The potassium transporter OsHAK21 functions in the maintenance of ion homeostasis and tolerance to salt stress in rice
The potassium transporter OsHAK21 functions in the maintenance of ion homeostasis and tolerance to salt stress in rice
复制标题
钾转运蛋白 OsHAK21 在维持水稻离子稳态和耐盐胁迫中发挥作用
DOI：
10.1111/pce.12586
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发表时间：
2015-12-01
影响因子：
7.3
通讯作者：
Zhang, Wenhua
中科院分区：
文献类型：
--
作者：
Shen, Yue;Shen, Like;Zhang, Wenhua
细胞内钾(K+)的稳态是植物在盐碱环境中生存的关键，它受K+通道和转运蛋白的调节。高亲和力K+转运体(HAK)家族中的一些成员被认为在植物耐盐性的调节中发挥作用，但其生理机制尚不清楚。在这里，我们报道了高盐处理对OsHAK21表达的显著诱导，并提供了OsHAK21参与水稻耐盐性的遗传证据。OsHAK21基因的中断使植物对盐胁迫敏感。与野生型相比，oshak21在地上部和根部积累的K+较少，而积累的Na+较多，K+净吸收速率显著低于野生型，而Na+吸收速率显著高于野生型。我们的亚细胞定位和表达模式分析表明，OsHAK21定位于细胞膜，在木质部薄壁组织和单个内胚层细胞(可能的传代细胞)中表达。进一步对OsHAK21在K+吸收不足的酵母和拟南芥中的功能特性进行了研究，结果表明OsHAK21具有K+转运蛋白活性。这些结果表明，OsHAK21可能介导了质膜对K+的吸收，在维持盐胁迫下水稻体内Na+/K+动态平衡方面发挥了重要作用。
The intracellular potassium (K+) homeostasis, which is crucial for plant survival in saline environments, is modulated by K+ channels and transporters. Some members of the high-affinity K+ transporter (HAK) family are believed to function in the regulation of plant salt tolerance, but the physiological mechanisms remain unclear. Here, we report a significant inducement of OsHAK21 expression by high-salinity treatment and provide genetic evidence of the involvement of OsHAK21 in rice salt tolerance. Disruption of OsHAK21 rendered plants sensitive to salt stress. Compared with the wild type, oshak21 accumulated less K+ and considerably more Na+ in both shoots and roots, and had a significantly lower K+ net uptake rate but higher Na+ uptake rate. Our analyses of subcellular localizations and expression patterns showed that OsHAK21 was localized in the plasma membrane and expressed in xylem parenchyma and individual endodermal cells (putative passage cells). Further functional characterizations of OsHAK21 in K+ uptake-deficient yeast and Arabidopsis revealed that OsHAK21 possesses K+ transporter activity. These results demonstrate that OsHAK21 may mediate K+ absorption by the plasma membrane and play crucial roles in the maintenance of the Na+/K+ homeostasis in rice under salt stress.