Abstract Soil salinity is a major abiotic stressor and a serious threat to global food security. Biochemical compounds synthesised by plants ameliorate the effects of such stressors in characteristic ways. It is crucial to unravel the key components of the salt tolerance network to engineer salt-tolerant genotypes of crops. For the elucidation of the metabolic contribution to salinity response (long-term stress under 100 mM NaCl) in selected cultivars, we used a gas chromatography mass spectrometry approach. The metabolic profiling of grains yielded sixty-five metabolites. By comparing a salt-sensitive cultivar of barley (Scope) to a salt-tolerant one (GrangeR), we identified six and twenty significant metabolites in salt-stressed seeds of Scope and GrangeR, respectively. These included amino acids, sugars, sugar derivatives and organic acids. Whilst the concentrations of fructose reduced, glycine, glucitol and urea accumulated under salt stress in both varieties. Amino acids such as phenylalanine, tryptophan and tyrosine, sugar acids such as galactaric acid and glucuronic acid, and several other key metabolites accumulated in GrangeR only. These metabolites are relevant to metabolic pathways of amino acid metabolism, energy metabolism, carbohydrate metabolism, glycolysis, gluconeogenesis, pyruvate metabolism, shikimate pathway, TCA cycle, inositol phosphate metabolism and galactose metabolism. Hence these compounds could be potentially used as biomarkers of abiotic stress responses and effects on grain quality and yield parameters. This work provides greater insights into functional metabolism in response to salinity stress and may help to dissect patterns associated with salt responses. Metabolites identified in this work could serve as accurate markers for salt-tolerant crop selection in breeding programs.

中文翻译：

---

两种具有不同耐盐性的大麦品种对盐胁迫响应的代谢贡献

摘要 土壤盐分是主要的非生物压力源，严重威胁全球粮食安全。植物合成的生化化合物以特有的方式改善了这些压力源的影响。解开耐盐网络的关键组成部分对设计作物耐盐基因型至关重要。为了阐明选定品种对盐度响应（100 mM NaCl 下的长期胁迫）的代谢贡献，我们使用了气相色谱质谱法。谷物的代谢分析产生了 65 种代谢物。通过将盐敏感的大麦品种 (Scope) 与耐盐品种 (GrangeR) 进行比较，我们分别在 Scope 和 GrangeR 的盐胁迫种子中鉴定了 6 种和 20 种重要代谢物。这些包括氨基酸、糖、糖衍生物和有机酸。虽然果糖浓度降低，但两个品种的甘氨酸、葡萄糖醇和尿素在盐胁迫下积累。苯丙氨酸、色氨酸和酪氨酸等氨基酸，半乳糖酸和葡萄糖醛酸等糖酸，以及仅在 GrangeR 中积累的其他几种关键代谢物。这些代谢物与氨基酸代谢、能量代谢、碳水化合物代谢、糖酵解、糖异生、丙酮酸代谢、莽草酸途径、三羧酸循环、磷酸肌醇代谢和半乳糖代谢等代谢途径有关。因此，这些化合物可能被用作非生物胁迫反应和对谷物质量和产量参数影响的生物标志物。这项工作提供了对盐分胁迫反应的功能代谢的更深入的了解，并可能有助于剖析与盐分反应相关的模式。在这项工作中鉴定的代谢物可以作为育种计划中耐盐作物选择的准确标记。