Regulation of Tryptophan Metabolism in Arabidopsis

植物产生一系列对发育和防御至关重要的代谢物。硫代葡萄糖苷是一种从氨基酸中提取的代谢物，这种化合物赋予芥菜、卷心菜和西兰花等蔬菜特有的辛辣味道。硫代葡萄糖苷保护植物免受昆虫和食草动物的侵害，也具有抗病原体的特性。此外，硫代葡萄糖苷是人类饮食中的抗癌化合物。实验室芥菜拟南芥提供了一个强大的实验系统，其中了解硫代葡萄糖苷合成的调节。拟南芥ATR1蛋白是合成由色氨酸衍生的吲哚类硫代葡萄糖苷（IG）所需基因的关键正调控因子。ATR1的高表达增加了IG水平，而ATR1的失活导致部分IG缺乏。该项目的目的是了解更多关于拟南芥中IG合成的调控，特别关注ATR1的作用。将检测与ATR1高度相关的蛋白质是否也参与IG调节或其他硫代葡萄糖苷合成途径的调节。将剖析区分ATR1等特异性控制IG合成的蛋白质的结构特征。同时，ATR1靶向介导其激活作用的DNA序列将通过生化和遗传方法进行鉴定。拟南芥基因组的完整注释以及简便的IG上调分析为充分了解这一重要植物代谢途径的调控网络提供了前所未有的机会。更广泛的影响：该项目将阐明硫代葡萄糖苷基因是如何被调控的，并提供独特的工具来调节农业植物中的硫代葡萄糖苷，作为提高其抗虫和病原体能力的手段。该项目还将为研究生和本科生提供植物遗传学和分子生物学方面的培训。

Plants produce a wide array of metabolites critical for development and defense. Glucosinolates, the compounds that give vegetables in the mustard/cabbage/broccoli family their characteristic pungent flavor, are metabolites derived from amino acids. Glucosinolates defend plants against insect and herbivore feeding and also have anti-pathogen properties. In addition, glucosinolates are anti-cancer compounds in the human diet. The laboratory mustard Arabidopsis provides a powerful experimental system in which to understand the regulation of glucosinolate synthesis. The Arabidopsis ATR1 protein is a key positive regulator of genes needed to synthesize indolic glucosinolates (IG's) derived from the amino acid tryptophan. High expression of ATR1 increases IG levels, and inactivation of ATR1 causes a partial IG deficiency. The goal of this project is to understand more about the regulation of IG synthesis in Arabidopsis with a particular focus on the role of ATR1. Proteins that are highly related to ATR1 will be tested for whether they also act in IG regulation, or in regulation of other glucosinolate synthesis pathways. The structural features that distinguish proteins like ATR1 that specifically control IG synthesis will be dissected. In parallel, the DNA sequences that are targeted by ATR1 to mediate its activating effects will be identified using biochemical and genetic approaches. The complete annotation of the Arabidopsis genome together with facile assays for IG upregulation offer an unprecedented opportunity to fully understand the regulatory network for this important plant metabolic pathway. Broader Impacts: The project will elucidate how glucosinolate genes are regulated, and provide unique tools for modulating glucosinolates in agricultural plants as a means to improve their insect and pathogen resistance. The project will also provide training in plant genetics and molecular biology for graduate and undergraduate students.