Song SaSa, Tao Yu, Gao LongHan, Liang HuiLing, Tang DeSong, Lin Jie, Wang YuChun, Gmitter Frederick G, Li ChunFang
College of Tea Science and Tea Culture, Zhejiang A&F University, Hangzhou, China.
Institute of Food and Agricultural Sciences, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States.
Front Plant Sci. 2022 May 19;13:880227. doi: 10.3389/fpls.2022.880227. eCollection 2022.
Purple tea plant cultivars, enrich with flavonoids and anthocyanins, are valuable materials for manufacturing tea with unique color and flavor. Researchers found that 'Zijuan' leaves changed from purple to green mainly caused by the decreased flavonoids and anthocyanins concentrations. The mechanism of flavonoids and anthocyanin biosynthesis has been studied in many purple tea plant cultivars and the key genes which regulated the biosynthesis of flavonoid and anthocyanins in different purple tea plant cultivars were quite different. Also, the molecular regulation mechanism underlying the flavonoids and anthocyanins biosynthesis during leaves development and color changes is less-thoroughly understood. In this study, an integrative analysis of transcriptome and metabolome was performed on the purple leaves and green leaves of 'Zijuan' tea plant to reveal the regulatory networks correlated to flavonoid biosynthesis and to identify key regulatory genes. Our results indicated that the 'Zijuan' new shoots leaves were purple might be due to the copigmentation of quercetin and kaempferol derivatives. In 'Zijuan' tea plant cultivar, flavonoids metabolites concentrations in purple leaves and green leaves were significantly influenced by the genes involved in flavonoid biosynthesis, transcriptional regulation, transport, and hormone response. Transcription factors including NAC008, MYB23, and bHLH96 and transporters such as ABC transporter I might be responsible for the flavonoid and anthocyanins accumulation in purple leaves. This study provides a new insight into the metabolism and molecular mechanisms underlying flavonoid and anthocyanin biosynthesis in tea plant.
紫茶品种富含黄酮类化合物和花青素，是制造具有独特色泽和风味茶叶的宝贵原料。研究人员发现，‘紫娟’叶片从紫色变为绿色主要是由于黄酮类化合物和花青素浓度降低所致。许多紫茶品种中都对黄酮类化合物和花青素生物合成的机制进行了研究，不同紫茶品种中调控黄酮类化合物和花青素生物合成的关键基因差异很大。此外，叶片发育和颜色变化过程中黄酮类化合物和花青素生物合成的分子调控机制尚不完全清楚。在本研究中，对‘紫娟’茶树的紫色叶片和绿色叶片进行了转录组和代谢组的综合分析，以揭示与黄酮类化合物生物合成相关的调控网络并鉴定关键调控基因。我们的结果表明，‘紫娟’新梢叶片呈紫色可能是由于槲皮素和山奈酚衍生物的共色素作用。在‘紫娟’茶树品种中，紫色叶片和绿色叶片中黄酮类化合物代谢物的浓度受到参与黄酮类化合物生物合成、转录调控、转运和激素应答的基因的显著影响。包括NAC008、MYB23和bHLH96在内的转录因子以及ABC转运蛋白I等转运体可能是紫色叶片中黄酮类化合物和花青素积累的原因。本研究为茶树中黄酮类化合物和花青素生物合成的代谢及分子机制提供了新的见解。
