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

Yakupjan Haxim; Lei Wang; Zhendong Pan; Xiaorong Fan; Jinbiao Ma

doi:10.3389/fpls.2023.1104070

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

Front Plant Sci. 2023 Feb 20:14:1104070. doi: 10.3389/fpls.2023.1104070. eCollection 2023.

Authors

Yakupjan Haxim^{1

2

3}, Lei Wang¹, Zhendong Pan^{1

3}, Xiaorong Fan⁴, Jinbiao Ma^{1

2

3}

Affiliations

¹ State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China.
² Xinjiang Key Laboratory of Conservation and Utilization of Plant Gene Resources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China.
³ Turpan Eremophytes Botanical Garden, Chinese Academy of Sciences, Turpan, China.
⁴ State Key Laboratory of Crop Genetics and Germplasm Enhancement, MOA Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China.

Abstract

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 SeHKT1;2 was isolated and characterized from the halophyte, Salicornia europaea. It belongs to subfamily I of HKT and shows high homology with other halophyte HKT proteins. Functional characterization of SeHKT1;2 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 SeHKT1;2 in sos1 mutant of Arabidopsis thaliana 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.

Keywords: HKT; Salicornia europaea; high-affinity K+ transporters; ion selectivity; salt tolerance.

Grants and funding

This work was funded by the Xinjiang Uygur Autonomous Region regional coordinated innovation project (Shanghai cooperation organization science and technology partnership program) (No. 2022E01022), Introduction Project of High-level Talents in Xinjiang Uygur Autonomous Region.