Metabolomics analysis reveals the metabolic and functional roles of flavonoids in light-sensitive tea leaves.
As the predominant secondary metabolic pathway in tea plants, flavonoid biosynthesis increases with increasing temperature and illumination. However, the concentration of most flavonoids decreases greatly in light-sensitive tea leaves when they are exposed to light, which further improves tea quality. To reveal the metabolism and potential functions of flavonoids in tea leaves, a natural light-sensitive tea mutant (Huangjinya) cultivated under different light conditions was subjected to metabolomics analysis.



The results showed that chlorotic tea leaves accumulated large amounts of flavonoids with ortho-dihydroxylated B-rings (e.g., catechin gallate, quercetin and its glycosides etc.), whereas total flavonoids (e.g., myricetrin glycoside, epigallocatechin gallate etc.) were considerably reduced, suggesting that the flavonoid components generated from different metabolic branches played different roles in tea leaves. Furthermore, the intracellular localization of flavonoids and the expression pattern of genes involved in secondary metabolic pathways indicate a potential photoprotective function of dihydroxylated flavonoids in light-sensitive tea leaves.



Our results suggest that reactive oxygen species (ROS) scavenging and the antioxidation effects of flavonoids help chlorotic tea plants survive under high light stress, providing new evidence to clarify the functional roles of flavonoids, which accumulate to high levels in tea plants. Moreover, flavonoids with ortho-dihydroxylated B-rings played a greater role in photo-protection to improve the acclimatization of tea plants.
Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310058, China.|Key Laboratory for Plant Biology and Resource Application of Tea, the Ministry of Agriculture, South Meiling Road 9, Hangzhou, Zhejiang, 310008, China.
Qunfeng
Q
Zhang
Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310058, China.|Key Laboratory for Plant Biology and Resource Application of Tea, the Ministry of Agriculture, South Meiling Road 9, Hangzhou, Zhejiang, 310008, China.
Meiya
M
Liu
Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310058, China. jruan@tricaas.com.|Key Laboratory for Plant Biology and Resource Application of Tea, the Ministry of Agriculture, South Meiling Road 9, Hangzhou, Zhejiang, 310008, China. jruan@tricaas.com.
Jianyun
J
Ruan
D028241:Camellia sinensis / Q000378:metabolism* / Q000528:radiation effects; D002392:Catechin / Q000031:analogs & derivatives / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism; D008027:Light; D053858:Metabolic Networks and Pathways / Q000528:radiation effects; D055432:Metabolomics; D018515:Plant Leaves / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
D005419:Flavonoids; D006027:Glycosides; D017382:Reactive Oxygen Species; C417939:catechin gallate; D002392:Catechin; C045651:epigallocatechin gallate
Camellia sinensis; Flavonoids; Light sensitive; Metabolism; Photo-protection