Zhang Gaoyang, Yang Jihong, Cui Dandan, Zhao Dandan, Li Yingying, Wan Xiaochun, Zhao Jian
State Key Laboratory of Tea Plant Biology and Utilization, College of Tea and Food Science and Technology, Anhui Agricultural University, 130 West Changjiang Road, Hefei 230036, China.
J Agric Food Chem. 2020 Mar 18;68(11):3528-3538. doi: 10.1021/acs.jafc.9b07737. Epub 2020 Mar 4.
Theaflavins (TFs) are generated by endogenous polyphenol oxidase (PPO)- and peroxidase (POD)-catalyzed catechins oxidation during black tea processing, which needs to be well-controlled to obtain a proper TFs/thearubigins (TRs) ratio for better quality. Not all leaves from any tea plant cultivars or varieties are suitable for making high-quality black teas, regardless of the processing techniques. The mechanisms underlying TFs formation and the main factors determining the tea leaf processing suitability are not fully understood. We here integrated transcriptome and metabolite profiling of tea leaves to unveil how enzymes or metabolites in leaves are changed during black tea processing. The information enabled us to identify several PPO and POD genes potentially involved in tea processing for TF production. We characterized a POD gene, whose recombinant enzyme showed TF creation activity. The capacity for POD-catalyzed TF production could be used as a molecular marker for breeding tea plant varieties suitable for high-quality black tea production.
茶黄素（TFs）是在红茶加工过程中由内源性多酚氧化酶（PPO）和过氧化物酶（POD）催化儿茶素氧化生成的，为了获得质量更好的茶，需要对其进行良好控制以获得合适的茶黄素/茶红素（TRs）比例。无论采用何种加工技术，并非任何茶树品种的所有叶片都适合制作高品质红茶。茶黄素形成的机制以及决定茶叶加工适宜性的主要因素尚未完全了解。我们在此整合了茶叶的转录组和代谢物谱，以揭示叶片中的酶或代谢物在红茶加工过程中是如何变化的。这些信息使我们能够鉴定出几个可能参与茶黄素生产的PPO和POD基因。我们鉴定了一个POD基因，其重组酶具有茶黄素生成活性。POD催化茶黄素生成的能力可作为培育适合高品质红茶生产的茶树品种的分子标记。
