Accumulation of specific metabolites, mainly γ-aminobutyric acid, polyamines, and proline, was essential to homeostasis regulation and differential salt tolerance in sorghum genotypes. Salinity is severe abiotic stress that limits plant growth and development in arid and semi-arid regions. Survival to abiotic stresses depends on metabolic and sometimes even morphological adjustments. We measured the growth parameters, water relations, the content of ions (Na+, K+, Cl–), compatible solutes [some free amino acids (FAAs) including γ-aminobutyric acid (GABA) and proline and soluble carbohydrates) and polyamines (PAs), the activity of PAs metabolism enzymes, and metabolomic profile in plants after 14 days of salt stress treatment. These analyses were to evaluate the influence of metabolomic responses of sorghum genotypes exhibiting sensitivity (CSF18) or tolerance (CSF20) to salinity on plant growth. The salinity promoted growth reductions and induced increases in Na+ and Cl– content and decreases in K+ content. The water status and osmotic potential (Ψo) were reduced by salt stress, but to minimize damage, especially in the CSF20, the osmolytes and PAs contributed to the osmotic adjustment. The results showed that salinity induced an increase in putrescine (Put) in the sensitive genotype. However, it raised spermidine (Spd), spermine (Spm), and cadaverine (Cad) in the tolerant genotype. In addition, the regulation of polyamine oxidase can be related to Spm and GABA biosynthesis. Differential metabolic changes to salt tolerance include metabolites associated with tricarboxylic acid (TCA) cycle intermediates and the metabolisms of sugars, FAAs, and PAs.

中文翻译：

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与高粱基因型不同耐盐性相关的代谢变化

特定代谢物的积累，主要是 γ-氨基丁酸、多胺和脯氨酸，对高粱基因型的稳态调节和不同的耐盐性至关重要。盐度是限制干旱和半干旱地区植物生长发育的严重非生物胁迫。非生物胁迫的生存取决于代谢，有时甚至是形态调整。我们测量了生长参数、水分关系、离子含量（Na+、K+、Cl-）、相容溶质 [一些游离氨基酸 (FAA)，包括 γ-氨基丁酸 (GABA) 和脯氨酸和可溶性碳水化合物) 和多胺 (PA )、盐胁迫处理 14 天后植物中 PAs 代谢酶的活性和代谢组学特征。这些分析旨在评估对盐度表现出敏感性（CSF18）或耐受性（CSF20）的高粱基因型的代谢组学反应对植物生长的影响。盐度促进了生长减少，导致 Na+ 和 Cl- 含量增加，K+ 含量降低。盐胁迫降低了水状态和渗透势 (Ψo)，但为了最大限度地减少损害，特别是在 CSF20 中，渗透物和 PA 有助于渗透调节。结果表明，盐度诱导敏感基因型中腐胺（Put）的增加。然而，它在耐受基因型中提高了亚精胺 (Spd)、精胺 (Spm) 和尸胺 (Cad)。此外，多胺氧化酶的调节可能与Spm和GABA的生物合成有关。