Plant defense against heat stress involves adjustments in amino acid metabolism. The objective of this study was to identify major amino acids and associated metabolic pathways differentially regulated by γ-aminobutyric acid (GABA) and proline that may contribute to augmentation of heat tolerance in cool-season grass species. Creeping bentgrass (Agrostis stolonifera L. cv. ‘Penncross’) was exposed to non-stress (22/18 °C, day/night) or heat stress (35/30 °C, day/night) conditions for 35 d in controlled-environment growth chambers. Non-stressed and heat-stressed plants were foliar-sprayed with water (untreated control), GABA, proline, or ammonium nitrate (N) as a nitrogen source control. Under heat stress, foliar application of GABA, proline, or N significantly increased turf quality and leaf chlorophyll content compared to untreated control plants. N application had nutritional effects, resulting in increases in the content of all amino acids under heat stress. Application of GABA under heat stress significantly increased endogenous content of glutamic acid, GABA, and threonine. Plants treated with proline under heat stress had significantly higher endogenous levels of proline, GABA, glutamic acid, aspartic acid, lysine, isoleucine, leucine, valine, serine, alanine, threonine, and tryptophan compared to untreated controls. The improved heat tolerance in creeping bentgrass pathway by GABA was mainly associated with regulation of amino acid metabolism in the GABA shunt and oxaloacetate pathways. Proline-enhanced heat tolerance involved the regulation of five metabolic pathways (GABA shunt, oxaloacetate, 3-phosphoglycerate, secondary metabolism, and pyruvate). GABA and proline, as well as their responsive amino acids could be used as biomarkers to improve heat tolerance in cool-season grass species.

植物抗热胁迫涉及氨基酸代谢的调节。这项研究的目的是确定主要氨基酸和相关的代谢途径受γ-氨基丁酸（GABA）和脯氨酸的差异调节，这可能有助于增强凉季草​​种的耐热性。爬行本草（Agrostis stoloniferaL.简历 'Penncross'）在受控环境生长室中暴露于无压力（22/18°C，白天/夜晚）或热应激（35/30°C，白天/夜晚）条件下35 d。将未胁迫和热胁迫的植物叶片喷水（未经处理的对照），GABA，脯氨酸或硝酸铵（N）作为氮源对照。在热胁迫下，与未处理的对照植物相比，叶面施用GABA，脯氨酸或N显着提高了草皮质量和叶片叶绿素含量。施氮具有营养作用，导致热胁迫下所有氨基酸的含量增加。在热胁迫下施用GABA会显着增加谷氨酸，GABA和苏氨酸的内源性含量。在高温胁迫下用脯氨酸处理过的植物具有较高的内源性脯氨酸，GABA，谷氨酸，与未处理的对照组相比，天冬氨酸，赖氨酸，异亮氨酸，亮氨酸，缬氨酸，丝氨酸，丙氨酸，苏氨酸和色氨酸。GABA改善bent草的蠕动途径耐热性主要与调节GABA分流和草酰乙酸途径中的氨基酸代谢有关。脯氨酸增强的耐热性涉及五个代谢途径的调节（GABA分流，草酰乙酸，3-磷酸甘油酸，二次代谢和丙酮酸）。GABA和脯氨酸，以及它们的反应性氨基酸可以用作生物标记，以提高凉季草种的耐热性。GABA改善bent草的蠕动途径耐热性主要与调节GABA分流和草酰乙酸途径中的氨基酸代谢有关。脯氨酸增强的耐热性涉及五个代谢途径的调节（GABA分流，草酰乙酸，3-磷酸甘油酸，二次代谢和丙酮酸）。GABA和脯氨酸，以及它们的反应性氨基酸可以用作生物标记，以提高凉季草种的耐热性。GABA改善bent草的蠕动途径耐热性主要与调节GABA分流和草酰乙酸途径中的氨基酸代谢有关。脯氨酸增强的耐热性涉及五个代谢途径的调节（GABA分流，草酰乙酸，3-磷酸甘油酸，二次代谢和丙酮酸）。GABA和脯氨酸，以及它们的反应性氨基酸可以用作生物标记，以提高凉季草种的耐热性。