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Plant function and evolutionary biology
RESEARCH ARTICLE

SsHKT1;1 is a potassium transporter of the C3 halophyte Suaeda salsa that is involved in salt tolerance

Qun Shao A , Ning Han A C , Tonglou Ding A , Feng Zhou A C and Baoshan Wang A D
+ Author Affiliations
- Author Affiliations

A Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Jinan 250 014, China.

B Present address: Key Laboratory of Biotechnology, College of Food and Biologic Engineering, Qi Lu University of Technology, Jinan 250 353, China.

C Present address: School of Biochemical and Environmental Engineering, Nanjing Xiaozhuang University, Nanjing 211 171, China.

D Corresponding author. Email: bswang@sdnu.edu.cn

Functional Plant Biology 41(8) 790-802 https://doi.org/10.1071/FP13265
Submitted: 5 September 2013  Accepted: 28 January 2014   Published: 28 April 2014

Abstract

SsHKT1;1, a HKT1 homologue, was isolated from the C3 halophyte Suaeda salsa L. and its ion transport properties were investigated in heterologous systems. The expression of SsHKT1;1 suppressed a K+ transport-defective phenotype of the yeast strain CY162 (Δtrk1Δtrk2), suggesting the enhancement of K+ uptake with SsHKT1;1. However, it did not suppress the salt-sensitive phenotype of the yeast strain G19 (Δena14), which lacks a major component of Na+ efflux. Transgenic Arabidopsis thaliana (L.) Heynh. plants overexpressing SsHKT1;1 showed enhanced salt tolerance and increased shoot K+ concentration, whereas no significant changes in shoot Na+ concentration were observed. S. salsa was also used to investigate K+ uptake properties under salinity. The K+ transporters in the roots selectively mediated K+ uptake irrespective of external Na+ and their inhibitor did not affect Na+ uptake at low K+. Thus, both molecular and physiological studies provide strong in vivo evidence that SsHKT1;1 mainly acts as a potassium transporter in heterologous expression systems and S. salsa, and that it is involved in salt tolerance by taking part in the maintenance of cytosolic cation homeostasis, particularly, in the maintenance of K+ nutrition under salinity.

Additional keywords: euhalophyte, heterologous systems, ion transport properties.


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