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A Sodium Transporter HvHKT1;1 Confers Salt Tolerance in Barley via Regulating Tissue and Cell Ion Homeostasis.
- Source :
- Plant & Cell Physiology; Oct2018, Vol. 59 Issue 10, p1976-1989, 14p
- Publication Year :
- 2018
-
Abstract
- Our previous studies showed that high salt tolerance in Tibetan wild barley accessions was associated with HvHKT1;1, a member of the high-affinity potassium transporter family. However, molecular mechanisms of HvHKT1;1 for salt tolerance and its roles in K<superscript>+</superscript>/Na<superscript>+</superscript> homeostasis remain to be elucidated. Functional characterization of HvHKT1;1 was conducted in the present study. NaCl-induced transcripts of HvHKT1;1 were significantly higher in the roots of Tibetan wild barley XZ16 relative to other genotypes, being closely associated with its higher biomass and lower tissue Na<superscript>+</superscript> content under salt stress. Heterologous expression of HvHKT1;1 in Saccharomyces cerevisiae (yeast) and Xenopus laevis oocytes showed that HvHKT1;1 had higher selectivity for Na<superscript>+</superscript> over K<superscript>+</superscript> and other monovalent cations. HvHKT1;1 was found to be localized at the cell plasma membrane of root stele and epidermis. Knock-down of HvHKT1;1 in barley led to higher Na<superscript>+</superscript> accumulation in both roots and leaves, while overexpression of HvHKT1;1 in salt-sensitive Arabidopsis hkt1-4 and sos1-12 loss-of-function lines resulted in significantly less shoot and root Na<superscript>+</superscript> accumulation. Additionally, microelectrode ion flux measurements and root elongation assay revealed that the transgenic Arabidopsis plants exhibited a remarkable capacity for regulation of Na<superscript>+</superscript>, K<superscript>+</superscript>, Ca<superscript>2+</superscript> and H<superscript>+</superscript> homeostasis under salt stress. These results indicate that HvHKT1;1 is critical in radial root Na<superscript>+</superscript> transport, which eventually reduces shoot Na<superscript>+</superscript> accumulation. Additionally, HvHKT1;1 may be indirectly involved in retention of K<superscript>+</superscript> and Ca<superscript>2+</superscript> in root cells, which also improves plant salt tolerance. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00320781
- Volume :
- 59
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- Plant & Cell Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 132317031
- Full Text :
- https://doi.org/10.1093/pcp/pcy116