How does tea (Camellia sinensis) produce specialized metabolites which determine its unique quality and function: a review

Abstract

Tea (Camellia sinensis) is both a plant and a foodstuff. Many bioactive compounds, which are present in the final tea product and related to its quality or functional properties, are produced during the tea manufacturing process. However, the characteristic secondary metabolites, which give tea its unique qualities and are beneficial to human health, are produced mainly in the leaves during the process of plant growth. Therefore, it is important to understand how tea leaves produce these specialized metabolites. In this review, we first compare the common metabolites and specialized metabolites in tea, coffee, cocoa, and grape and discuss the occurrence of characteristic secondary metabolites in tea. Progress in research into the formation of these characteristic secondary metabolites in tea is summarized, including establishing a biological database and genetic transformation system, and the biosynthesis of characteristic secondary metabolites. Finally, speculation on future research into the characteristic secondary metabolites of tea is provided from the viewpoints of the origin, resources, cultivation, and processing of tea. This review provides an important reference for future research on the specialized metabolites of tea in terms of its characteristics.

Keywords:

• Camellia sinensis
• tea
• quality
• specialized metabolite
• platform
• biosynthesis

Acknowledgements

We thank Prof. Zhenbiao Yang at the University of California at Riverside for helpful comments on the manuscript structure, and Dr. Luchao Lv at the South China Agricultural University for the review and revision on the information of tea genome from different cultivars. Because of space limitations, we could not cite all publications in the field; we apologize to all colleagues whose work has not been mentioned.

Author contributions

LZ, YL, and XZ wrote the manuscript. All authors reviewed the manuscript.

Additional information

Funding

A part of the research aspects done by the authors are supported by the financial supports from the National Natural Science Foundation of China (31922077, 31902073, 31870684, and 31670690), the Natural Science Foundation of Guangdong Province (2020A1515010007), the Basic Frontier Science Research Program of Chinese Academy of Sciences (ZDBS-LY-SM032), the Regional Key Project of Science and Technology Service Network Plan of Chinese Academy of Sciences (KFJ-STS-QYZX-093), the China Postdoctoral Science Foundation (2018M640837), the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (2019LM1143), the National Key Research and Development Program of China (2018YFD1000601), the Guangdong Special Support Plan for Training High-Level Talents (2016TQ03N617), and the Foundation of Science and Technology Program of Guangzhou (201804010097).