乌龙茶生产过程中挥发性成分吲哚的形成 | Formation of Volatile Tea Constituent Indole During the Oolong Tea Manufacturing Process

吲哚是啥？在茶叶成分中的地位？乌龙茶？香气，重要的前体，比如色氨酸Trp、IAA。

Indole is a characteristic volatile constituent in oolong tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of oolong tea manufacturing process.

turn over stage of oolong tea manufacturing process是什么阶段？

indole-3-glycerolphosphate lyases：把IGP转化成Indole。在多个植物中同源。

科学问题

(1) How is indole formed in tea leaves? indole在茶叶中是如何形成的？
(2) Why does indole accumulate at the turn over stage of oolong tea manufacturing process?
(3) Why does wounding stress lead to the difference of indole accumulation between oolong tea and black tea?

技术手段和实验

茶叶中的一个TSA和三个TSB被分离、克隆、测序和功能验证了。

In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from tea leaves were isolated, cloned, sequenced, and functionally characterized.

CsTSA和CsTSB2的重组蛋白在大肠杆菌内可以将indole-3-glycerol转化成indole。

Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole.

CsTSB2在turn over过程中高表达。

CsTSB2 was highly expressed during the turn over process of oolong tea.

连续的机械损伤模拟了turn over过程，显著增强了CsTSB2的表达，提高了indole的含量。

Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole.

猜想

indole的积累是因为CsTSB2在连续的物理逆境下激活导致的

These suggested that accumulation of indole in oolong tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process.

红茶只含有少量indole，即使它也包含了物理损伤的过程。

Black teas contain much less indole, although wounding stress is also involved in the manufacturing process.

稳定同位素标记显示茶叶细胞破坏时，红茶没有转化indole，但是却终止了indole的合成。

Stable isotope labeling indicated that tea leaf cell disruption from the rolling process of black tea did not lead to the conversion of indole, but terminated the synthesis of indole.