Data_Sheet_1_Comprehensive metabolic analyses provide new insights into primary and secondary metabolites in different tissues of Jianghua Kucha tea (Camellia sinensis var. assamica cv. Jianghua).docx

BackgroundJianghua Kucha (JHKC) is a special tea germplasm with enriched specialized secondary metabolites, including theacrine, non-epimeric flavanols and methylated flavanols. Moreover, primary metabolites provide precursors and energy for the production of secondary metabolites. However, the accumulation patterns of primary and secondary metabolites in different tissues of JHKC are unclear.
MethodsThe changes of primary and secondary metabolites and related metabolic pathways (primary and secondary metabolism) in different JHKC tissues (the bud, 1st-4th leaves, and new stem) were investigated via metabolomics analysis with ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS).
ResultsSignificant differences were observed in 68 primary and 51 secondary metabolites mainly related with the pathways of starch and sucrose, amino acids, caffeine, and flavanols metabolism and TCA cycle. The bud exhibited higher levels of glucose-6-phosphate, citric acid, most amino acids, theobromine, catechin-gallate, epicatechin-gallate, procyanidins, and theasinensins; the 1st leaf showed higher levels of caffeine and epigallocatechin-3-gallate; and the 4th leaf contained higher levels of most monosaccharides, theacrine, and epigallocatechin-3-O-(3”-O-methyl)-gallate. In addition, primary metabolites and important secondary metabolites had certain correlations.
ConclusionThis study provides comprehensive insight into primary and secondary metabolites in JHKC and offers guidelines for efficiently utilizing specialized metabolites of JHKC in the future.

研究背景：江华苦茶（Jianghua Kucha, JHKC）是一类富含特殊次生代谢产物的特色茶种质资源，其所含的特殊次生代谢产物包括苦茶碱（theacrine）、非差向异构黄烷醇以及甲基化黄烷醇。此外，初生代谢产物可为次生代谢产物的合成提供前体物质与能量。然而，目前关于江华苦茶不同组织中初生与次生代谢产物的积累模式尚不清楚。
研究方法：本研究采用超高效液相色谱-四极杆飞行时间质谱（ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry, UHPLC-QTOF/MS）代谢组学分析技术，对江华苦茶不同组织（芽、第1-4叶及新生茎）中的初生与次生代谢产物及相关代谢通路（初生代谢与次生代谢）的变化进行了系统探究。
研究结果：本研究共鉴定出68种初生代谢产物与51种次生代谢产物，其差异积累主要涉及淀粉与蔗糖代谢、氨基酸代谢、咖啡因代谢、黄烷醇代谢以及三羧酸循环（TCA cycle）通路。其中，芽部的葡萄糖-6-磷酸、柠檬酸、多数氨基酸、可可碱、儿茶素没食子酸酯、表儿茶素没食子酸酯、原花青素及茶辛素（theasinensins）含量较高；第1叶中咖啡因与表没食子儿茶素-3-没食子酸酯含量更高；而第4叶则含有更高水平的多数单糖、苦茶碱以及表没食子儿茶素-3-O-(3”-O-甲基)-没食子酸酯。此外，初生代谢产物与重要次生代谢产物之间存在一定的相关性。
研究结论：本研究全面解析了江华苦茶中的初生与次生代谢产物特征，可为未来高效开发利用江华苦茶的特色次生代谢产物提供理论指导。