Identification of a soluble, high-affinity salicylic acid-binding protein in tobacco
Identification of a soluble, high-affinity salicylic acid-binding protein in tobacco
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DOI：
10.1104/pp.113.4.1319
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发表时间：
1997-04-01
期刊：
影响因子：
7.4
通讯作者：
Klessig, DF
中科院分区：
文献类型：
--
作者：
Du, H;Klessig, DF
水杨酸（SA）是植物体内信号转导途径中的一个重要组成部分，在病原菌侵染后可激活植物的某些防御反应。先前的研究已经确定了几种蛋白质，包括过氧化氢酶和抗坏血酸过氧化物酶，SA信号可能通过这些蛋白质起作用。在这里，我们描述了一个新的SA结合蛋白。这种可溶性蛋白质在烟草（Nicotiana tabacum）叶中以低丰度存在，并且具有约25，000的表观分子量。它可逆地结合SA，表观解离常数为90 nm，亲和力比SA和过氧化氢酶之间的亲和力高150倍。SA的大多数类似物与标记SA竞争结合该蛋白的能力与它们诱导防御基因表达和增强抗性的能力相关。引人注目的是，苯并噻二唑，最近描述的化学活化剂，诱导植物防御和抗病性在非常低的应用率，是最强的竞争对手，比未标记的SA更有效。讨论了SA结合蛋白在防御信号转导中的可能作用。
Salicylic acid (SA) is a key component in the signal transduction pathway(s), leading to the activation of certain defense responses in plants after pathogen attack. Previous studies have identified several proteins, including catalase and ascorbate peroxidase, through which the SA signal might act. Here we describe a new SA-binding protein. This soluble protein is present in low abundance in tobacco (Nicotiana tabacum) leaves and has an apparent molecular weight of approximately 25,000. It reversibly binds SA with an apparent dissociation constant of 90 nm, an affinity that is 150-fold higher than that between SA and catalase. The ability of most analogs of SA to compete with labeled SA for binding to this protein correlated with their ability to induce defense gene expression and enhanced resistance. Strikingly, benzothiadiazole, a recently described chemical activator that induces plant defenses and disease resistance at very low rates of application, was the strongest competitor, being much more effective than unlabeled SA. The possible role of this SA-binding protein in defense signal transduction is discussed.