Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
J Agric Food Chem. 2020 Sep 16;68(37):10109-10117. doi: 10.1021/acs.jafc.0c04381. Epub 2020 Sep 2.
Linalool is abundant in tea leaves and contributes greatly to tea aroma. The two isomers of linalool, ()-linalool and ()-linalool, exist in tea leaves. Our study found that ()-linalool was the minor isomer in nine of var. cultivars. The ()-linalool synthase of tea plant CsRLIS was identified subsequently. It is a chloroplast-located protein and specifically catalyzes the formation of ()-linalool and . was observed to be a stress-responsive gene and caused the accumulation of internal ()-linalool during oolong tea manufacture, mechanical wounding, and insect attack. Further study demonstrated that the catalytic efficiency of CsRLIS was much lower than that of ()-linalool synthase CsSLIS, which might explain the lower ()-linalool proportion in var. cultivars. The relative expression levels of and may also affect the ()-linalool proportions among var. cultivars. This information will help us understand differential distributions of chiral aroma compounds in tea.
芳樟醇在茶叶中含量丰富，对茶叶香气贡献极大。芳樟醇有两种顺式异构体，即（-）-芳樟醇和（+）-芳樟醇，存在于茶叶中。我们的研究发现，在 9 个 var. 品种中，（-）-芳樟醇都是含量较少的异构体。随后鉴定出茶树 CsRLIS 的（-）-芳樟醇合酶。它是一种定位于叶绿体的蛋白，特异性地催化（-）-芳樟醇和 的形成。 被观察到是一个应激响应基因，导致在乌龙茶加工、机械损伤和昆虫攻击过程中内部（-）-芳樟醇的积累。进一步的研究表明，CsRLIS 的催化效率远低于（-）-芳樟醇合酶 CsSLIS，这可能解释了 var. 品种中（-）-芳樟醇比例较低的原因。 和 的相对表达水平也可能影响 var. 品种中（-）-芳樟醇的比例。这些信息将有助于我们理解手性香气化合物在茶叶中的差异分布。
