Overexpression of a tonoplast Na+ /H+ antiporter from the halophytic shrub Nitraria sibirica improved salt tolerance and root development in transgenic poplar
Overexpression of a tonoplast Na+ /H+ antiporter from the halophytic shrub Nitraria sibirica improved salt tolerance and root development in transgenic poplar
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盐生灌木白刺 (Nitraria sibirica) 的液泡膜 Na /H 逆向转运蛋白的过度表达改善了转基因杨树的耐盐性和根系发育
DOI：
10.1007/s11295-020-01475-7
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发表时间：
--
影响因子：
2.4
通讯作者：
林晓飞
中科院分区：
文献类型：
--
作者：
耿新;陈首业;鄂一岚;张文波;毛惠平;阿拉坦其其格;王迎春;祁智;林晓飞
钠/质子交换器（NHX）介导植物体内Na+和H+的逆向运输，在调节细胞内pH值、维持离子和渗透平衡等方面起着重要作用。NHX 1的同源基因NsNHX 1在盐生植物西伯利亚白刺（Nitraria sibirica Pall）中被分离得到，并在提高转基因拟南芥耐盐性方面发挥了重要作用。为了进一步分析NsNHX 1启动子的特性和功能，克隆了NsNHX 1启动子的1311 bp序列，组织化学染色结果表明，NsNHX 1启动子驱动的β-葡萄糖醛酸酶（GUS）表达受非生物胁迫和植物激素如作为盐、干旱、赤霉素和茉莉酸甲酯的强烈诱导，进而表明NsNHX 1可能参与多种信号通路的调控。为了研究NsNHX 1基因对林木耐盐性的调控作用，将NsNHX 1基因导入84 K白杨，对转基因杨树的耐盐性分析表明，NsNHX 1基因的过量表达提高了杨树的生物量、存活率、株高以及叶绿素、脯氨酸和水分含量，这些都是盐胁迫下抗氧化酶活性的结果。这表明，NsNHX 1的过表达增强了转基因杨树的耐盐性，由于NsNHX 1介导的Na+区室化，更有效的光合作用，更大的抗氧化酶活性，并改善渗透调节。此外，NsNHX 1的过表达增强了转基因杨树的根系发育，这可能是由于NsNHX 1与膜质子泵之间的耦合作用，导致了在正常和盐胁迫条件下杨树的生物量和高度增加。这些结果为进一步了解NsNHX 1的功能和调控机制以及在林木遗传改良中的应用提供了理论和实验基础。
The sodium/proton exchanger (NHX) mediates Na+and H+countertransport in plants and plays an important role in regulating intracellular pH and maintaining ion and osmotic balance. Previously, anNHX1orthologue was isolated from the halophyteNitraria sibiricaPall (referred to asNsNHX1), and its role in enhancing salt tolerance of transgenicArabidopsiswas confirmed. To further analyse its features and functions, the 1311-bp sequence of theNsNHX1promoter was cloned, and histochemical staining showed that β-glucuronidase (GUS) expression driven by theNsNHX1promoter was strongly induced by abiotic stress and phytohormones, such as salt, drought, gibberellins, and methyl jasmonate, in turn indicating thatNsNHX1might participate in the regulation of various signalling pathways. To determine howNsNHX1regulates salt tolerance in forestry trees,NsNHX1was introduced into 84K poplar, and salt tolerance analysis of transgenic poplars showed that overexpression ofNsNHX1increased the overall biomass, survival rate, and plant height, and the contents of chlorophyll, proline and water, all of which are consequences of antioxidant enzyme activity under salt stress conditions. This showed that overexpression ofNsNHX1enhanced the salt tolerance of transgenic poplars as a result of NsNHX1-mediated Na+compartmentalisation, more efficient photosynthesis, greater activity of antioxidant enzymes, and improved osmotic adjustment. Moreover, overexpression ofNsNHX1enhanced the root development of transgenic poplars; this resulted in increased biomass and height under normal and salt stress conditions, likely due to coupling between NsNHX1 and membrane proton pumps. These results provided a theoretical and experimental basis for further understanding the function and regulatory mechanism ofNsNHX1, as well as its application for genetic improvement of forestry trees.