Differential accumulation of specialized metabolite l-theanine in green and albino-induced yellow tea (Camellia sinensis) leaves

Abstract l -Theanine is a specialized metabolite in tea ( Camellia sinensis ) leaves that contributes to tea function and quality. Yellow tea leaves (albino) generally have higher l -theanine contents than green tea leaves (normal), but the reason is unknown. The objective of this study was to investigate why l -theanine is accumulated in yellow tea leaves. We compared original normal leaves (green) and light-sensitive albino leaves (yellow) of cv. Yinghong No. 9. The l -theanine content was significantly higher in yellow leaves than in green leaves ( p  ≤ 0.01). After supplementation with [ 2 H 5 ]- l -theanine, yellow leaves catabolized less [ 2 H 5 ]- l -theanine than green leaves ( p  ≤ 0.05). Furthermore, most plants contained the enzyme catalyzing l -theanine conversion to ethylamine and l -glutamic acid. In conclusion, l -theanine accumulation in albino-induced yellow tea leaves was due to weak l -theanine catabolism. The differential accumulation mechanism differed from the l -theanine accumulation mechanism in tea and other plants.