小麦质膜Na^+/H^+逆转运蛋白TaSOS1的表达分析

Expression Analysis of Wheat Plasma Membrane Na^+/H^+ Antiporter Gene TaSOS1 at Different Stress Conditions

为探讨小麦质膜Na+/H+逆转运蛋白TaSOS1在逆境条件下的生物学功能,采用荧光定量PCR(RT-PCR)方法,对TaSOS1基因在4种不同胁迫条件下(200mmol.L-1 NaCl、4℃低温、100μmol.L-1ABA和15%PEG6000)的表达水平进行了定量分析。结果表明,在正常条件下,小麦根中TaSOS1的mRNA表达量要高于叶中的表达量。盐胁迫处理下,根中TaSOS1特异性上调表达,说明TaSOS1基因在根中的功能更强,其表达与盐胁迫有关且具有组织特异性;在4℃低温处理下,TaSOS1在叶中上调表达;而在ABA和PEG6000两种处理条件下,TaSOS1的表达没有规律性,推测TaSOS1的表达途径可能为非ABA依赖型且与盐离子的特异性有关。生物信息学分析的结果表明,小麦质膜Na+/H+逆转运蛋白TaSOS1与拟南芥和水稻的质膜Na+/H+逆转运蛋白AtSOS1和OsSOS1具有高度的同源性,由此可以推测小麦TaSOS1具有与AtSOS1和OsSOS1类似的功能,可以把植物体内Na+排出体外,以减轻Na+对植物的毒害。

In order to understand the function of wheat Na＋/H＋ antiporter TaSOS1,Rea1-time quantitative PCR（RT-PCR） was used for identification of relative expression of TaSOS1 at 4 different stress treatments,including 200 mmol·L-1 NaCl,4℃ low temperature,100 μmol·L-1 ABA and 15% PEG6000 treatments.The results showed that at no stress condition,the expression of TaSOS1 in wheat roots was higher than that in wheat leaves.Upon salt treatment,the expression of TaSOS1 was unregulated in wheat roots,which suggested that the expression of TaSOS was salt induced with tissue speciality.The upregulation of TaSOS was observed in wheat leaves treated at low temperature（4oC）.While there were no clear expression tendency of TaSOS1 was observed under the treatments of ABA and PEG6000.To sumarize,the expression of TaSOS1 in wheat was in the ABA-independent pathway and ion-specific which was up-regulated by salt stress.The predicted protein of wheat Na＋/H＋ antiporter gene TaSOS1 shares higher identity in amino acid sequences with proteins coded by the genes of AtSOS1（Arabidopsis thaliana） and OsSOS1（Oryza sativa）,which indicated that the TaSOS1 gene may has similar function as AtSOS1 and OsSOS1 that excluding the excessive Na＋ from the cell and alleviate the toxic damage to wheat plants.