Biosynthesis of Isoflavonoid Phytoalexins in Pea

豌豆中异黄酮植物抗毒素的生物合成

• 批准号: 8916265
• 负责人: Hans. VanEtten
• 金额: $ 22.5万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-15 至 1993-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8916265&HistoricalAwards=false
• 关键词: Biosynthesis; Isoflavonoid; Phytoalexins; Pea

Plants often synthesize antibiotic compounds (phytoalexins) in response to infection, and considerable effort is currently being devoted to research on regulation of their biosynthesis. This research examines some of the terminal, phytoalexin-specific reactions in the biosynthetic pathway for the pea phytoalexins, (+)pisatin and (-)maackiain. The isoflavone reductase which produces the first chiral intermediate of the pathway has been purified and is being characterized. Other enzymes to be studied are pterocarpan synthase, which performs the terminal step of maackiain synthesis, and 6'-deoxychalcone synthase, the first enzyme of the stress-induced branch of the flavonoid pathway. The penultimate step in pisatin synthesis was previously thought to be an oxygenase reaction, but this hypothesis is not consistent with recent findings. Work to be done on this project to resolve this question includes labeling experiments in vivo and enzyme studies. Antibodies against the purified enzymes are being used to obtain corresponding cDNA clones. This approach provides information about how the specificities of the pathway enzymes determine and chemical diversity that exists among legume phytoalexins. Cloned genes for these enzymes can eventually allow further evalation of the role of phytoalexins in disease resistance by modifying the phytoalexin complement of transgenic plants. It is well-established that many plant species synthesize phytoalexins in response to infection by pathogens. It is often proposed that the production of these antimicrobial compounds respresents an active mechanism of defense against potential pathogens. However, direct evidence supporting this hypothesis has been difficult to obtain. Recent work carried out with pea plants and a fungus that causes disease in pea argues that phytoalexins can play an important role in the determination of plant resistance. The goal of this reaearch is to examine phytoalexin biosynthesis in pea. Such findings are useful in addressing interesting questions concerning the regulation of the biosynthetic pathway and the role of phytoalexins in disease resistance. Future implications of this work are novel strategies for enhancing the effectiveness of the phytoalexin defense response.

植物通常合成抗生素化合物（植物抗毒素）， 感染，目前正在作出相当大的努力， 致力于研究其生物合成的调控。 这 研究检查了一些终端，植物抗毒素特异性 豌豆植物抗毒素生物合成途径中的反应， （+）pisatin和（-）maackiain。 该还原酶 产生该途径的第一个手性中间体， 纯化并进行表征。 其他有待研究的酶 是紫檀烷合酶，其执行以下终末步骤： maackiain合成，和6 '-脱氧查耳酮合酶，第一个 类黄酮途径的应激诱导分支的酶。 之前人们认为， 是一种加氧酶反应，但这个假设不是 与最近的调查结果一致。 这个项目要做的工作 为了解决这个问题，包括体内标记实验 和酶研究。 针对纯化酶的抗体是 用于获得相应的cDNA克隆。 这种方法 提供了关于通路的特异性如何 酶决定和化学多样性存在于豆科植物中 植物抗毒素 这些酶的克隆基因最终可以 允许进一步评估植物抗毒素在疾病中的作用 通过修饰转基因植物的植物抗毒素补体 植物 众所周知，许多植物物种 植物抗毒素对病原体感染的反应。 往往 提出这些抗菌化合物的生产 代表了一种积极的防御机制， 病原体 然而，支持这一假设的直接证据 很难获得。 最近用豌豆进行的工作 植物和一种导致豌豆疾病的真菌认为， 植物抗毒素可以在确定 植物抗性 本报告的目的是研究 豌豆中植物防御素的生物合成。 这些发现有助于 处理有关管理的令人感兴趣的问题 植物抗毒素的生物合成途径及其在病害中的作用 阻力 这项工作的未来意义是新颖的 增强植物抗毒素效力的策略 防御反应。