Hsp fragments for sequence analysis.Through BLAST comparison,it was found that the Hsp70 gene similarity between Unigene0047778 and Oxya chinensis was 90.22%,while the Hsp90 similarity between Unigene0035407 and Locusta migratoria was99.42%.Sequence analysis revealed that the amino acid sequence derived from Unigene0047778 contained the signature sequence of Hsp70 family such as DLGTT-S-V、FDLGGGTFDVSIL and EEVD,the amino acid sequence derived from Unigene0035407 contained the signature sequence of Hsp90 family such as YSNKEIFLRE、LGTIAKSGT、IKLYVRRVFI、GVVDSEDLPLNISR and EEVD.Identified that Unigene0047778 as a member of the Hsp70 family and Unigene0035407 as a member of the Hsp90 family.3.To analysis the relative expression of Hsp70 and Hsp90 genes in Tibetan locusts under high temperature and low temperature stress,found that the changes in the relative expression levels of the two genes in male and female adults were similar in pattern and pattern.In high temperature stress,the relative expression of Hsp70 and Hsp90 genes increased with the increase of temperature,while in low temperature stress,the relative expression of Hsp70 and Hsp90 genes decreased with the increase of temperature.The relative expression levels of Hsp70 and Hsp90 genes showed a peak when the duration of temperature stress was 1h or less than 1h,and gradually decrease with time.These results provide a basis for further understanding of the adaptation mechanism of Tibetan locusts to high and low temperatures and lay a foundation for further revealing the adaptability of Tibetan locusts on Tibet Plateau.