茉莉酸甲酯诱导茶叶香气成分变化的机理研究

Methyl Jasmonate (MeJA) , which is very common in nature plant populations, can act as a signal substance to regulate the secondary metabolism of plant. MeJA can induce plant to generate volatile components and therefore improve the aroma quality of gardenstuff,which has attracted much attention in recent years and became one of the hot topics in the field of plant physiology.Our previous research showed that the composition of volatile aroma components in tea leaves has changed obviously after treated with MeJA, and at the same time the tea aroam quality was promoted significantly, providing a new way of thinking for the improvement of tea aroma.Thus, for the purpose of revealing the mechanism of aroma constituents change in tea induced by MeJA, this current study will adopt advanced method such as proteomics, plant molecular biology and 1H-NMR based metabonomics, to analyze the the protein and genes related to the biology metabolization of aroma substances as well as its biochemical processes. Moreover, UPLC-Q-TOF/MS and GC-MS will also be applied to study the change of aroam components and its some aromatic precursors during the tea processing.This study is of great theoretical significance and practical value. Further recongniztion will be done to the the biology metabolization of aroma substances induced by MeJA, and new theoretical guide will be provided for the tea aroam improvement.

茉莉酸甲酯（MeJA）是植物体内普遍存在的，具有调节次生代谢作用的信号物质。近年来利用茉莉酸甲酯诱导植物产生挥发性物质，改善果蔬香气品质等研究备受关注。我们前期的研究结果表明，茉莉酸甲酯处理茶树能够明显改变鲜叶中的挥发物组成，提高成品茶的香气，这为今后改善茶叶香气品质提供了一条新的思路。本研究拟在前期研究基础上，采用蛋白组学、分子生物学和基于NMR的代谢组学等先进分析手段，研究与香气物质代谢的相关蛋白、基因表达、关键酶活性的变化，分析茉莉酸甲酯处理后其生物化学过程变化的规律；采用UPLC-Q-TOF/MS、GC-MS等研究鲜叶中香气前体物及挥发性香气成分在加工过程中的消长变化，以期揭示茉莉酸甲酯诱导茶叶香气成分变化的机理。本研究在理论上有助于加深对茉莉酸甲酯调节茶树香气物质代谢的认识，在实践上可为今后开发提高茶叶香气品质的新技术提供理论指导，具有重要的理论意义和实际应用价值。

本项目采用转录组学、蛋白组学以及代谢组学等手段，对茉莉酸甲酯诱导茶叶香气成分变化的机理进行了系统研究，取得主要研究结果如下：① 茉莉酸甲酯诱导后，茶树鲜叶中发生差异变化的代谢途径主要集中在：α-亚麻酸代谢途径、萜烯骨架合成途径、类胡萝卜素代谢途径以及类苯基丙烷代谢途径，同时我们确定了这些途径中香气合成相关的关键差异变化基因与蛋白质。② 茉莉酸甲酯诱导后，茶树鲜叶中糖苷化次生代谢产物大量积累，茉莉酸甲酯，香叶醇，芳樟醇及其氧化物，β-紫罗酮等香气物质含量增加，较对照都在2倍以上，加工成绿茶，乌龙茶，红茶，香气品质都有显著提高。③ 多组学数据整合及分析表明，茉莉酸甲酯诱导后，α-亚麻酸代谢途径中大量合成茉莉酸，并激活全局性JA-Pathway，同时鲜叶中茉莉酸类物质大量衍生化旨在去茉莉酸活性过程(甲基化，羟基化，糖苷化)；萜烯骨架合成途径中细胞质非甲羟戊酸部分具有显著的茉莉酸甲酯诱导响应现象，大量GPP（萜类化合物前体）以及GGPP（类胡萝卜素前体）在细胞质中大量积累，萜烯醇类糖苷化次生代谢产物合成种类显著增加，含量也有很大程度的提升，较对照样品达3倍以上（12h, 24h, 48h）该糖苷化次生代谢产物是茶叶加工过程中释放出游离态萜烯醇类香气物质的直接前体。本研究加深了对茉莉酸甲酯调节茶树香气物质代谢的认识，对于今后提高茶叶香气品质，完善加工技术手段具有重要的指导意义和实际应用价值。