Isochorismate synthase is required to synthesize salicylic acid for plant defence
Isochorismate synthase is required to synthesize salicylic acid for plant defence
复制标题
DOI：
10.1038/35107108
复制
发表时间：
2001-11-29
期刊：
影响因子：
64.8
通讯作者：
Ausubel, FM
中科院分区：
文献类型：
--
作者：
Wildermuth, MC;Dewdney, J;Ausubel, FM
水杨酸（SA）介导植物对病原体的防御，响应于病原体攻击而在受感染的叶和远端叶中积累（1-5）。植物中与局部和系统获得性抗性（LAR和SAR）相关的致病相关基因表达和防御化合物的合成需要SA。在拟南芥中，外源施用SA足以建立SAR，导致对多种病原体的抗性增强。然而，尽管SA在植物防御病原体中具有重要性，但其生物合成还没有被很好地定义。先前的研究表明，植物从苯丙氨酸合成SA（6-10）;然而，当该途径被抑制时，SA仍然可以产生（6，8），并且在喂养实验中放射性标记的SA的比活性通常低于预期（7，8）。一些细菌如铜绿假单胞菌使用异分支酸合酶（ICS）和丙酮酸裂解酶合成SA（11）。在这里，我们表明，通过克隆和表征的拟南芥防御相关基因（SID 2）的突变定义，SA是从分支酸合成的ICS的装置，和SA通过这条途径所需的LAR和SAR的反应。
Salicylic acid (SA) mediates plant defences against pathogens, accumulating in both infected and distal leaves in response to pathogen attack(1-5). Pathogenesis-related gene expression and the synthesis of defensive compounds associated with both local and systemic acquired resistance (LAR and SAR) in plants require SA. In Arabidopsis, exogenous application of SA suffices to establish SAR, resulting in enhanced resistance to a variety of pathogens. However, despite its importance in plant defence against pathogens, SA biosynthesis is not well defined. Previous work has suggested that plants synthesize SA from phenylalanine(6-10); however, SA could still be produced when this pathway was inhibited(6,8), and the specirc activity of radiolabelled SA in feeding experiments was often lower than expected(7,8). Some bacteria such as Pseudomonas aeruginosa synthesize SA using isochorismate synthase (ICS) and pyruvate lyase(11). Here we show, by cloning and characterizing an Arabidopsis defence-related gene (SID2) defined by mutation, that SA is synthesized from chorismate by means of ICS, and that SA made by this pathway is required for LAR and SAR responses.