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

9310371 Klessig自1985年以来，我们的小组一直在研究发病机制相关（PR）蛋白的各个方面，包括它们的位置，它们在抗病性中的功能和它们的合成。 最近在我们的工作，以及其他几个，实验室强烈表明，水杨酸（SA）起着重要的信号作用，在植物疾病防御反应，包括诱导PR基因。 我们建议继续几条线的研究，以帮助进一步确定SA的信号作用，并确定该信号转导通路的组成部分。 烟草抗病品种在感染烟草花叶病毒（TMV）后，除了游离SA外，还存在一种糖苷化形式（SAG）。 这两种形式的SA在系统获得性抗性（SAR）的发展和表现中的作用将得到解决。 研究的第二条线涉及表征的顺式元件（S）和反式作用因子介导SA诱导的转录激活的酸性PR-2（葡聚糖酶）基因的烟草。 在研究的第三线中，将分离和表征拟南芥的SA不敏感（SAIN）突变体。 SAIN突变体的阳性选择将利用与SA诱导型烟草PR-1或PR-2启动子融合的根癌土壤杆菌的tms 2基因. 这些研究应该导致更好地了解SA信号是如何产生的，修改，感知和转导防御反应。 它们还可以提供对其他SA介导的生理变化的作用机制的见解，并且应该提供将植物中的信号转导与微生物和动物中的信号转导进行比较的机会。 ***

9310371 Klessig Since 1985 our group has been studying various aspects of pathogenesis related (PR) proteins including their location, their function in disease resistance and their synthesis. Recent work in our, as well as several other, laboratories strongly suggests that salicylic acid (SA) plays an important signaling role in plant disease defense responses including the induction of PR genes. We propose to continue several lines of study to help further define SA's signaling role and identify components of this signal transduction pathway. In addition to free SA, a glucosidated form (SAG) is found in resistant cultivate of tobacco after infection with tobacco mosaic virus (TMV). The roles of these two forms of SA in the development and manifestation of systemic acquired resistance (SAR) will be addressed. The second line of study involves characterization of the cis element (s) and trans-acting factors which mediate SA-induced transcriptional activation of the acidic PR-2 (glucanase) gene of tobacco. In the third line of study SA-insensitive (SAIN) mutants of Arabidopsis will be isolated and characterized. Positive selection of SAIN mutants will utilize the tms2 gene of Agrobacterium tumefaciens fused to the SA- inducible tobacco PR-1 or PR-2 promoters. %%% These studies should lead to a better understanding of how the SA signal is generated, modified, perceived and transduced during defense responses. They may also provide insights into the mechanisms (s) of action of other SA-mediated physiological changes and should provide an opportunity to compare signal transduction in plants with that in microbes and animals. ***