RUI: Flavonoid Glucosyltransferase Clones From Citrus paradisi; Function, Metabolic Impact, and Structural Characterization

本项目的总体研究重点是研究特定类黄酮（主要的酚类代谢产物）的生物合成调控，以阐明植物发育和生长过程中控制类黄酮合成、代谢和积累的因素。一个主要的重点领域是葡萄糖基转移酶（GTs）的调节，这种酶将葡萄糖添加到不同种类的类黄酮中，从而产生实际存在于植物组织中的化合物。通过对不同植物基因组的序列分析，可以预测出100多种可能的次生产物GTs；只有相对较少的这些基因产物被功能表征，其中大多数属于一组在3-OH位置向黄酮醇和/或花青素添加葡萄糖的GTs。这项研究使用葡萄柚作为模型系统，因为这种植物已被证明具有作用于不同类黄酮的GT酶。此外，一些候选克隆已经可以用于表征。本研究的具体目的是验证葡萄柚叶片推定的GT克隆是次生产物GT，特别是类黄酮GT的假设，以及它们具有可能在生化水平上受到调节的特性。此外，将启动旨在通过确定这些蛋白质的特定结构特征是否对其独特特性负责来测试与GT结构/功能相关的假设的研究。更广泛的影响：本研究为东田纳西州立大学的本科生和硕士研究生提供了高质量的培训和教育机会，东田纳西州立大学是一所位于经济落后地区的本科院校。它还为博士后研究助理提供了一个获得经验和必要技能的机会，以便在本科机构中形成一个活跃的研究项目，并开展研究活动，以支持教学和指导学生的研究。该项目的基础科学和现代方法将为每周实验室会议和期刊俱乐部的讨论提供一个很好的出发点。此外，项目人员将参与加强K-12科学教育的外展活动。

The overall research focus of this project is to study regulation of biosynthesis of specific flavonoids (a major group of phenolic metabolites) to elucidate factors that control flavonoid synthesis, metabolism, and accumulation during plant development and growth. A major emphasis area is on regulation of enzymes called glucosyltransferases (GTs) that add glucose to different classes of flavonoids resulting in production of the compounds actually found in plant tissues. Well over 100 putative secondary product GTs can be predicted from sequence analysis of various plant genomes; only a relatively small number of these gene products have been functionally characterized and the majority of these belong to a group of GTs that add glucose to flavonols and/or anthocyanins at the 3-OH position. This research uses grapefruit as the model system as this plant has been shown to have GT enzymes that act on different flavonoids. Also, some candidate clones are already available for characterization. Specific goals of this research are to test the hypotheses that the grapefruit leaf putative GT clones are secondary product GTs, specifically flavonoid GTs, and that they have properties that may make them subject to regulation at the biochemical level. In addition, studies designed to test hypotheses related to GT structure/function by determining whether or not particular structural feature(s) of these proteins are responsible for their unique properties will be initiated. Broader Impact: This research provides quality training and educational opportunities to undergraduate students and master's level graduate students at East Tennessee State University, a primarily undergraduate institution located in an economically disadvantaged region. It also provides an opportunity for a postdoctoral research associate to obtain experience and requisite skills for forming an active research program at an undergraduate institution and developing research activities in support of teaching and mentoring student research. The basic science and modern approach of this project will provide a good launching point for discussions during weekly lab meetings and journal clubs. In addition, the project personnel will be involved in outreach activities to strengthen K-12 science education.