Correlation Between Spatiotemporal Profiles of Volatile Terpenoids and Relevant Terpenoid Synthase Gene Expression in Camellia sinensis
Correlation Between Spatiotemporal Profiles of Volatile Terpenoids and Relevant Terpenoid Synthase Gene Expression in Camellia sinensis
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茶树挥发性萜类化合物时空谱与相关萜类合酶基因表达的相关性
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Liu Jing
中科院分区：
文献类型：
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作者：
Liu Jing
单萜和倍半萜是茶叶中主要的香气成分，对茶叶品质有重要影响。本研究旨在阐明茶树鲜叶中挥发性萜类化合物生物合成的分子机制。利用GC-MS技术建立了茶树叶片和花中挥发性萜类化合物的谱图。不同发育阶段的茶树叶片和花中挥发性萜类化合物的含量差异较大。嫩叶比老叶含有更多的萜类化合物，且糖苷结合萜类化合物的含量高于游离萜类化合物。利用生物信息学方法对茶树萜类化合物合成酶基因进行了定位。在茶树中发现了以下10种萜类化合物脱氢酶的编码基因：芳樟醇合酶、月桂烯合酶、（E）-β-罗勒烯合酶、（R）-柠檬烯合酶、（-）-α-松油醇合酶、（+）-α-水芹烯合酶、大根香叶烯D合酶、（E，E）-α-法呢烯合酶、芳樟醇/橙花叔醇合酶和橙花叔醇/香叶基芳樟醇合酶。基因表达谱分析揭示了茶树中受试基因的时空模式。此外，它们的表达模式与挥发性萜类化合物的丰度呈正相关。此外，茉莉酸甲酯（MeJA）诱导了6个萜类化合物合成酶基因的表达，这表明通过这些基因表达调控可以在实践中提高芳香萜类化合物的排放特性。
Monoterpenes and sesquiterpenes are the major tea aromatic compounds and important for tea quality. In this study,efforts were made to elucidate the molecular mechanism controlling volatile terpenoid biosynthesis in fresh tea leaves. Volatile terpenoid profiles in tea leaves and flowers were constructed using GC–MS technology. Tea leaves and flowers at different developmental stages exhibited distinct profiles of volatile terpenoids. Young leaves had more abundant terpenoids than old leaves,and the amount of glycosidically bound terpenoids were higher than free ones. Bioinformatics approaches were employed to map tea terpenoid synthase genes from previously obtained tea transcriptome data. Genes encoding for the following ten terpenoid synthases in tea were found:Linalool synthase,myrcene synthase,(E)-β-ocimene synthase,(R)-limonene synthase,(-)-α-terpineol synthase,(+)-α-phellandrene synthase, germacrene D synthase,(E,E)-α-farnesene synthase, linalool/nerolidol synthase and nerolidol/geranyl linalool synthase. Gene expression profiling revealed spatiotemporal patterns of the tested genes in tea plants. Moreover,their expression patterns were positively correlated to the abundance of volatile terpenoids. Additionally,the expression of six terpenoid synthase genes were induced by methyl jasmonate(MeJA),suggesting that emission profile of aromatic terpenoids might be enhanced in practice through these gene expression manipulation.