Signal Transduction Pathways of the Plant Oxidative Burst

[9725934]刘志强，刘志强。氧化爆发是植物抗病的重要早期防御机制。爆发反应的特点是在病原体或病原体产生的激发子分子刺激植物细胞后几分钟内迅速合成高活性氧化合物（超氧化物或过氧化氢）。因为这种氧气爆发在整个植物界都有发现，而且它可能是几种植物防御机制的关键组成部分，所以它的详细描述是相当重要和有趣的。该项目的总体目标是阐明当激发子与细胞表面或细胞质受体结合时激活的信号转导途径，并在氧化酶复合物组装和激活以产生活性氧爆发时达到高潮。具体目的是(a)表征启动对低聚半乳糖醛酸反应的特定激发物激活的蛋白激酶，(b)确定可能的中间组分（g蛋白，ca++，磷脂酶C，其他蛋白激酶）的激活时间，这些中间组分将产生的信号传递给氧化酶以激活它，以及(C)克隆激酶和几个氧化酶亚基的基因。这些目标的完成将极大地增强我们对导致氧化爆发的特定信号转导过程的理解，并将为植物细胞信号转导策略的一般原理提供见解。这项工作的一个实际扩展是，如果氧化爆发可以被设计成更快或对更广泛的病原体做出反应，那么农业对有毒农药的依赖就可以减少。

9725934 Low, Philip S. The oxidative burst constitutes an important early defense mechanism linked to disease resistance in plants. The burst response is characterized by the rapid synthesis of highly reactive oxygen compounds (superoxide or hydrogen peroxide) within minutes after stimulation of the plant cell by pathogens or pathogen-generated elicitor molecules. Because this oxygen burst is found throughout the plant kingdom, and since it may be a critical component of several plant defense mechanisms, its detailed characterization is of considerable importance and interest. The overall goal of this project is to elucidate the signal transduction pathway that is activated when an elicitor binds to a cell surface or cytoplasmic receptor and which culminates when the oxidase enzyme complex is assembled and activated to produce the burst of reactive oxygen. The specific aims are (a) to characterize a specific elicitor-activated protein kinase that initiates the response to oligogalacturonic acid, (b) to determine the timing of activation of possible intermediate components (G-proteins, Ca++, phospholipase C, other protein kinases) that relay the resulting signal to the oxidase to activate it, and (c) to clone the genes for both the kinase and several of the oxidase subunits. Completion of these objectives will greatly enhance our understanding of the specific signal transduction processes that lead to the oxidative burst and will provide insights into general principles of signal transduction strategies in plant cells. One practical extension of this work is that if the oxidative burst can be engineered to respond more rapidly or to a wider range of pathogens, reliance on toxic pesticides in agriculture could be reduced.