INRES-Pflanzenzuchtung, Rheinische Friedrich-Wilhelms-Universitat, Bonn, Germany.
Center for Development Research (ZEF), Rheinische Friedrich-Wilhelms-Universitat, Bonn, Germany.
Theor Appl Genet. 2019 Feb;132(2):323-346. doi: 10.1007/s00122-018-3220-5. Epub 2018 Nov 3.
SNP alleles on chromosomes 4BL and 6AL are associated with sensitivity to salt tolerance in wheat and upon validation can be exploited in the development of salt-tolerant wheat varieties. The dissection of the genetic and molecular components of salt stress response offers strong opportunities toward understanding and improving salt tolerance in crops. In this study, GWAS was employed to identify a total of 106 SNP loci (R = 0.12-63.44%) linked to salt stress response in wheat using leaf chlorophyll fluorescence, grain quality and shoot ionic (Na and K ions) attributes. Among them, 14 SNP loci individually conferred pleiotropic effects on multiple independent salinity tolerance traits including loci at 99.04 cM (R ≥ 14.7%) and 68.45 cM (R ≥ 4.10%) on chromosomes 6AL and 4BL, respectively, that influenced shoot Na-uptake, shoot K/Na ratio, and specific energy fluxes for absorption (ABS/RC) and dissipation (DIo/RC). Analysis of the open reading frame (ORF) containing the SNP markers revealed that they are orthologous to genes involved in photosynthesis and plant stress (salt) response. Further transcript abundance and qRT-PCR analyses indicated that the genes are mostly up-regulated in salt-tolerant and down-regulated in salt-sensitive wheat genotypes including NRAMP-2 and OPAQUE1 genes on 4BL and 6AL, respectively. Both genes showed highest differential expression between contrasting genotypes when expressions of all the genes within their genetic intervals were analyzed. Possible cis-acting regulatory elements and coding sequence variation that may be involved in salt stress response were also identified in both genes. This study identified genetic and molecular components of salt stress response that are associated with Na-uptake, shoot Na/K ratio, ABS/RC, DIo/RC, and grain quality traits and upon functional validation would facilitate the development of gene-specific markers that could be deployed to improve salinity tolerance in wheat.
SNP 等位基因位于染色体 4BL 和 6AL 上，与小麦的耐盐性敏感有关，经过验证后可用于开发耐盐小麦品种。对盐胁迫响应的遗传和分子组成的剖析为理解和提高作物的耐盐性提供了很好的机会。在这项研究中，利用叶片叶绿素荧光、籽粒品质和地上部离子（Na 和 K 离子）特性，通过全基因组关联分析（GWAS）共鉴定出 106 个与小麦盐胁迫响应相关的 SNP 位点（R=0.12-63.44%）。其中，位于染色体 6AL 和 4BL 上的 99.04cM（R≥14.7%）和 68.45cM 处的 14 个 SNP 位点分别对多个独立的耐盐性性状具有多效性效应，包括影响地上部 Na 吸收、地上部 K/Na 比以及吸收（ABS/RC）和耗散（DIo/RC）的特定能量通量的位点。对包含 SNP 标记的开放阅读框（ORF）的分析表明，它们与光合作用和植物应激（盐）反应相关基因同源。进一步的转录丰度和 qRT-PCR 分析表明，这些基因在耐盐和盐敏感小麦基因型中大多上调，包括 4BL 和 6AL 上的 NRAMP-2 和 OPAQUE1 基因。当分析它们遗传区间内所有基因的表达时，这两个基因在对照基因型之间表现出最高的差异表达。在这两个基因中还鉴定到可能与盐胁迫反应相关的顺式作用调控元件和编码序列变异。本研究鉴定了与 Na 吸收、地上部 Na/K 比、ABS/RC、DIo/RC 和籽粒品质性状相关的盐胁迫响应的遗传和分子组成，经过功能验证后，将有助于开发特定基因的标记，可用于提高小麦的耐盐性。
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