Involvement of Salicylic Acid Inhibition of Catalase and Ascorbate Peroxidase in Plant Defense Responses

摘要：研究发现，水杨酸（Klessig Salicylic acid， SA）在激活植物对微生物攻击的防御反应中起重要作用。本实验室已鉴定出一种SA结合蛋白，它是一种过氧化氢酶，其活性被SA阻断。要验证的假设是H2O2和其他活性氧水平的增加诱导植物抗性（PR）基因（PR）。本实验将研究SA对过氧化氢酶和抗坏血酸过氧化物酶（另一种H202降解酶）的抑制作用，以及PR基因抗性基因的诱导作用。在感染部位测定SA、H2O2和PR mRNA水平的时间过程。通过引入编码分解水杨酸的酶的nahG基因而制成的转基因植物将被检查并以多种方式与野生型植物进行比较。转基因植物与抑制过氧化氢酶或抗坏血酸过氧化物酶的水平，通过引入反义这些酶也将被检查。这些实验将提供水杨酸如何在植物防御反应中起作用的信息。＊＊＊

Abstract 9514239 Klessig Salicylic acid (SA) has been found to play an important role in the activation of defense responses against microbial attack in plants. This laboratory has identified a SA binding protein, which is a catalase, and its activity is blocked by SA. The hypothesis to be tested is that increased levels of H2O2 and other reactive oxygen species induce plant resistance (PR) genes (PR . In this proposal experiments will be done to study the role of catalase and ascorbate peroxidase (another H202 degrading enzyme) inhibition by SA, as well as he induction of PR gene resistant genes. The time course of the levels of SA, H2O2 and PR mRNA will be determined at the sites of infection. Plants made transgenic by the introduction of the nahG gene, which codes for the enzyme that breaks down salicylic acid will be examined and compared in a number of way to the wild type plants. Transgenic plants with suppressed levels of catalase or ascorbate peroxidase, made by introducing antisense to these enzymes will also be examined. These experiments will provide information on how salicyclic acids acts in the plant defense response. ***