Thara VK, Tang X, Gu YQ, Martin GB, Zhou JM
Plant J. 1999 Nov;20(4):475-83. doi: 10.1046/j.1365-313x.1999.00619.x.
The tomato genes Pti4 and Pti5 encode ethylene-responsive element binding protein-like transcription factors that bind to the GCC box, a conserved cis-element in many defense-related genes. The Pti proteins have previously been shown to interact with the tomato disease resistance protein Pto. Here we report that the expression of both Pti4 and Pti5 are induced by a virulent strain of Pseudomonas syringae pv tomato. The expression of Pti5 is further enhanced by the interaction of the Pto gene in tomato and the corresponding avrPto gene in the bacterium. The enhancement of Pti5 expression by Pto-avrPto interaction requires a functional Prf gene in the plant. Pti5 appears to be expressed specifically during biotic stresses, suggesting a specific role in plant defense. Pti4 and several EREBP-like genes are induced by ethylene, salicylate and wounding. However, the Pseudomonas bacterium induced a wild-type level of Pti4 and Pti5 transcripts in tomato plants carrying the nahG transgene, the Nr mutation, or the def1 mutation. In addition, the ethylene action inhibitor norbornadiene did not inhibit the induction of Pti4 and Pti5 either in the compatible or incompatible interactions. The results suggest that the Pseudomonas bacterium induces Pti4 and Pti5 expression through a pathway independent of salicylic acid, ethylene and jasmonic acid.
番茄基因Pti4和Pti5编码与乙烯反应元件结合蛋白相似的转录因子，这些转录因子可与GCC框结合，GCC框是许多防御相关基因中的保守顺式元件。此前已表明Pti蛋白可与番茄抗病蛋白Pto相互作用。在此我们报道，丁香假单胞菌番茄致病变种的强毒株可诱导Pti4和Pti5的表达。番茄中的Pto基因与细菌中相应的avrPto基因相互作用可进一步增强Pti5的表达。Pto-avrPto相互作用对Pti5表达的增强需要植物中具有功能正常的Prf基因。Pti5似乎在生物胁迫期间特异性表达，表明其在植物防御中具有特定作用。Pti4和几个类EREBP基因可被乙烯、水杨酸和创伤诱导。然而，丁香假单胞菌在携带nahG转基因、Nr突变或def1突变的番茄植株中诱导出野生型水平的Pti4和Pti5转录本。此外，乙烯作用抑制剂降冰片二烯在亲和或非亲和互作中均不抑制Pti4和Pti5的诱导。结果表明，丁香假单胞菌通过一条独立于水杨酸、乙烯和茉莉酸的途径诱导Pti4和Pti5的表达。
