Transcriptome Analysis Of The Bamboo Locust,Ceracris Kiangsu(Acrididae:Orthoptera) And Its Molecular Mechanism For Hypothermic Stress Acclimation

The locust widely distributed in China from high temperature plains to low temperature plateaus.The bamboo locust Ceracris kiangsu is a pest of bamboos.However,the underlying mechanisms of hypothermic stress acclimation in C.kiangsu are unclear.There are no research reports related to low temperature stress.Thus high-throughput sequencing is needed to generate a number of transcriptome sequences to be used for gene discovery and molecular marker development.In this study,high-throughput sequencing was used to analyze the global transcriptome of C.kiangsu.The main results and conclusions are as follows:1)Approximately 129,314,084 reads were generated using Illumina HiSeq 2000.De novo assembly with paired-end information yielded 39,013 unigenes with an average length of 987.221 bp.Based on sequence similarity searches with known proteins,a total of 19,769(50.67%)unigenes were identified.Of these annotated unigenes,11,412 unigenes were assigned to clusters of gene ontology(GO).The biological process(G0:008150)occupied the main part for 43%,the cellular component(G0:005575)occupied for 30.45%,and the molecular function(GO:0003674)occupied for 26.55%.In the global transcriptome of C.kiangsu we found a total of 22 genes in the heat shock proteins(Hsp)gene family,they were Hsp70,Hsp90,Hsp20,Hsp20.5,Hsp20.6 and Hsp20.7.What is more,we found a total of 8,354 genes and 291 metabolic pathways in the Kyoto Encyclopedia of Genes and Genomes(KEGG).In addition to 11 metabolic pathways only contain one gene,the other pathways could contain 2 or more genes,and the most is up to 2,066 genes,whichis mainly responsible for the catalytic activity.2)The locust species exhibits adaptation to low temperatures through regulatory pathways leading to a decrease in metabolic activity,energy production,and synthesis of a large number of Hsp genes.Differences were observed in gene expression after hypothermic stress,with the most up-regulated genes including heat shock proteins and genes involved in ATP binding.The down-regulation of genes was mainly involved in the catalytic activity of metabolic mechanisms.Hsp70 and Hsp90 were the most cold-inducible,and the Hsp90 gene was the first reported in locust response to low temperature.The small Hsps(sHsps)family(Hsp20.6,Hsp20.7)showed a similar quantity of expression during hypothermic stress.Only a few studies to date have analyzed the expression of genes in the sHsps family in relation to cold stress in insects.3)We could find the ML tree based on Hsp 70 and Hsp90 family that the phylogenetic relationship between Hsp70 and Hsp90 was closed,and they were far form the small Hsps gene family.4)In the Hsp90 tree,Hsp90-1 and Hsp90-2 genes which have the same expression in differential gene expression after hypothermic stress have closed relationship.However,Hsp90-3 was far away form the other two genes based on the gene founction.