Physiological, Biochemical, Epigenetic and Molecular Analyses of Wheat (Triticum aestivum) Genotypes with Contrasting Salt Tolerance.
Physiological, Biochemical, Epigenetic and Molecular Analyses of Wheat (Triticum aestivum) Genotypes with Contrasting Salt Tolerance.
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DOI：
10.3389/fpls.2017.01151
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发表时间：
2017
影响因子：
5.6
通讯作者：
Singh A
中科院分区：
文献类型：
--
作者：
Kumar S;Beena AS;Awana M;Singh A
非生物胁迫对植物的生长发育和生产力有着重要的影响。由于人们对植物耐盐的生理生化、表观遗传和分子机制的认识有限，盐胁迫下作物的生产力研究相对滞后。本研究旨在通过对小麦品种生理生化、分子生物学指标和盐胁迫防御反应的研究，筛选出盐胁迫反应差异最大的小麦品种，并探讨其盐胁迫反应差异的机制。生理生化性状，特别是膜稳定性指数，抗氧化能力，植物保护剂和叶绿素含量，在营养阶段测量，用于多变量分析，以确定最具对比的基因型。遗传和表观遗传分析揭示了盐胁迫下小麦基因型差异反应的可能机制。Kharchia-65具有更好的抗氧化潜力、膜稳定性、渗透调节物质/植物酚类物质积累增加以及200 mM NaCl胁迫下更高的K+/Na+比，因此是最耐盐的品种。而HD-2329的MDA含量增加，可溶性糖、脯氨酸、总叶绿素、总酚含量降低，抗氧化能力降低，表明其对胁迫敏感。遗传和生物信息学分析的HKT 1;4的对比基因型（Kharchia-65和HD-2329）显示缺失，转换，颠换导致结构改变，保守基序（Ser-Gly-Gly-Gly和Gly-Arg）的损失和盐敏感（HD-2329）基因型的功能。HKT的表达分析使观察到的反应合理化。胞嘧啶甲基化的表观遗传变异解释了HKT 2;1和HKT 2;3的组织和基因型特异性差异表达。
Abiotic stress exerts significant impact on plant’s growth, development, and productivity. Productivity of crop plants under salt stress is lagging behind because of our limited knowledge about physiological, biochemical, epigenetic, and molecular mechanisms of salt tolerance in plants. This study aimed to investigate physio-biochemical, molecular indices and defense responses of selected wheat cultivars to identify the most contrasting salt-responsive genotypes and the mechanisms associated with their differential responses. Physio-biochemical traits specifically membrane stability index, antioxidant potential, osmoprotectants and chlorophyll contents, measured at vegetative stage, were used for multivariate analysis to identify the most contrasting genotypes. Genetic and epigenetic analyses indicated the possible mechanisms associated with differential response of the wheat genotypes under salt stress. Better antioxidant potential, membrane stability, increased accumulation of osmolytes/phytophenolics, and higher K+/Na+ ratio under 200 mM NaCl stress identified Kharchia-65 to be the most salt-tolerant cultivar. By contrast, increased MDA level, reduced soluble sugar, proline, total chlorophyll, total phenolics contents, and lower antioxidant potential in HD-2329 marked it to be sensitive to the stress. Genetic and bioinformatics analyses of HKT1;4 of contrasting genotypes (Kharchia-65 and HD-2329) revealed deletions, transitions, and transversions resulting into altered structure, loss of conserved motifs (Ser-Gly-Gly-Gly and Gly-Arg) and function in salt-sensitive (HD-2329) genotype. Expression analysis of HKTs rationalized the observed responses. Epigenetic variations in cytosine methylation explained tissue- and genotype-specific differential expression of HKT2;1 and HKT2;3.