Metabolomics and physiological analyses reveal β-sitosterol as an important plant growth regulator inducing tolerance to water stress in white clover
Metabolomics and physiological analyses reveal β-sitosterol as an important plant growth regulator inducing tolerance to water stress in white clover
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DOI：
10.1007/s00425-019-03277-1
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发表时间：
2019-12-01
期刊：
影响因子：
4.3
通讯作者：
Nie, Gang
中科院分区：
文献类型：
--
作者：
Li, Zhou;Cheng, Bizhen;Nie, Gang
主要结论β-谷甾醇影响白三叶体内氨基酸、碳水化合物、有机酸等代谢产物的代谢和动态平衡，有助于提高白三叶对水分胁迫的耐受性。当植物受到恶劣环境条件的影响时，β-谷甾醇(BS)可以作为一种重要的植物生长调节剂。本研究旨在从生理反应和代谢组学角度研究BS对白三叶生长和水分胁迫耐受性的影响。对白三叶进行加或不加BS的处理，然后在控制生长室内进行7d的水分胁迫。生理分析表明，外源BS(120亩M)能显著提高白三叶的耐逆性，表现出较好的生长性能和光合作用，叶片相对含水量较高，对水分胁迫的氧化损伤较小。代谢谱鉴定出白三叶叶片中涉及氨基酸、有机酸、糖、糖醇和其他代谢物的78种核心代谢物。在糖和糖醇代谢方面，BS处理促进了水分胁迫下白三叶果糖、葡萄糖、麦芽糖和肌醇的积累，有助于提高白三叶的抗氧化能力、维持生长和渗透调节。BS处理更倾向于将谷氨酸转化为丙酮酸和丙氨酸，而不是丙酮酸和丙氨酸；BS处理对三元酸循环的中间产物(柠檬酸、乌头酸和苹果酸)没有显著影响，但促进了水分胁迫下白三叶中乳酸、乙醇酸、甘油酸、莽草酸、半乳糖醛酸和奎尼酸等有机酸的积累。此外，在水分胁迫下，BS还显著提高了白三叶体内重要的抗氧化代谢产物半胱氨酸的含量。这些改变的氨基酸和有机酸代谢可能在白三叶的生长维持和渗透与氧化还原平衡的调节中发挥重要作用。目前的发现为BS诱导的代谢动态平衡与植物的生长和水分胁迫耐受性提供了新的见解。
Main conclusion beta-sitosterol influences amino acids, carbohydrates, organic acids, and other metabolite metabolism and homeostasis largely contributing to better tolerance to water stress in white clover. beta-sitosterol (BS) could act as an important plant growth regulator when plants are subjected to harsh environmental conditions. Objective of this study was to examine effects of BS on growth and water stress tolerance in white clover based on physiological responses and metabolomics. White clover was pretreated with or without BS and then subjected to water stress for 7 days in controlled growth chambers. Physiological analysis demonstrated that exogenous application of BS (120 mu M) could significantly improve stress tolerance associated with better growth performance and photosynthesis, higher leaf relative water content, and less oxidative damage in white clover in response to water stress. Metabolic profiling identified 78 core metabolites involved in amino acids, organic acids, sugars, sugar alcohols, and other metabolites in leaves of white clover. For sugars and sugar alcohol metabolism, the BS treatment enhanced the accumulation of fructose, glucose, maltose, and myo-inositol contributing to better antioxidant capacity, growth maintenance, and osmotic adjustment in white clover under water stress. The application of BS was inclined to convert glutamic acid into proline, 5-oxoproline, and chlorophyll instead of going to pyruvate and alanine; the BS treatment did not significantly affect intermediates of tricarboxylic acid cycle (citrate, aconitate, and malate), but promoted the accumulation of other organic acids including lactic acid, glycolic acid, glyceric acid, shikimic acid, galacturonic acid, and quinic acid in white clover subjected to water stress. In addition, cysteine, an important antioxidant metabolite, was also significantly improved by BS in white clover under water stress. These altered amino acids and organic acids metabolism could play important roles in growth maintenance and modulation of osmotic and redox balance against water stress in white clover. Current findings provide a new insight into BS-induced metabolic homeostasis related to growth and water stress tolerance in plants.