新疆盐生植物车前PmNHX1基因的克隆及生物信息学分析

盐分对植物的伤害主要是Na+引起的，而Na+/H+逆向运输蛋白催化Na+/H+逆向跨膜运输，从而使质膜上Na+运出细胞和液泡膜中的Na+区隔化。这是植物尤其是盐生植物抵御盐胁迫的主要方式之一。根据不同植物编码液泡膜逆向运输蛋白基因的保守序列，设计简并引物，采用RT-PCR和RACE技术，首次从新疆盐生植物车前（Plantago maritima）中克隆到Na+/H+逆向运输蛋白基因的cDNA全长2464 bp，命名为PmNHX1(GenBank登录号：EU233808)，该基因编码区长为1 662bp，编码553个氨基酸，理论分子量为61.16kDa，等电点为7.22。数据分析结果显示，该蛋白质主要定位于液泡膜上，由12个序列保守的跨膜结构域组成，其中TM3跨膜结构域上存在“LFFIYLLPPI”-氨氯吡嗪咪结合域，并且该位点与Na+有竞争作用。PmNHX1逆向运输蛋白与其他植物逆向运输蛋白的氨基酸同源性为64％~80％。通过生物信息学方法对其理化性质和功能分析进行预测，这为进一步研究转耐盐基因PmNHX1及其功能鉴定奠定了基础。

Cloning and Bioinformatics Analysis of PmNHX1 gene fromXinjiang Halophyte Plantago maritima

The salt damage to the plants is mainly caused by Na+. The catalytic transport of Na+/H+antiporter protein causes Na+ to come out of the Na+ compartmentalization of the vacuole membrane and the plasma membrane of the cell. The halophyte plants have been found to be resistant to salt stress caused by Na+. The conservative transport protein gene sequence of halophyte, Plantago maritima was carried out first time at Xinjiang by using RT-PCR and RACE technology and cloned into the Na+/H+ antiporter transport protein gene (2464 bp full-length cDNA) named as PmNHX1 (GenBank accession number: EU233808).It was found that the head of the gene consist the coding of the 1662 bp which encoded 553 amino acids. It had the molecular weight of 61.16 KDa and isoelectric point was 7.22. The data analysis showed that the protein mainly located in vacuole membrane was from 12 conservative sequence of the transmembrane domain of which the TM3 transmembrane domain (LFFIYLLPPI - putative amiloride binding domain) was found to be responsible for playing a competitive role. The amino acid homology of PmNHX1 and other plants antiporter protein was 64% - 80%. Due to its unique ability to find out physical and chemical properties and forecast the function of the gene, the use of bioinformatics methods laid the foundation for study related to identification of the salt-tolerant gene function of PmNHX1.