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

9310371 Klessig自1985年以来，我们小组一直在研究病程相关(PR)蛋白的各个方面，包括它们的位置、它们在抗病中的功能以及它们的合成。我们和其他几个实验室最近的工作有力地表明，水杨酸(SA)在植物的病害防御反应中发挥着重要的信号作用，包括PR基因的诱导。我们建议继续进行几个方面的研究，以帮助进一步确定SA的信号转导作用，并确定该信号转导途径的组成部分。烟草感染烟草花叶病毒(TMV)后，抗性培养中除游离SA外，还存在糖化形式(SAG)。这两种形式的SA在系统性获得性耐药(SAR)的发展和表现中的作用将被讨论。第二条线的研究涉及介导SA诱导烟草酸性PR-2(葡聚糖酶)基因转录激活的顺式元件(S)和反式作用因子的特征。在第三行的研究中，将分离和鉴定拟南芥的SA不敏感(Sain)突变体。SAIN突变体的阳性选择将利用根癌农杆菌的tms2基因与SA诱导的烟草PR-1或PR-2启动子融合。这些研究应该有助于更好地理解SA信号是如何在防御反应中产生、修改、感知和转导的。它们还可以提供对SA介导的其他生理变化的作用机制(S)的见解，并应该提供一个比较植物与微生物和动物中的信号转导的机会。***

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. ***