Characterization of the Salicylic Acid Signal Transduction Pathway in Plant Defense Responses

Klessig 9723952植物防御反应中水杨酸信号转导途径的表征 越来越多的证据表明，水杨酸（SA）是一个重要的内源性信号所需的激活和/或增强防御反应的局部和系统的阻力。 这项研究将继续研究，以确定，克隆和表征SA信号转导途径的组成部分，导致激活防御反应，特别是病程相关（PR）基因的表达。两个主要目标将继续追求：i）表征拟南芥突变体与改变SA信号转导和ii）PR-2d启动子结合蛋白的表征可能参与SA响应。 遗传、分子和生物化学方法的组合正在拟南芥和烟草（烟草）中使用。遗传方法包括分离和表征拟南芥突变体和构建转基因拟南芥和烟草植物以鉴定和表征SA/防御信号传导途径的顺式和反式作用组分。分子方法包括克隆、DNA测序、Southern、北方和Western印迹、酵母单杂交和双杂交筛选、定点诱变和重组蛋白的产生。蛋白质纯化、酶分析和蛋白质-DNA或蛋白质-蛋白质相互作用的表征代表了一些用于进一步表征潜在途径组分的生化工具。病毒（烟草花叶病毒TMV和芜菁皱缩病毒TCV）和细菌（假单胞菌pv番茄，斑点或烟粉虱）病原体都被用来激活防御途径，并研究其组成部分。 抗性植物和易感植物之间的一个关键区别是入侵病原体的及时识别和宿主防御的快速有效激活。因此，研究植物抗病性的主要目的之一是鉴定和表征植物组分，这些组分对于导致这些宿主防御激活的信号转导过程至关重要。这些成分的鉴定和表征对于我们理解抗病机制至关重要。此外，通过遗传和分子方法对它们进行操纵为提高植物抗病性提供了令人兴奋的前景。

Klessig 9723952 Characterization of the Salicylic Acid Signal Transduction Pathway in Plant Defense Responses An ever increasing body of evidence indicates that salicylic acid (SA) is an important endogenous signal required for activation and/or potentiation of defense responses in both local and systemic resistance. This research will continue studies to identify, clone, and characterize the components of the SA signal transduction pathway(s) which lead to activation of defense responses, in particular pathogenesis-related (PR) gene expression. Two major objectives will continue to be pursued: i) characterization of Arabidopsis mutants with altered SA signal transduction and ii) characterization of PR-2d promoter binding proteins potentially involved in SA responsiveness. A combination of genetic, molecular, and biochemical approaches are being utilized in Arabidopsis and Nicotiana tabacum (tobacco). Genetic approaches include isolation and characterization of Arabidopsis mutants and construction of transgenic Arabidopsis and tobacco plants to identify and characterize cis- and trans-acting components of the SA/defense signaling pathway(s). Molecular approaches include cloning, DNA sequencing, Southern, northern, and western blotting, yeast one- and two-hybrid screening, site-directed mutagenesis, and production of recombinant proteins. Protein purification, enzyme analysis, and characterization of protein-DNA or protein-protein interactions represent some of' the biochemical tools that are being used to further characterize potential pathway components. Both viral (tobacco mosaic virus TMV and turnip crinkle virus TCV ) and bacterial (Pseudomonas syringae pv tomato, maculicola, or tabaci) pathogens are being used to activate the defense pathway(s) and study its components. A key difference between resistant and susceptible plants is the timely recognition of the invading pathogen and the rapid and effective activation of host defenses. Thus, one of the major aims of stu dying plant disease resistance is to identify and characterize plant components which are crucial for the signal transduction processes leading to activation of these host defenses. Identification and characterization of these components are essential to our understanding of the mechanisms of disease resistance. Furthermore, their manipulation through genetic and molecular approaches offers the exciting prospect of enhancing plant disease resistance.