Regulation mechanisms of formation of aroma compounds of tea (Camellia sinensis) leaves and development of technique for improving tea aroma

Polyphenols, amino acids, and aroma compounds are fundamental for tea quality. The content of polyphenols in teas is 18-36% of dry weight, whereas amino acids and aromas account for 1-4% and 0.005-0.03%, respectively. Due to the relative contents of amino acids and aromas in teas, improvement of the amino acids and aromas of tea has recently attracted increased levels of interest.

Research Group of Plant Metabolomics (PI: YANG Ziyin) in South China Botanical Garden currently focuses on the formation of amino acids and aroma compounds in tea in response to biotic and abiotic stresses before/ after harvest, including stress-response mechanisms of the pathways, enzymes, and genes involved in the biosynthesis of these quality-related metabolites, as well as the practical applications for the improvement of tea quality during the cultivation and manufacturing processes. In 2015, we obtained several important findings concerning research of tea aroma. (1) Blue light and red light significantly increased most endogenous volatiles in the preharvest tea leaves. Furthermore, blue and red lights significantly up-regulated the expression levels of genes involved in formation of tea aromas. These results suggest that blue and red lights can be promising technology for remodeling the aromas of preharvest tea leaves. In addition, our study provided evidence that light wavelength can activate the expression of key genes involved in formation of plant volatiles for the first time (See Figure, Sci. Rep., 2015, 5: 16858). (2) The tea leaf cell wall disruption, which was induced by different mechanical damage patterns during the tea manufacturing process, significantly affected the formation of characteristic floral and honey aromas of tea leaves (J. Agr. Food Chem., 2015, 63: 6905-6914). (3) Based on the results of regulation of formation of tea aroma by single factor, a “green integrated techniques”-based technique for improvement of floral and honey aromas of tea leaves has been developed (Patent application, application No. 201510778840.5).

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