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

摘要9514239已发现Klessig水杨酸(SA)在激活植物对微生物侵袭的防御反应中发挥重要作用。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。需要检验的假设是，过氧化氢和其他活性氧物种水平的增加会诱导植物抗性(PR)基因(PR)。在本方案中，我们将通过实验研究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，以及对PR基因抗性基因的诱导。在感染部位测定SA、H_2O_2和PR mRNA水平的时程变化。通过引入nahG基因获得的转基因植物将被检测，并在许多方面与野生型植物进行比较。nahG基因编码分解水杨酸的酶。通过向过氧化氢酶或抗坏血酸过氧化物酶引入反义基因而获得的过氧化氢酶或抗坏血酸过氧化物酶水平被抑制的转基因植物也将被检测。这些实验将提供有关水杨酸如何在植物防御反应中发挥作用的信息。***

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. ***