Analysis of Young Shoots of 'Anji Baicha' (Camellia sinensis) at Three Developmental Stages Using Nontargeted LC-MS-Based Metabolomics

摘要

AbstractAnji Baicha (Camellia sinensis) is a lowtemperaturesensitive tea variety. During the development of young shoots, the leaves of Anji Baicha exhibit periodic albinism. The quality of Anji Baicha is closely related to the color of the fresh leaves, with whiter leaves affording a higher amino acid content and superior sensory quality after processing. However, the metabolic mechanism of its quality formation is still unclear. In this study, we analyzed the metabolomic changes of young shoots of Anji Baicha and screened for metabolic markers that may be involved in the periodic albinism. Positive and negativemode UPLCQTOFMS was applied to the metabolomic analysis of young leaves of Anji Baicha during three developmental stages (i.e., the prealbescent, albescent, and regreening stages). The results revealed significant differences in the metabolic profiles of the young leaves at the three stages. The differential metabolites were mainly related to the pathways of flavonoid, phenylpropanoid, and amino acid biosynthesis. The concentrations of several amino acids (primarily ltheanine, lglutamate, N2acetyllornithine, laspartic acid, dproline, lglutamine, lleucine, and pyroglutamic acid) and 12OPDA were significantly higher in the albescent stage. In contrast, during the albescent stages, the concentrations of several carbohydrates (dfructose, dgalactopyranose, 3Ofucopyranosyl2acetamido2deoxyglucopyranose, galactose1, 4xylose acetylmaltose, and 2fucosyllactose) were significantly lower. Moreover, catechins (mainly epigallocatechin and catechin derivatives), dimeric catechins (primarily proanthocyanidins), and flavonol and flavonol/flavone glycosides (mainly kaempferol, myricetin, quercetin, cyanidin, and delphinidin glycosides) were detected at the highest levels in the regreening or prealbescent stages. The obtained results enhance the current understanding of the metabolic mechanisms of periodic albinism and quality development formation in Anji Baicha.Practical ApplicationThe obtained results not only provide information regarding differential metabolites but also advance the understanding of the mechanism of periodic albinism in Anji Baicha at the metabolite level and open up new possibilities for the genetic improvement of tea cultivars.