中文摘要：

【目的】近年来,大螟Sesamia inferens（Walker）对水稻的为害逐渐加重并成为水稻的重要害虫之一。随着全球气候变暖,大螟的分布区域也在逐渐向北延伸。HSP70家族作为分子伴侣参与生物生长发育并对外界刺激产生响应,对生物功能蛋白质的正确折叠及其转运有着重要意义。本研究旨在明确HSP70家族HSC70基因在大螟不同组织、不同发育阶段以及低温胁迫下的表达差异,初步探讨大螟对环境适应的分子机理。【方法】应用RT-PCR及RACE技术从大螟5龄幼虫中克隆得到HSC70基因;进行基因组验证,得到其基因组序列,分析内含子的位置及大小;应用实时定量PCR技术分析大螟HSC70基因的表达模式。【结果】大螟HSC70基因长2 160 bp,命名为Sihsc70（GenBank登录号：KJ639908）,开放阅读框长1 962 bp,编码653个氨基酸,推测分子量为71.6 kDa。其氨基酸序列中含有3个HSP70家族保守序列,在C-末端存在细胞质定位信号,说明大螟HSC70是细胞质热激蛋白家族成员。大螟HSC70基因组序列长度为3 522 bp（GenBank登录号：KJ639909）,含有2个内含子,长度分别为685 bp（位于编码区上游）和803 bp（位于编码区内）。在大螟5龄幼虫的不同组织中Sihsc70表达量差异不显著（P〉0.05）,其中在中肠、后肠和体壁中的表达量较高,在唾腺中的表达量最低;在大螟不同发育阶段中,Sihsc70的表达量在雌成虫最低,较高的3个阶段依次为卵、2龄幼虫和5龄幼虫,分别为雌成虫表达量的6.33,3.21和1.86倍;相对于对照组（27℃）,低温胁迫对大螟5龄幼虫HSC70基因表达的影响差异不显著（P〉0.05）。【结论】结果说明,大螟HSC70基因在不同发育阶段和幼虫不同组织中具有不同的表达水平,而低温胁迫不能诱导该基因大量表达。

英文摘要：

【Aim】In recent years,the pink borer,Sesamia inferens（ Walker） has become one of the major pests of rice with its damage increasing. With the global warming,it is further dispersing northward. Heat shock protein 70（ HSP70） family is of great significance for the correct fold and transmission of proteins in organisms. HSP70 participates in growth and development of organisms as chaperones,and causes responses to external stimuli. Our study aims to understand the expression differences of HSC70 gene from S. inferens in different tissues,in different developmental stages and under low-temperature stress,and to explore the molecular mechanisms of environmental adaptability of S. inferens. 【Methods】RT-PCR and RACE were used to clone the full-length cDNA of HSC70 gene from the 5th instar larvae of S. inferens. The genomic sequence was demonstrated by genomic validation and intron was analyzed by sequence analysis of cDNA. The expression patterns of HSC70 gene were investigated by real-time quantitative PCR. 【Results】The complete cDNA sequence was obtained and named as Sihsc70（ GenBank accession no. ： KJ639908）,which is 2 160 bp in length,containing an opening reading frame（ ORF） of 1 962 bp and encoding 653 amino acid residues with the predicted molecular weight of 71. 6 kDa. Three conserved sequences of HSP70 family exist in its amino acid sequence. The cytoplasmic localization signal in C-terminus indicated that S. inferens HSC70 is a cytoplasmic heat shock protein. Analysis of genomic DNA sequence（ GenBank accession no. ：KJ639909） demonstrated that HSC70 gene contains 2 introns. The 1st intron,685 bp in length,is located upstream of the coding region. The 2nd intron,803 bp in length,is located in the coding region.The expression levels of Sihsc70 were not significantly different among different tissues of the 5th instar larva（ P 〉 0. 05）,with the higher expression levels in midgut,hindgut and epidermis,and the lowest in salivary glands. Sihsc70 had the lowest expression level