Structural insights into the <i>Oryza sativa</i> cation transporters HKTs in salt tolerance
R. X. Gao, Yutian Jia, Xia Xu, Peng Fu, Jiaqi Zhou, Guanghui Yang
Abstract
ABSTRACT 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.