Analysis Of Differentially Expressed Proteins Associated With Regulation Of Anthocyanin Metabolism In ’Zijuan’ Tea(Camellia Sinensis Var.Kitamura)

Anthocyanin,one of water-soluble pigments,is widespread in plant organs,such as flowers,fruits,leaves,and so on.Several health-promoting benefits of anthocyanin have been found,including antioxidation,anti-cancer activity,hypolipidemic effects,liver protection and anti-aging.Reddishviolet·shoot tea is a special type of tea with purple buds and young leaves,containing a lot of anthocyanin.The purple and green leaves of ’Zijuan5 Tea {Camellia sinensis var.kitamura),a typical reddishviolet-shoot tea,was studied in this paper.Isobaric Tag for Relative and Absolute Quantification(iTRAQ)was carried out for quantification of proteins extracted from the purple and green leaves,and 815 differentially expressed proteins were identified,of which 271 were down-regulated,and the other 544 proteins were up-regulated.20 proteins associated with regulation of anthocyanin metabolism were screened out.And based on the analysis of the 20 proteins and some physiological and biochemical data,a regulatory network of anthocyanin metabolism in ’Zijuan’ Tea was established as the following:(1)Proteins related to anthocyanin biosynthesis,including CHS,CHI,DFR,ANS,were up-regulated under the regulation of transcription factors bHLH and HY5,which promoted anthocyanin synthesis;(2)Anthocyanin was rapidly glycosylated by UFGT and then was transferred to vacuole by ABC transporter,which contributed to the stability and accumulation of anthocyanin in cells;(3)More phenylalanine perhaps was synthesized from shikimic acid pathway under the regulation of up-regulated DHQ and CM,which supplied enough raw substrates for anthocyanin synthesis;(4)The activity of lignin synthesis was reduced under the regulation of CCR,CAD,POD and LAC,resulting in more intermediate metabolites flowing into anthocyanin synthesis pathway.However,a part of downstream metabolites were catalyzed into flavonol,catechin and epicatechin by FLS,LAR and ANR,which actually leading to the decrease of anthocyanin.These results will lay the theoretical basis of molecular biology for breeding new tea germplasms with high content of anthocyanins and flavonoids.