Shen Jiazhi, Zou Zhongwei, Zhang Xuzhou, Zhou Lin, Wang Yuhua, Fang Wanping, Zhu Xujun
1College of Horticulture, Nanjing Agricultural University, Nanjing, 210095 China.
2Department of Plant Science, University of Manitoba, Winnipeg, MB R3T 2N2 Canada.
Hortic Res. 2018 Feb 7;5:7. doi: 10.1038/s41438-017-0010-1. eCollection 2018.
Purple-leaf tea plants, as anthocyanin-rich cultivars, are valuable materials for manufacturing teas with unique colors or flavors. In this study, a new purple-leaf cultivar "Zixin" ("ZX") was examined, and its biochemical variation and mechanism of leaf color change were elucidated. The metabolomes of leaves of "ZX" at completely purple, intermediately purple, and completely green stages were analyzed using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS). Metabolites in the flavonoid biosynthetic pathway remained at high levels in purple leaves, whereas intermediates of porphyrin and chlorophyll metabolism and carotenoid biosynthesis exhibited high levels in green leaves. In addition, fatty acid metabolism was more active in purple leaves, and steroids maintained higher levels in green leaves. Saponin, alcohol, organic acid, and terpenoid-related metabolites also changed significantly during the leaf color change process. Furthermore, the substance changes between "ZX" and "Zijuan" (a thoroughly studied purple-leaf cultivar) were also compared. The leaf color change in "Zijuan" was mainly caused by a decrease in flavonoids/anthocyanins. However, a decrease in flavonoids/anthocyanins, an enhancement of porphyrin, chlorophyll metabolism, carotenoid biosynthesis, and steroids, and a decrease in fatty acids synergistically caused the leaf color change in "ZX". These findings will facilitate comprehensive research on the regulatory mechanisms of leaf color change in purple-leaf tea cultivars.
紫叶茶树作为富含花青素的品种，是制造具有独特颜色或风味茶叶的宝贵材料。在本研究中，对一个新的紫叶品种“紫鑫”（“ZX”）进行了研究，阐明了其生化变化和叶片颜色变化机制。使用超高效液相色谱四极杆飞行时间质谱（UPLC-QTOF-MS）分析了“ZX”叶片在全紫、中间紫色和全绿阶段的代谢组。黄酮类生物合成途径中的代谢物在紫色叶片中保持高水平，而卟啉和叶绿素代谢以及类胡萝卜素生物合成的中间产物在绿色叶片中含量较高。此外，脂肪酸代谢在紫色叶片中更活跃，类固醇在绿色叶片中保持较高水平。皂苷、醇、有机酸和萜类相关代谢物在叶片颜色变化过程中也发生了显著变化。此外，还比较了“ZX”与“紫娟”（一个已深入研究的紫叶品种）之间的物质变化。“紫娟”的叶片颜色变化主要是由黄酮类/花青素减少引起的。然而，黄酮类/花青素减少、卟啉、叶绿素代谢、类胡萝卜素生物合成和类固醇增强以及脂肪酸减少共同导致了“ZX”的叶片颜色变化。这些发现将有助于对紫叶茶品种叶片颜色变化调控机制进行全面研究。
