Pti4 is induced by ethylene and salicylic acid, and its product is phosphorylated by the Pto kinase
Pti4 is induced by ethylene and salicylic acid, and its product is phosphorylated by the Pto kinase
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DOI：
10.1105/tpc.12.5.771
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发表时间：
2000-05-01
期刊：
影响因子：
11.6
通讯作者：
Martin, GB
中科院分区：
文献类型：
--
作者：
Gu, YQ;Yang, C;Martin, GB
番茄Pti4基因编码一种转录因子，该转录因子是根据其与酵母双杂交系统中Pto抗病基因产物的特异性相互作用而被鉴定的。我们在此表明，Pti4 蛋白特异性结合 GCC-box 顺式元件，该元件存在于许多发病机制相关 (PR) 基因的启动子区域。乙烯和丁香假单胞菌番茄致病变种感染可快速诱导番茄叶中 Pti4 基因的表达，并且这种诱导先于含有 GCC-box 的 PR 基因表达。虽然水杨酸也诱导Pti4基因表达，但它不诱导GCC-box PR基因。相反，水杨酸拮抗乙烯介导的 GCC-box PR 基因的表达。我们证明 Pti4 蛋白被 Pto 激酶特异性磷酸化，并且这种磷酸化增强了 Pti4 与 GCC 盒的结合。此外，番茄叶片中 Pto 和 Pti4 的诱导过度表达导致 GCC-box PR 基因随之增加。我们的结果支持这样一个模型：Pto 激酶对 Pti4 蛋白的磷酸化增强了 Pti4 激活番茄中 GCC-box PR 基因表达的能力。
The tomato Pti4 gene encodes a transcription factor that was identified on the basis of its specific interaction with the product of the Pto disease resistance gene in a yeast two-hybrid system. We show here that the Pti4 protein specifically binds the GCC-box cis element, which is present in the promoter region of many pathogenesis-related (PR) genes. Expression of the Pti4 gene in tomato leaves was rapidly induced by ethylene and by infection with Pseudomonas syringae pv tomato, and this induction preceded expression of GCC-box-containing PR genes. Although salicylic acid also induced Pti4 gene expression, it did not induce GCC-box PR genes. Rather, salicylic acid antagonized ethylene-mediated expression of GCC-box PR genes. We demonstrate that the Pti4 protein is specifically phosphorylated by the Pto kinase and that this phosphorylation enhances binding of Pti4 to the GCC box. In addition, induced overexpression of Pto and Pti4 in tomato leaves resulted in a concomitant increase in GCC-box PR genes. Our results support a model in which phosphorylation of the Pti4 protein by the Pto kinase enhances the ability of Pti4 to activate expression of GCC-box PR genes in tomato.