Qiao Wei Hua, Zhao Xiang Yu, Li Wei, Luo Yan, Zhang Xian Sheng
College of Life Sciences, Peking University, Beijng 100871, China.
Plant Cell Rep. 2007 Sep;26(9):1663-72. doi: 10.1007/s00299-007-0354-3. Epub 2007 Apr 17.
Agropyron elongatum, a species in grass family, has a strong tolerance to salt stress. To study the molecular mechanism of Agropyron elongatum in salt tolerance, we isolated a homolog of Na(+)/H(+) antiporters from the root tissues of Agropyron plants. Sequence analysis revealed that this gene encodes a putative vacuolar Na(+)/H(+) antiporter and was designated as AeNHX1. The AeNHX1-GFP fusion protein was clearly targeted to the vacuolar membrane in a transient transfection assay. Northern analysis indicated that AeNHX1 was expressed in a root-specific manner. Expression of AeNHX1 in yeast Na(+)/H(+) antiporter mutants showed function complementation. Further, overexpression of AeNHX1 promoted salt tolerance of Arabidopsis plants, and improved osmotic adjustment and photosynthesis which might be responsible for normal development of transgenic plants under salt stress. Similarly, AeNHX1 also functioned in transgenic Festuca plants. The results suggest that this gene might function in the roots of Agropyron plants, and its expression is involved in the improvement of salt tolerance.
长穗偃麦草是禾本科的一个物种，对盐胁迫具有很强的耐受性。为了研究长穗偃麦草耐盐的分子机制，我们从长穗偃麦草植株的根组织中分离出一种Na(+)/H(+)逆向转运蛋白的同源物。序列分析表明，该基因编码一种假定的液泡Na(+)/H(+)逆向转运蛋白，并被命名为AeNHX1。在瞬时转染实验中，AeNHX1-GFP融合蛋白明确靶向液泡膜。Northern分析表明，AeNHX1以根特异性方式表达。AeNHX1在酵母Na(+)/H(+)逆向转运蛋白突变体中的表达显示出功能互补。此外，AeNHX1的过表达提高了拟南芥植株的耐盐性，并改善了渗透调节和光合作用，这可能是转基因植株在盐胁迫下正常发育的原因。同样，AeNHX1在转基因羊茅植株中也发挥作用。结果表明，该基因可能在长穗偃麦草植株的根中发挥作用，其表达参与了耐盐性的提高。
