Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Plant Physiol Biochem. 2019 Dec;145:216-226. doi: 10.1016/j.plaphy.2019.10.018. Epub 2019 Nov 1.
γ-Aminobutyric acid (GABA), a non-proteinaceous amino acid, modulates plant growth and stress tolerance. However, the potential role of GABA in regulating key metabolic pathways and stress-defensive proteins against drought in plants has never been explored. Creeping bentgrass (Agrostis stolonifera) plants were pretreated with or without GABA and then subjected to water stress for 8 days in controlled growth chambers (23/19 °C, day/night). Physiological analysis showed that elevated endogenous GABA level via exogenous GABA application significantly mitigated water stress damage to creeping bentgrass, as manifested by increased leaf relative water content, water use efficiency, osmotic adjustment (OA), photochemical efficiency (Fv/Fm), net photosynthetic rate, and reduced oxidative damage. iTRAQ-based proteomics found that enhanced chaperones accumulation, carbohydrates, amino acids, and energy metabolism played important roles in protein protection, OA, energy maintenance, and metabolic balance, which is important adaptive response to drought stress in creeping bentgrass. The GABA further promoted energy production and conversion, antioxidant defense, and DHN3 accumulation that were essential for energy requirement, ROS-scavenging, and the prevention of cell dehydration in leaf during drought stress. In addition, GABA-treated plants maintained significantly higher abundance of dicarboxylate transporter 2.1, ATP-dependent zinc metalloprotease, receptor-like protein kinase HERK1, o-acyltransferase WSD1, omega-6 fatty acid desaturase, and two-component response regulator ORR21 than untreated plants under drought stress. The result provides new evidences that GABA-induced drought tolerance is possibly involved in the improvement of nitrogen recycling, protection of photosystem II, mitigation of drought-depressed cell elongation, wax biosynthesis, fatty acid desaturase, and delaying leaf senescence in creeping bentgrass.
γ-氨基丁酸（GABA）是一种非蛋白氨基酸，调节植物的生长和胁迫耐受性。然而，GABA 调节植物关键代谢途径和应激防御蛋白以应对干旱的潜在作用尚未被探索。先用或不用 GABA 预处理匍匐翦股颖（Agrostis stolonifera）植株，然后在控制生长室（23/19°C，白天/黑夜）中进行 8 天的水分胁迫。生理分析表明，通过外源 GABA 提高内源性 GABA 水平显著减轻了水分胁迫对匍匐翦股颖的伤害，表现为叶片相对含水量、水分利用效率、渗透调节（OA）、光化学效率（Fv/Fm）、净光合速率的增加和氧化损伤的降低。iTRAQ 蛋白质组学发现，增强的伴侣蛋白积累、碳水化合物、氨基酸和能量代谢在蛋白质保护、OA、能量维持和代谢平衡中发挥重要作用，这是匍匐翦股颖适应干旱胁迫的重要反应。GABA 进一步促进了能量的产生和转化、抗氧化防御和 DHN3 的积累，这对于干旱胁迫下叶片的能量需求、ROS 清除和细胞脱水的预防是必不可少的。此外，与未处理的植物相比，GABA 处理的植物在水分胁迫下保持了显著更高丰度的二羧酸转运蛋白 2.1、ATP 依赖性锌金属蛋白酶、类受体蛋白激酶 HERK1、酰基转移酶 WSD1、ω-6 脂肪酸去饱和酶和双组分响应调节剂 ORR21。结果提供了新的证据，表明 GABA 诱导的耐旱性可能涉及改善氮循环、保护光系统 II、减轻干旱抑制的细胞伸长、蜡生物合成、脂肪酸去饱和酶和延缓匍匐翦股颖叶片衰老。
