γ-Aminobutyric acid (GABA) acts as an important regulator involved in the mediation of cell signal transduction and stress tolerance in plants. However, the function of GABA in transcriptional regulation is not fully understood in plants under water stress. The creeping bentgrass (Agrostis stolonifera) was pretreated with or without GABA (0.5 mM) for 24 hours before being exposed to 5 days of water stress. Physiological analysis showed that GABA-treated plants maintained significantly higher endogenous GABA content, leaf relative water content, net photosynthetic rate, and lower osmotic potential than untreated plants under water stress. The GABA application also significantly alleviated stress-induced increases in superoxide anion (O2 .-) content, hydrogen peroxide (H2O2) content, and electrolyte leakage through enhancing total antioxidant capacity, superoxide dismutase (SOD) activity, and peroxidase (POD) activity in response to water stress. The transcriptomic analysis demonstrated that the GABA-induced changes in differentially expressed genes (DEGs) involved in carbohydrates, amino acids, and secondary metabolism helped to maintain better osmotic adjustment, energy supply, and metabolic homeostasis when creeping bentgrass suffers from water stress. The GABA triggered Ca2+-dependent protein kinase (CDPK) signaling and improved transcript levels of DREB1/2 and WRKY1/24/41 that could be associated with the upregulation of stress-related functional genes such as POD, DHNs, and HSP70 largely contributing to improved tolerance to water stress in relation to the antioxidant, prevention of cell dehydration, and protein protection in leaves.

中文翻译：

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γ-氨基丁酸诱导的转录调控和逆境防御关键基因与匍匐翦股颖耐水胁迫的关系

γ-氨基丁酸（GABA）是参与介导植物细胞信号转导和胁迫耐受性的重要调节剂。然而，在水分胁迫下的植物中，GABA 在转录调控中的功能尚不完全清楚。匍匐翦股颖 (Agrostis stolonifera) 在暴露于 5 天的水分胁迫之前，用或不用 GABA (0.5 mM) 预处理 24 小时。生理分析表明，在水分胁迫下，GABA处理的植物比未处理的植物保持显着较高的内源GABA含量、叶片相对含水量、净光合速率和较低的渗透势。GABA 的应用还通过增强总抗氧化能力、超氧化物歧化酶 (SOD) 活性和过氧化物酶 (POD) 活性，显着减轻了应激引起的超氧阴离子 (O2.-) 含量、过氧化氢 (H2O2) 含量和电解质渗漏的增加。对水分胁迫的反应。转录组分析表明，当匍匐翦股颖遭受水分胁迫时，GABA诱导的涉及碳水化合物、氨基酸和次生代谢的差异表达基因（DEG）的变化有助于维持更好的渗透调节、能量供应和代谢稳态。GABA 触发 Ca2+ 依赖性蛋白激酶 (CDPK) 信号传导并提高 DREB1/2 和 WRKY1/24/41 的转录水平，这可能与应激相关功能基因（如 POD、DNH 和 HSP70）的上调有关，这在很大程度上有助于提高与抗氧化剂、防止细胞脱水和叶子蛋白质保护有关的水胁迫耐受性。