A novel high-affinity potassium transporter SeHKT1;2 from halophyte shows strong selectivity for Na rather than K.

High-affinity K transporters (HKTs) are known as transmembrane cation transporters and are involved in Na or Na-K transport in plants. In this study, a novel HKT gene was isolated and characterized from the halophyte, . It belongs to subfamily I of HKT and shows high homology with other halophyte HKT proteins. Functional characterization of indicated that it contributes to facilitating Na uptake in Na-sensitive yeast strains G19, however, cannot rescue the K uptake-defective phenotype of yeast strain CY162, demonstrating SeHKT1;2 selectively transports Na rather than K. The addition of K along with NaCl relieved the Na sensitivity. Furthermore, heterologous expression of in mutant of increased salt sensitivity and could not rescued the transgenic plants. This study will provide valuable gene resources for improving the salt tolerance in other crops by genetic engineering.