Key Laboratory of Plant Functional Genomics of the Ministry of Education / Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/ Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops/ Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, 225009, China.
Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, Prospect, TAS, 7250, Australia.
Theor Appl Genet. 2023 Jan;136(1):9. doi: 10.1007/s00122-023-04267-4. Epub 2023 Jan 19.
A major QTL (qS7.1) for salinity damage score and Na+ exclusion was identified on chromosome 7H from a barley population derived from a cross between a cultivated variety and a wild accession. qS7.1 was fine-mapped to a 2.46 Mb physical interval and HvNCX encoding a sodium/calcium exchanger is most likely the candidate gene. Soil salinity is one of the major abiotic stresses affecting crop yield. Developing salinity-tolerant varieties is critical for minimizing economic penalties caused by salinity and providing solutions for global food security. Many genes/QTL for salt tolerance have been reported in barley, but only a few of them have been cloned. In this study, a total of 163 doubled haploid lines from a cross between a cultivated barley variety Franklin and a wild barley accession TAM407227 were used to map QTL for salinity tolerance. Four significant QTL were identified for salinity damage scores. One (qS2.1) was located on 2H, determining 7.5% of the phenotypic variation. Two (qS5.1 and qS5.2) were located on 5H, determining 5.3-11.7% of the phenotypic variation. The most significant QTL was found on 7H, explaining 27.8% of the phenotypic variation. Two QTL for Na content in leaves under salinity stress were detected on chromosomes 1H (qNa1.1) and 7H(qNa7.1). qS7.1 was fine-mapped to a 2.46 Mb physical interval using F recombinant inbred lines. This region contains 23 high-confidence genes, with HvNCX which encodes a sodium/calcium exchanger being most likely the candidate gene. HvNCX was highly induced by salinity stress and showed a greater expression level in the sensitive parent. Multiple nucleotide substitutions and deletions/insertions in the promoter sequence of HvNCX were found between the two parents. cDNA sequencing of the HvNCX revealed that the difference between the two parents is conferred by a single Ala77/Pro77 amino acid substitution, which is located on the transmembrane domain. These findings open new prospects for improving salinity tolerance in barley by targeting a previously unexplored trait.
一个主要的 QTL（qS7.1）被鉴定为盐胁迫评分和 Na+排除的数量性状位点，位于一个由栽培品种和野生近缘种杂交衍生的大麦群体的 7H 染色体上。qS7.1 被精细定位到 2.46Mb 的物理区间内，HvNCX 编码一个钠/钙交换器，最有可能是候选基因。土壤盐度是影响作物产量的主要非生物胁迫之一。培育耐盐品种对于减轻盐胁迫造成的经济损失和为全球粮食安全提供解决方案至关重要。在大麦中已经报道了许多耐盐基因/QTL，但只有少数几个已经被克隆。在这项研究中，利用一个由栽培大麦品种 Franklin 和一个野生大麦近缘种 TAM407227 杂交衍生的 163 个加倍单倍体系，对耐盐性进行 QTL 作图。鉴定到 4 个显著的盐胁迫评分 QTL。一个（qS2.1）位于 2H，解释了 7.5%的表型变异。两个（qS5.1 和 qS5.2）位于 5H，解释了 5.3-11.7%的表型变异。最显著的 QTL 位于 7H，解释了 27.8%的表型变异。在染色体 1H（qNa1.1）和 7H（qNa7.1）上检测到 2 个叶片中 Na 含量在盐胁迫下的 QTL。qS7.1 使用 F2 重组自交系被精细定位到 2.46Mb 的物理区间内。该区域包含 23 个高可信度基因，其中 HvNCX 编码一个钠/钙交换器，最有可能是候选基因。HvNCX 受盐胁迫强烈诱导，在敏感亲本中表达水平更高。在两个亲本之间发现 HvNCX 启动子序列中存在多个核苷酸替换和缺失/插入。对 HvNCX 的 cDNA 测序表明，两个亲本之间的差异是由一个单一的 Ala77/Pro77 氨基酸替换引起的，该替换位于跨膜结构域上。这些发现为通过靶向一个以前未被探索的性状来提高大麦的耐盐性开辟了新的前景。
