OsNHAD is a chloroplast membrane-located transporter required for resistance to salt stress in rice (Oryza sativa)
OsNHAD is a chloroplast membrane-located transporter required for resistance to salt stress in rice (Oryza sativa)
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OsNHAD 是水稻 (Oryza sativa) 抵抗盐胁迫所需的叶绿体膜转运蛋白
DOI：
10.1016/j.plantsci.2019.110359
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发表时间：
2020-02-01
期刊：
影响因子：
5.2
通讯作者：
Yang, Zhi Min
中科院分区：
文献类型：
--
作者：
Liu, Xue Song;Feng, Sheng Jun;Yang, Zhi Min
盐胁迫是限制作物产量的主要环境因子之一。虽然植物盐胁迫响应的生理和分子表征一直是人们关注的焦点，但植物，特别是粮食作物（如水稻）中钠离子（Na+）吸收、转运和积累的转运蛋白的研究有限。在这项研究中，我们功能上确定了一个未知的钠离子转运蛋白命名为OsNHAD，它编码一个假定的Na+/H+反向转运蛋白在水稻。同源性分析表明该基因与拟南芥Na+/H+逆向转运蛋白AtNHD 1同源性为72.74%。OsNHAD转录本主要在叶片中表达，受Na胁迫诱导表达。对烟草叶片中OsNHAD：：GFP融合体的共聚焦激光扫描显微镜分析显示OsNHAD存在于叶绿体被膜中。RNA干扰敲低OsNHAD基因可导致水稻对Na+的敏感性增加，表现为植株生长受阻、细胞损伤加重、PSII活性降低和叶绿体形态改变。OsNHAD基因的突变也导致了叶绿体和地上部Na+的积累，表明OsNHAD基因参与介导Na+的外排和解毒，但不影响植物细胞中K+的积累。互补试验表明OsNHAD能够在功能上恢复拟南芥atnhd 1 -1突变体的生长表型。这些结果表明，OsNHAD可能介导的钠离子在亚细胞区室和组织的植物在盐胁迫下的动态平衡。
Salt stress is one of the major environmental factors limiting crop productivity. Although physiological and molecular characterization of salt stress response in plants has been the focus for many years, research on transporters for sodium ion (Na+) uptake, translocation and accumulation in plants, particularly in food crops like rice is limited. In this study, we functionally identified an uncharacterized sodium ion transporter named OsNHAD which encodes a putative Na+/H+ antiporter in rice. Homology search shows its close relation to the Arabidopsis Na+/H+ antiporter AtNHD1 with 72.74% identity of amino acids. OsNHAD transcripts mainly express in leaves and are induced by Na stress. Confocal laser scanning microscopy analysis of OsNHAD::GFP fusion in tobacco leaves shows that OsNHAD resides in the chloroplast envelop. Knock-down of OsNHAD by RNA interference led to increased rice sensitivity to Na+, manifested by stunted plant growth, enhanced cellular damage, reduced PSII activity and changed chloroplast morphology. Mutation of OsNHAD also resulted in accumulation of more Na+ in chloroplasts and in shoots as well, suggesting that OsNHAD is involved in mediating efflux and detoxification of Na+ but does not affect K+ accumulation in plant cells. Complementation test reveals that OsNHAD was able to functionally restore the Arabidopsis mutant atnhd1-1 growth phenotype. These results suggest that OsNHAD possibly mediates homeostasis of sodium ions in the subcellular compartments and tissues of the plants when challenged to salt stress.