Nitric oxide (NO), γ‐aminobutyric acid (GABA), and mannose (MAS) could be important regulators of plant growth and adaptation to water stress. The application of sodium nitroprusside (SNP, a NO donor), GABA, and MAS improved plant growth under water‐sufficient conditions and effectively mitigated water stress damage to white clover. The metabonomic analysis showed that both SNP and GABA application resulted in a significant increase in myo‐inositol content; the accumulation of mannose was commonly regulated by SNP and MAS; GABA and MAS induced the accumulation of aspartic acid, quinic acid, trehalose, and glycerol under water deficit. In addition, citric acid was uniquely up‐regulated by SNP associated with tricarboxylic acid (TCA) cycle under water stress. GABA specially induced the accumulation of GABA, glycine, methionine, and aconitic acid related to GABA shunt, amino acids metabolism, and TCA cycle in response to water stress. MAS uniquely enhanced the accumulation of asparagine, galactose, and D‐pinitol in association with amino acids and sugars metabolism under water stress. SNP‐, GABA‐, and MAS‐induced changes of metabolic profiles and associated metabolic pathways could contribute to enhanced stress tolerance via involvement in the TCA cycle for energy supply, osmotic adjustment, antioxidant defense, and signal transduction for stress defense in white clover.

中文翻译：

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一氧化氮，γ-氨基丁酸和甘露糖预处理会影响水分胁迫下白三叶草的代谢特性。

一氧化氮（NO），γ-氨基丁酸（GABA）和甘露糖（MAS）可能是植物生长和适应水分胁迫的重要调节剂。硝普钠（SNP，NO供体），GABA和MAS的施用在节水条件下改善了植物生长，并有效减轻了水分胁迫对白三叶草的伤害。代谢组学分析表明，应用SNP和GABA均可导致肌醇含量显着增加。甘露糖的积累通常受SNP和MAS调控。在缺水的情况下，GABA和MAS诱导了天冬氨酸，奎宁酸，海藻糖和甘油的积累。此外，在水分胁迫下，柠檬酸被与三羧酸（TCA）循环有关的SNP独特地上调。GABA专门诱导GABA，甘氨酸，蛋氨酸，乌头酸与GABA分流，氨基酸代谢和TCA循环有关。MAS独特地增强了水分胁迫下天冬酰胺，半乳糖和D-松醇的积累以及氨基酸和糖的代谢。SNP，GABA和MAS诱导的代谢概况和相关代谢途径的变化可通过参与三叶草的三叶草能量供应，渗透调节，抗氧化防御和信号转导来增强抗逆性，从而增强白三叶草的抗逆性。