Regulation of Tryptophan Metabolism in Arabidopsis

植物产生大量对发育和防御至关重要的代谢物。硫代葡萄糖苷是一种由氨基酸衍生的代谢物，这种化合物使芥菜/卷心菜/西兰花家族的蔬菜具有独特的辛辣味道。硫代葡萄糖苷保护植物免受昆虫和食草动物的取食，并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。实验室的芥菜拟南芥提供了一个强大的实验系统，在其中了解硫代葡萄糖苷合成的调节。拟南芥ATR1蛋白是合成吲哚硫代葡萄糖苷(IG‘s)所需基因的关键正调控因子，这些IG来源于氨基酸色氨酸。ATR1的高表达会增加IG水平，而ATR1的失活会导致部分IG缺乏。这个项目的目标是更多地了解拟南芥中IG合成的调控，特别是ATR1的作用。与ATR1高度相关的蛋白质将接受测试，以确定它们是否也参与IG调节或其他硫代葡萄糖苷合成途径的调节。我们将剖析区分ATR1等特定控制IG合成的蛋白质的结构特征。同时，将使用生化和遗传方法鉴定ATR1靶向介导其激活效应的DNA序列。对拟南芥基因组的完整注释以及对IG上调的简便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，以此作为提高它们对昆虫和病原体抗性的一种手段。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.