Liu Haijiao, Su Yingwei, Fan Yunxia, Zuo Denghong, Xu Jie, Liu Yixiang, Mei Xinyue, Huang Huichuan, Yang Min, Zhu Shusheng
State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China.
Key Laboratory for Agro-Biodiversity and Pest Control of Ministry of Education, Yunnan Agricultural University, Kunming, China.
Front Plant Sci. 2023 Apr 19;14:1175878. doi: 10.3389/fpls.2023.1175878. eCollection 2023.
saponins (PNSs) are used as industrial raw materials to produce many drugs to treat cardio-cerebrovascular diseases. However, it is a heat-sensitive plant, and its large-scale artificial cultivation is impeded by high temperature stress, leading to decreases in productivity and PNSs yield. Here, we examined exogenous foliar leucine to alleviate heat stress and explored the underlying mechanism using metabolomics. The results indicated that 3 and 5 mM exogenous foliar leucine significantly alleviated heat stress in one-year- and two-year-old in pots and field trials. Exogenous foliar leucine enhanced the antioxidant capacity by increasing the activities of antioxidant enzymes (POD, SOD) and the contents of antioxidant metabolites (amino acids). Moreover, exogenous foliar leucine enhanced carbohydrate metabolism, including sugars (sucrose, maltose) and TCA cycle metabolites (citric acid, aconitic acid, succinic acid and fumaric acid), in leaves, stems, and fibrous roots to improve the energy supply of plants and further alleviate heat stress. Field experiments further verified that exogenous foliar leucine increased the productivity and PNSs accumulation in . These results suggest that leucine application is beneficial for improving the growth and quality of under heat stress. It is therefore possible to develop plant growth regulators based on leucine to improve the heat resistance of and other crops.
人参皂苷（PNSs）被用作工业原料来生产许多治疗心脑血管疾病的药物。然而，人参是一种热敏性植物，高温胁迫阻碍了其大规模人工种植，导致产量和PNSs产量下降。在此，我们研究了外源叶面喷施亮氨酸以缓解热胁迫，并利用代谢组学探究其潜在机制。结果表明，在盆栽和田间试验中，3 mM和5 mM外源叶面喷施亮氨酸显著缓解了一年生和两年生人参的热胁迫。外源叶面喷施亮氨酸通过提高抗氧化酶（POD、SOD）的活性和抗氧化代谢物（氨基酸）的含量来增强抗氧化能力。此外，外源叶面喷施亮氨酸增强了人参叶片、茎和须根中的碳水化合物代谢，包括糖类（蔗糖、麦芽糖）和三羧酸循环代谢物（柠檬酸、乌头酸、琥珀酸和富马酸），以改善植物的能量供应并进一步缓解热胁迫。田间试验进一步证实，外源叶面喷施亮氨酸提高了人参的产量和PNSs积累。这些结果表明，施用亮氨酸有利于提高热胁迫下人参的生长和品质。因此，有可能开发基于亮氨酸的植物生长调节剂来提高人参和其他作物的耐热性。
