The HKT transporter HvHKT1;5 negatively regulates salt tolerance

Huang, L., Kuang, L., Wu, L., Shen, Q., Han, Y.ORCID: 0000-0001-6480-0398, Jiang, L., Wu, D. and Zhang, G. (2019) The HKT transporter HvHKT1;5 negatively regulates salt tolerance. Plant Physiology, 182 (1). pp. 584-596.

Abstract

Maintaining low intracellular Na+ concentrations is an essential physiological strategy in salt stress tolerance in most cereal crops. Here, we characterized a member of the high-affinity K+ transporter (HKT) family in barley (Hordeum vulgare), HvHKT1;5, which negatively regulates salt tolerance and has different functions from its homology in other cereal crops. HvHKT1;5 encodes a plasma membrane protein localized to root stele cells, particularly in xylem parenchyma cells adjacent to the xylem vessels. Its expression was highly induced by salt stress. Heterogenous expression of HvHKT1;5 in Xenopus laevis oocytes showed that HvHKT1;5 was permeable to Na+, but not to K+, although its Na+ transport activity was inhibited by external K+. HvHKT1;5 knockdown barley lines showed improved salt tolerance, a dramatic decrease in Na+ translocation from roots to shoots, and increases in K+/Na+ when compared with wild-type plants under salt stress. The negative regulation of HvHKT1;5 in salt tolerance distinguishes it from other HKT1;5 members, indicating that barley has a distinct Na+ transport system. These findings provide a deeper understanding of the functions of HKT family members and the regulation of HvHKT1;5 in improving salt tolerance of barley.

Item Type:	Journal Article
Copyright:	© 2020 American Society of Plant Biologists
URI:	http://researchrepository.murdoch.edu.au/id/eprint/54940

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