Genome-wide characterization of glycosyltransferases involved in C-glycosylation and the metabolism of small molecules in the tea plant (Camellia sinensis)

茶树（Camellia sinensis）中参与 C-糖基化和小分子代谢的糖基转移酶的全基因组表征

• 批准号: 431536455
• 负责人: Professor Dr. Wilfried Schwab
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/431536455?language=en
• 关键词: Genome; wide; characterization; glycosyltransferases; involved

Leaves and leaf buds of the tea plant (Camellia sinensis) used to make tea are a rich source of bioactive phytochemicals that frequently occur as O- and C-glycoconjugates. C-glycosides show biological activity similar to the respective O-glycoside, but display at the same time a substantially improved stability against in vivo clearance, which make them attractive for medicinal chemistry. Uridine diphosphate-sugar (UDP)-dependent glycosyltransferases (UGTs) usually mediate glycosylation of plant metabolites by catalysing the transfer of an activated nucleotide sugar donor to a range of acceptor aglycones to form glycosides. Although glycoside precursors determine tea plant performance as well as the quality of the product tea, the genes and enzymes involved in the glycosylation of small molecules, especially the C- glycosylation in the tea plant, are rarely studied. Only recently, the Chinese partners have published the genome sequence of C. sinensis var. sinensis, which provided insights into the evolution of the tea genome and tea quality. Since the German and Chinese partners have extensive experience in the biotechnological production of small molecule glucosides and the characterization of plant UGTs, respectively, as demonstrated by several joint publications, it is now possible to characterize the genes and enzymes involved in the biosynthesis of low-molecular glycosides in tea plants and to facilitate their biotechnological production. We identified 298 UGT family 1 genes in the tea genome database. In the current project, the Chinese and German groups would like to investigate the genome expansion mechanisms by bioinformatics analysis and isolate all UGT family 1 genes from the tea plant. It is planned to express the recombinant proteins in host organisms, identify potential donor and acceptor substrates by high-throughput screens and investigate the biological function of selected candidates by overexpression and downregulation in transgenic plant systems. The activity of the UGTs will be analysed by both in vitro assays and biotransformation experiments. Functional characterization of candidates will be performed in planta in Arabidopsis thaliana, Nicotiana benthamiana and Camellia sinensis as well as by comparative transcriptome and metabolite profiling analyses. The focus will be on UGTs involved in the C-glycosylation, the metabolism of aroma chemicals and plant defence. These results will provide the foundation for improvement of tea flavour and tea plant defence, as well as the biotechnological production of bioactive C-glycosides with improved stability against hydrolysis.

用于泡茶的茶树（Camellia sinensis）的叶子和叶芽是生物活性植物化学物质的丰富来源，通常以O-和c -糖缀合物的形式出现。c -糖苷表现出与o -糖苷相似的生物活性，但同时具有显著提高的抗体内清除稳定性，这使得它们在药物化学中具有吸引力。尿苷二磷酸糖（UDP）依赖的糖基转移酶（UGTs）通常通过催化活化的核苷酸糖供体转移到一系列受体苷元形成糖苷来介导植物代谢物的糖基化。虽然糖苷前体决定了茶树的生产性能和成品茶的质量，但参与小分子糖基化的基因和酶，特别是茶树中的C-糖基化，却很少被研究。直到最近，中国合作伙伴才公布了中华茶变种的基因组序列，这为茶叶基因组的进化和茶叶质量提供了见解。由于德国和中国合作伙伴在小分子糖苷的生物技术生产和植物ugt的表征方面分别拥有丰富的经验，正如几篇联合出版物所证明的那样，现在有可能表征茶树中低分子糖苷生物合成所涉及的基因和酶，并促进其生物技术生产。我们在茶叶基因组数据库中鉴定出298个UGT家族1基因。在目前的项目中，中国和德国的团队希望通过生物信息学分析来研究茶树的基因组扩增机制，并从茶树中分离出UGT家族1的所有基因。计划在宿主生物中表达重组蛋白，通过高通量筛选鉴定潜在的供体和受体底物，并通过转基因植物系统中的过表达和下调来研究选择的候选物的生物学功能。ugt的活性将通过体外测定和生物转化实验进行分析。候选植物的功能表征将在拟南芥、烟和山茶中进行，并通过比较转录组和代谢物分析。重点将放在参与c -糖基化、芳香化学物质代谢和植物防御的ugt上。这些结果将为改善茶叶风味和茶树防御能力以及生物技术生产具有抗水解稳定性的生物活性c -糖苷提供基础。