花楸树小热激蛋白23.8基因(SpHSP23.8)克隆与表达分析

Cloning and expression analysis on small heat shock protein 23.8 gene(SpHSP23.8)in Sorbus pohuashanensis

以花楸树〔Sorbus pohuashanensis(Hance)Hedl.〕为研究对象,对其小热激蛋白23.8基因(SpHSP23.8)的克隆、组织特异性表达以及响应非生物胁迫的表达进行研究。结果表明:SpHSP23.8基因开放阅读框(ORF)包含648个碱基,编码215个氨基酸,其编码氨基酸序列的理论相对分子质量约23800,该基因包含1个内含子。氨基酸序列比对结果显示:SpHSP23.8蛋白与枇杷〔Eriobotrya japonica(Thunb.)Lindl.〕EjsHSP6蛋白(登录号AKP06201.1)的同源性最高。根据SpHSP23.8蛋白与模式植物小热激蛋白氨基酸序列的聚类分析结果,推测SpHSP23.8蛋白定位于线粒体中。组织特异性表达结果显示:SpHSP23.8基因在茎中的相对表达量最高,其次为果实和根,而花中的相对表达量最低。高温、NaCl及干旱胁迫下,花楸树叶片中SpHSP23.8基因的相对表达量显著升高。随着高温胁迫时间的延长,SpHSP23.8基因的相对表达量呈先升高后降低的变化趋势,且在胁迫2.00 h达到峰值;在NaCl和干旱胁迫下,SpHSP23.8基因的相对表达量均呈升高的变化趋势。高温、NaCl和干旱胁迫下,SpHSP23.8基因在转SpHSP23.8基因拟南芥〔Arabidopsis thaliana(Linn.)Heynh.〕中的表达趋势与其在相应胁迫条件下花楸树中的表达趋势一致。上述研究结果表明:SpHSP23.8基因参与了花楸树对高温、NaCl和干旱胁迫的响应,在花楸树引种驯化的适应性方面起着一定的作用。

Taking Sorbus pohuashanensis(Hance)Hedl.as research object,cloning,tissue-specific expression,and expression in response to abiotic stress of its small heat shock protein 23.8 gene(SpHSP23.8)were studied.The results show that the open reading frame(ORF)of SpHSP23.8 gene contains 648 bases,which encodes 215 amino acids with a theoretical relative molecular mass about 23800,and the gene contains one intron.The amino acid sequence alignment result shows that SpHSP23.8 protein has the highest homology with EjsHSP6 protein(accession No.AKP06201.1)in Eriobotrya japonica(Thunb.)Lindl.Based on the cluster analysis result of amino acid sequence of SpHSP23.8 protein and small heat shock proteins in model plants,it is speculated that SpHSP23.8 protein is located in mitochondria.The tissue-specific expression result shows that the relative expression of SpHSP23.8 gene is the highest in stem,followed by fruit and root,and the lowest in flower.Under high temperature,NaCl,and drought stresses,the relative expression of SpHSP23.8 gene in leaf of S.pohuashanensis increases significantly.With the elongation of high temperature stress time,the relative expression of SpHSP23.8 gene shows a tendency to first increase and then decrease,and reaches the peak value under stress for 2.00 h;under NaCl and drought stresses,that of SpHSP23.8 gene all shows a tendency to increase.Under high temperature,NaCl,and drought stresses,the expression tendency of SpHSP23.8 gene in SpHSP23.8-transgenic Arabidopsis thaliana(Linn.)Heynh.is consistent with that in S.pohuashanensis under corresponding stresses.It is suggested that SpHSP23.8 gene is involved in the response of S.pohuashanensis to high temperature,NaCl,and drought stresses and plays a certain effect in the adaptability of introduction and domestication of S.pohuashanensis.