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Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism
Sodium (Na(+)) accumulation in the cytosol will result in ion homeostasis imbalance and toxicity of transpiring leaves. Studies of salinity tolerance in the diploid wheat ancestor Triticum monococcum showed that HKT1;5-like gene was a major gene in the QTL for salt tolerance, named Nax2. In the pres...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5826053/ https://www.ncbi.nlm.nih.gov/pubmed/29515598 http://dx.doi.org/10.3389/fpls.2018.00156 |
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author | Hazzouri, Khaled M. Khraiwesh, Basel Amiri, Khaled M. A. Pauli, Duke Blake, Tom Shahid, Mohammad Mullath, Sangeeta K. Nelson, David Mansour, Alain L. Salehi-Ashtiani, Kourosh Purugganan, Michael Masmoudi, Khaled |
author_facet | Hazzouri, Khaled M. Khraiwesh, Basel Amiri, Khaled M. A. Pauli, Duke Blake, Tom Shahid, Mohammad Mullath, Sangeeta K. Nelson, David Mansour, Alain L. Salehi-Ashtiani, Kourosh Purugganan, Michael Masmoudi, Khaled |
author_sort | Hazzouri, Khaled M. |
collection | PubMed |
description | Sodium (Na(+)) accumulation in the cytosol will result in ion homeostasis imbalance and toxicity of transpiring leaves. Studies of salinity tolerance in the diploid wheat ancestor Triticum monococcum showed that HKT1;5-like gene was a major gene in the QTL for salt tolerance, named Nax2. In the present study, we were interested in investigating the molecular mechanisms underpinning the role of the HKT1;5 gene in salt tolerance in barley (Hordeum vulgare). A USDA mini-core collection of 2,671 barley lines, part of a field trial was screened for salinity tolerance, and a Genome Wide Association Study (GWAS) was performed. Our results showed important SNPs that are correlated with salt tolerance that mapped to a region where HKT1;5 ion transporter located on chromosome four. Furthermore, sodium (Na(+)) and potassium (K(+)) content analysis revealed that tolerant lines accumulate more sodium in roots and leaf sheaths, than in the sensitive ones. In contrast, sodium concentration was reduced in leaf blades of the tolerant lines under salt stress. In the absence of NaCl, the concentration of Na(+) and K(+) were the same in the roots, leaf sheaths and leaf blades between the tolerant and the sensitive lines. In order to study the molecular mechanism behind that, alleles of the HKT1;5 gene from five tolerant and five sensitive barley lines were cloned and sequenced. Sequence analysis did not show the presence of any polymorphism that distinguishes between the tolerant and sensitive alleles. Our real-time RT-PCR experiments, showed that the expression of HKT1;5 gene in roots of the tolerant line was significantly induced after challenging the plants with salt stress. In contrast, in leaf sheaths the expression was decreased after salt treatment. In sensitive lines, there was no difference in the expression of HKT1;5 gene in leaf sheath under control and saline conditions, while a slight increase in the expression was observed in roots after salt treatment. These results provide stronger evidence that HKT1;5 gene in barley play a key role in withdrawing Na(+) from the xylem and therefore reducing its transport to leaves. Given all that, these data support the hypothesis that HKT1;5 gene is responsible for Na(+) unloading to the xylem and controlling its distribution in the shoots, which provide new insight into the understanding of this QTL for salinity tolerance in barley. |
format | Online Article Text |
id | pubmed-5826053 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-58260532018-03-07 Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism Hazzouri, Khaled M. Khraiwesh, Basel Amiri, Khaled M. A. Pauli, Duke Blake, Tom Shahid, Mohammad Mullath, Sangeeta K. Nelson, David Mansour, Alain L. Salehi-Ashtiani, Kourosh Purugganan, Michael Masmoudi, Khaled Front Plant Sci Plant Science Sodium (Na(+)) accumulation in the cytosol will result in ion homeostasis imbalance and toxicity of transpiring leaves. Studies of salinity tolerance in the diploid wheat ancestor Triticum monococcum showed that HKT1;5-like gene was a major gene in the QTL for salt tolerance, named Nax2. In the present study, we were interested in investigating the molecular mechanisms underpinning the role of the HKT1;5 gene in salt tolerance in barley (Hordeum vulgare). A USDA mini-core collection of 2,671 barley lines, part of a field trial was screened for salinity tolerance, and a Genome Wide Association Study (GWAS) was performed. Our results showed important SNPs that are correlated with salt tolerance that mapped to a region where HKT1;5 ion transporter located on chromosome four. Furthermore, sodium (Na(+)) and potassium (K(+)) content analysis revealed that tolerant lines accumulate more sodium in roots and leaf sheaths, than in the sensitive ones. In contrast, sodium concentration was reduced in leaf blades of the tolerant lines under salt stress. In the absence of NaCl, the concentration of Na(+) and K(+) were the same in the roots, leaf sheaths and leaf blades between the tolerant and the sensitive lines. In order to study the molecular mechanism behind that, alleles of the HKT1;5 gene from five tolerant and five sensitive barley lines were cloned and sequenced. Sequence analysis did not show the presence of any polymorphism that distinguishes between the tolerant and sensitive alleles. Our real-time RT-PCR experiments, showed that the expression of HKT1;5 gene in roots of the tolerant line was significantly induced after challenging the plants with salt stress. In contrast, in leaf sheaths the expression was decreased after salt treatment. In sensitive lines, there was no difference in the expression of HKT1;5 gene in leaf sheath under control and saline conditions, while a slight increase in the expression was observed in roots after salt treatment. These results provide stronger evidence that HKT1;5 gene in barley play a key role in withdrawing Na(+) from the xylem and therefore reducing its transport to leaves. Given all that, these data support the hypothesis that HKT1;5 gene is responsible for Na(+) unloading to the xylem and controlling its distribution in the shoots, which provide new insight into the understanding of this QTL for salinity tolerance in barley. Frontiers Media S.A. 2018-02-19 /pmc/articles/PMC5826053/ /pubmed/29515598 http://dx.doi.org/10.3389/fpls.2018.00156 Text en Copyright © 2018 Hazzouri, Khraiwesh, Amiri, Pauli, Blake, Shahid, Mullath, Nelson, Mansour, Salehi-Ashtiani, Purugganan and Masmoudi. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Plant Science Hazzouri, Khaled M. Khraiwesh, Basel Amiri, Khaled M. A. Pauli, Duke Blake, Tom Shahid, Mohammad Mullath, Sangeeta K. Nelson, David Mansour, Alain L. Salehi-Ashtiani, Kourosh Purugganan, Michael Masmoudi, Khaled Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title | Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title_full | Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title_fullStr | Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title_full_unstemmed | Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title_short | Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism |
title_sort | mapping of hkt1;5 gene in barley using gwas approach and its implication in salt tolerance mechanism |
topic | Plant Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5826053/ https://www.ncbi.nlm.nih.gov/pubmed/29515598 http://dx.doi.org/10.3389/fpls.2018.00156 |
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