State Key Laboratory of Plant Environmental Resilience, Frontiers Science Center for Molecular Design Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
J Integr Plant Biol. 2024 Apr;66(4):700-708. doi: 10.1111/jipb.13632. Epub 2024 Feb 26.
The high-affinity potassium transporters (HKTs), selectively permeable to either Na alone or Na/K, play pivotal roles in maintaining plant Na/K homeostasis. Although their involvement in salt tolerance is widely reported, the molecular underpinnings of Oryza sativa HKTs remain elusive. In this study, we elucidate the structures of OsHKT1;1 and OsHKT2;1, representing two distinct classes of rice HKTs. The dimeric assembled OsHKTs can be structurally divided into four domains. At the dimer interface, a half-helix or a loop in the third domain is coordinated by the C-terminal region of the opposite subunit. Additionally, we present the structures of OsHKT1;5 salt-tolerant and salt-sensitive variants, a key quantitative trait locus associated with salt tolerance. The salt-tolerant variant of OsHKT1;5 exhibits enhanced Na transport capability and displays a more flexible conformation. These findings shed light on the molecular basis of rice HKTs and provide insights into their role in salt tolerance.
高亲和力钾转运体（HKTs）对 Na 或 Na/K 具有选择性渗透性，在维持植物 Na/K 内稳态方面发挥着关键作用。尽管它们在耐盐性中的作用已被广泛报道，但水稻 HKTs 的分子基础仍不清楚。在这项研究中，我们阐明了代表两种不同水稻 HKT 类别的 OsHKT1;1 和 OsHKT2;1 的结构。二聚体组装的 OsHKTs 可以在结构上分为四个结构域。在二聚体界面上，第三个结构域中的半螺旋或环由相反亚基的 C 末端区域协调。此外，我们还展示了与耐盐性相关的关键数量性状位点 OsHKT1;5 耐盐和敏感变体的结构。OsHKT1;5 的耐盐变体表现出增强的 Na 转运能力，并呈现出更灵活的构象。这些发现为水稻 HKTs 的分子基础提供了线索，并深入了解了它们在耐盐性中的作用。
