Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058 China.
Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058 China
Plant Physiol. 2020 Jan;182(1):584-596. doi: 10.1104/pp.19.00882. Epub 2019 Nov 5.
Maintaining low intracellular Na concentrations is an essential physiological strategy in salt stress tolerance in most cereal crops. Here, we characterized a member of the high-affinity K transporter (HKT) family in barley (), HvHKT1;5, which negatively regulates salt tolerance and has different functions from its homology in other cereal crops. ; encodes a plasma membrane protein localized to root stele cells, particularly in xylem parenchyma cells adjacent to the xylem vessels. Its expression was highly induced by salt stress. Heterogenous expression of ; in oocytes showed that HvHKT1;5 was permeable to Na, but not to K, although its Na transport activity was inhibited by external K ; knockdown barley lines showed improved salt tolerance, a dramatic decrease in Na translocation from roots to shoots, and increases in K/Na when compared with wild-type plants under salt stress. The negative regulation of HvHKT1;5 in salt tolerance distinguishes it from other HKT1;5 members, indicating that barley has a distinct Na transport system. These findings provide a deeper understanding of the functions of HKT family members and the regulation of ; in improving salt tolerance of barley.
维持低细胞内 Na 浓度是大多数谷类作物耐盐胁迫的一种重要生理策略。在这里，我们描述了大麦（）中高亲和力 K 转运体（HKT）家族的一个成员，HvHKT1;5，它负调控盐耐受性，并且与其他谷类作物中的同源物具有不同的功能。HvHKT1;5 编码一种定位于根中柱细胞的质膜蛋白，特别是在木质部薄壁细胞中与木质部导管相邻。其表达受盐胁迫强烈诱导。在卵母细胞中的异源表达表明 HvHKT1;5 对 Na 是可渗透的，但对 K 不可渗透，尽管其 Na 转运活性被外部 K 抑制；敲低大麦系在盐胁迫下表现出更好的耐盐性，从根部到地上部的 Na 转运显著减少，并且在 K/Na 方面与野生型植物相比有所增加。HvHKT1;5 在耐盐性中的负调控使其有别于其他 HKT1;5 成员，表明大麦具有独特的 Na 转运系统。这些发现为深入了解 HKT 家族成员的功能以及 HvHKT1;5 的调控在提高大麦耐盐性方面的作用提供了依据。
