Molecular Genetics of Amino Acid Biosynthesis in Arabidopsis

我们研究的目的是确定氨基的特征， 利用拟南芥的植物特有的酸生物合成 thaliana. 我们提出了一种分子遗传学方法， 通过分离色氨酸来剖析色氨酸途径， 需要突变体 这条途径特别重要 在植物中由于其在生长素的生物合成中的作用， 类黄酮、木质素前体和其它酚类化合物。 其中一个突变体的荧光 分离的Trp将用作遗传标记，以获得更多的Trp 突变体，并了解色氨酸 生物合成到激素IAA的产生。 作为 互补的方法，我们将克隆基因编码的 色氨酸生物合成酶 的完整序列 其中一个基因，色氨酸合成酶， 已被克隆的将被确定。 所克隆基因 用作探针将揭示调节机制，激素 控制和细胞内定位。 我们分析 谷氨酸合酶（GOGAT）应该提供关键信息 关于氨基酸代谢和 光合作用 我们对HMG CoA还原酶的分析应该 还提供了重要的见解， 对植物来说是新的类固醇生物合成。 与 克隆的还原酶基因作为探针， 激素（赤霉素和脱落酸）对 这种酶的调节。 一株色氨酸营养缺陷型拟南芥的分离 Thaliana是氨基酸的第一个例子。 植物中的营养缺陷型 这样的突破打开了一个领域 研究植物基因调控和代谢的方法， 这在以前是不可能的。

The goal of our studies is to determine the features of amino acid biosynthesis unique to plants using Arabidopsis thaliana. We propose a molecular genetic approach to the dissection of the tryptophan pathway by isolating tryptophan- requiring mutants. This pathway is of particular importance in plants because of its role in the biosynthesis of auxin, flavanoids, lignin precursor and other phenolic compounds. The fluorescence of one of the mutants we have already isolated will be used as a genetic marker to obtain more Trp mutants and to understand the relationship of tryptophan biosynthesis to the production of the hormone IAA. As a complementary approach, we will clone the genes encoding the tryptophan biosynthetic enzymes. The complete sequence of one of these genes, the tryptophan synthetase, which has already been cloned will be determined. The cloned genes used as probes will reveal mechanisms of regulation, hormonal control, and intracellular localization. Our analysis of the glutamate synthase (GOGAT) should provide key information about the relationship between amino acid metabolism and photosynthesis. Our analysis of the HMG CoA reductase should also provide important insights concerning the aspects of steroid biosynthesis that are novel to plants. With the cloned reductase gene as a probe we will able to determine the effects of hormones (gibberilins and abcissic acid) on the regulation of this enzyme. The isolation of a tryptophan auxotroph of Arabidopsis thaliana was of the first demonstrations of amino acid auxotrophy in plants. Such a breakthrough opens up an area of inquiry into plant gene regulation and metabolism which has not been previously possible.