Tang Dingzhong, Ade Jules, Frye Catherine A, Innes Roger W
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Plant J. 2005 Oct;44(2):245-57. doi: 10.1111/j.1365-313X.2005.02523.x.
We have identified an Arabidopsis mutant that displays enhanced disease resistance (edr2) to the biotrophic powdery mildew pathogen Erysiphe cichoracearum. Inhibition of fungal growth on edr2 mutant leaves occurred at a late stage of the infection process and coincided with formation of necrotic lesions approximately 5 days after inoculation. Double-mutant analysis revealed that edr2-mediated resistance is suppressed by mutations that inhibit salicylic acid (SA)-induced defense signaling, including npr1, pad4 and sid2, demonstrating that edr2-mediated disease resistance is dependent on SA. However, edr2 showed normal responses to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000. EDR2 appears to be constitutively transcribed in all tissues and organs and encodes a novel protein, consisting of a putative pleckstrin homology (PH) domain and a steroidogenic acute regulatory protein-related lipid-transfer (START) domain, and contains an N-terminal mitochondrial targeting sequence. The PH and START domains are implicated in lipid binding, suggesting that EDR2 may provide a link between lipid signaling and activation of programmed cell death mediated by mitochondria.
我们鉴定出了一种拟南芥突变体，它对活体营养型白粉病病原体菊苣白粉菌表现出增强的抗病性（edr2）。在感染过程的后期，真菌在edr2突变体叶片上的生长受到抑制，且这与接种后约5天坏死病斑的形成同时发生。双突变分析表明，edr2介导的抗性被抑制水杨酸（SA）诱导防御信号传导的突变所抑制，这些突变包括npr1、pad4和sid2，这表明edr2介导的抗病性依赖于SA。然而，edr2对细菌病原体番茄丁香假单胞菌番茄致病变种DC3000表现出正常反应。EDR2似乎在所有组织和器官中组成型转录，编码一种新型蛋白质，该蛋白质由一个假定的普列克底物蛋白同源（PH）结构域和一个类固醇生成急性调节蛋白相关脂质转运（START）结构域组成，并含有一个N端线粒体靶向序列。PH和START结构域与脂质结合有关，这表明EDR2可能在脂质信号传导与线粒体介导的程序性细胞死亡激活之间建立联系。
