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。芥子油苷是一种化合物，使芥菜/卷心菜/花椰菜家族的蔬菜具有特有的辛辣味道，是氨基酸的代谢产物。芥子油苷保护植物免受昆虫和食草动物的取食，还具有抗病原体的特性。此外，芥子油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，了解硫苷合成的调控。拟南芥ATR 1蛋白是合成由色氨酸衍生的吲哚芥子油苷（IG）所需基因的关键正调控因子。ATR 1的高表达增加IG水平，并且ATR 1的失活导致部分IG缺乏。该项目的目标是了解更多关于拟南芥中IG合成的调控，特别关注ATR 1的作用。将测试与ATR 1高度相关的蛋白质是否也在IG调节中起作用，或在其他芥子油苷合成途径的调节中起作用。区分蛋白质的结构特征，如ATR 1，专门控制IG合成将被解剖。与此同时，将使用生物化学和遗传学方法鉴定ATR 1介导其激活作用的靶向DNA序列。拟南芥基因组的完整注释以及IG上调的简易测定提供了一个前所未有的机会，以充分了解这一重要植物代谢途径的调控网络。更广泛的影响：该项目将阐明硫代葡萄糖苷基因是如何调节的，并为调节农业植物中的硫代葡萄糖苷提供独特的工具，以提高其抗虫性和病原体抗性。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.