盐穗木水通道蛋白基因的克隆与功能鉴定

Cloning and Function Identification of an Aquaporin Gene from Halostachys caspica

非生物胁迫(如盐渍和干旱)会引起植物水分代谢的紊乱,导致植物细胞水分丧失,直接抑制植物的生长发育。研究水通道蛋白(aquaporins,AQPs)在非生物胁迫下对植物生理功能的影响十分重要。本研究利用RACE技术克隆获得一个盐穗木(Halostachys caspica)水通道蛋白家族亚类质膜内嵌蛋白(plasma intrinsic protein,PIPs)基因,命名为Hc PIP1。Hc PIP1基因全长序列为1 244 bp,包含858 bp的开放阅读框(open reading frame,ORF)序列,编码285个氨基酸,分子量大小约为30.6 k D。q RT-PCR检测表明Hc PIP1在盐穗木根部的表达量显著高于同化枝中,盐胁迫诱导其上调表达。在酿酒酵母INVSc1中Hc PIP1的异源过表达显著提高了重组菌的耐盐能力;和野生型植株相比过表达Hc PIP1的拟南芥能够显著缓解渗透胁迫和离子胁迫对生长的抑制,并且根长明显比野生型的长。结果表明Hc PIP1在胁迫时能够通过增加根的生长以抵御胁迫的影响。

In the majority of abiotic stress conditions such as salt and drought will cause the dehydration of the plant cells and inhibition of plant growth and development, it is important to study influence of AQPs on the physiological function of plant under the abiotic stress. A novel aquaporin gene designated HcPIP1 was isolated from Halostachys caspica using RACE method. The ORF of HcPIP1 was 858 bp encoding 285 amino acids, the molecular weight is 30.6 kD. HcPIP1 shared high sequence identity with PIPls identity with capacity. Localization analysis showed that HcPIP1 proteins tagged with green fluorescent protein （GFP） were localized to the cell plasma membrane of the transgengic A rabidopsis. The growth oftransgenic plants and WT was suppression under osmotic stress and ion stress conditions, but the restraining degree of transgenic plants was lower than WT, overexpression of HcPIP l in A robidopsis has a better phenotype and increased root elongation compared with WT under osmotic stress and salt stress, but in the absence of stress control conditions, there was no significant difference in growth between transgenic plants and WT. Our results suggested that HcPIP 1 played an important role in salt tolerance and can also enhance plants＇ tolerance to other abiotic stresses.