中国南瓜CmHSP90基因的克隆及其在逆境胁迫下的表达分析

Cloning of CmHSP90 Gene in Cucurbita moschata and Its Expression Analysis under Several Adversity Stresses

热激蛋白90(heat shock protein 90,HSP90)广泛介导胁迫信号的传递,在植物逆境应答反应中起重要作用。为探究HSP90基因的功能,该研究采用RT-PCR方法从中国南瓜(Cucurbitamoschata)幼苗中分离到2个HSP90基因的开放阅读框(ORF)全长,分别命名为CmHSP90-5和CmHSP90-6。二者的序列长度分别为2357和2472 bp,编码793和824个氨基酸。蛋白序列分析显示,2个CmHSP90蛋白均属于亲水性蛋白,含信号肽,无跨膜区,结构上都含有典型的ATPase保守结构域,亚细胞分别定位于叶绿体和线粒体。同源比对和进化分析发现,2个CmHSP90蛋白与苦瓜(Momordica charantia)、甜瓜(Cucumis melo)和黄瓜(Cucumis sativus)HSP90蛋白的相似性最高且遗传距离最近。qRT-PCR分析显示,2个CmHSP90基因对高温、低温、ABA、高盐、H2O2、干旱和水杨酸(SA)等多种胁迫均具有明显的应答反应,但响应的速度和强度并不相同,其中对高温和水杨酸处理均表现出短时间强烈响应,推测CmHSP90基因可能在中国南瓜热胁迫和水杨酸信号途径中发挥调节作用。该研究结果为深入了解HSP90基因功能以及阐明中国南瓜的抗逆机制提供理论依据。

HSP90(Heat shock protein 90)widely mediates stress signal transduction and plays an important role in plant stress response.In order to investigate the function of HSP90 gene in Cucurbita moschata,we isolated the ORFs(open reading frames)of two HSP90 gene from Cucurbita moschata seedling using RT-PCR method and named CmHSP90-5 and CmHSP90-6.Their sequence length were 2357 and 2472 bp,encoding 793 and 824 amino acids,respectively.Protein sequence analysis showed that both CmHSP90 were hydrophilic proteins with signal peptide and no transmembrane region.They all contain typical conserved domains of ATPase and subcells were located in chloroplasts and mitochondria,respectively.Homologous comparison and evolutionary analysis revealed that two CmHSP90 had the highest consistency with the HSP90 of Momordica charantia,Cucumis melo and Cucumis sativus,and the genetic distance was the closest.The qRT-PCR analysis showed that both Cm HSP90 genes were induced by hot,cold,ABA,high-salt,H2 O2,drought and SA(salicylic acid)treatments,but the response speed and intensity were not the same.Specifically,two genes responded strongly to hot and salicylic acid treatments for a short time.It is speculated that CmHSP90 gene may play a regulatory role in heat stress and salicylic acid signal pathway of Cucurbita moschata.The results provided a theoretical basis for further understanding the function of HSP90 and elucidating the stress resistance mechanism of Cucurbita moschata.