Zhou Ying, He Wei, He Yunchuan, Chen Qiulin, Gao Yang, Geng Jiamei, Zhu Zeng-Rong
Hainan Institute, Zhejiang University, Yazhou District, Sanya 572025, China.
College of Agriculture and Biotechnology, Zhejiang University, Xihu District, Hangzhou 310030, China.
Food Chem (Oxf). 2023 Jun 2;6:100173. doi: 10.1016/j.fochms.2023.100173. eCollection 2023 Jul 30.
Linalool and its derivatives contribute greatly to tea aroma. Here, 8-hydroxylinalool was found to be one of the major linalool-derived aroma compounds in var. 'Hainan dayezhong', a tea plant grown in Hainan Province, China. Both ()-8-hydroxylinalool and ()-8-hydroxylinalool were detected, and the type was the main compound. Its content fluctuated in different months and was the highest in the buds compared with other tissues. CsCYP76B1 and CsCYP76T1, located in the endoplasmic reticulum, were identified to catalyze the formation of 8-hydroxylinalool from linalool in the tea plant. During withering of black tea manufacturing, the content of both ()-8-hydroxylinalool and ()-8-hydroxylinalool significantly increased. Further study suggested that jasmonate induced gene expression of and , and the accumulated precursor linalool may also contribute to 8-hydroxylinalool accumulation. Thus, this study not only reveals 8-hydroxylinalool biosynthesis in tea plants but also sheds light on aroma formation in black tea.
芳樟醇及其衍生物对茶叶香气有很大贡献。在此,8-羟基芳樟醇被发现是中国海南省种植的茶树品种‘海南大叶种’中主要的芳樟醇衍生香气化合物之一。检测到(+)-8-羟基芳樟醇和(-)-8-羟基芳樟醇,且(+)型为主要化合物。其含量在不同月份波动,与其他组织相比,在芽中含量最高。位于内质网的CsCYP76B1和CsCYP76T1被鉴定为催化茶树中芳樟醇形成8-羟基芳樟醇。在红茶制作的萎凋过程中,(+)-8-羟基芳樟醇和(-)-8-羟基芳樟醇的含量均显著增加。进一步研究表明,茉莉酸诱导CsCYP76B1和CsCYP76T1的基因表达,积累的前体芳樟醇也可能有助于8-羟基芳樟醇的积累。因此,本研究不仅揭示了茶树中8-羟基芳樟醇的生物合成,也为红茶香气形成提供了线索。