Studies on plant immunity in terms of constitutive activated cell death gene, CAD1

植物通过激活称为植物免疫的防御机制来响应生物胁迫，例如病原体感染。植物对病原体攻击的最有效和最直接的抗性反应之一是过敏反应（HR），其导致病原体进入部位的快速局部细胞死亡，从而限制病原体的生长和传播。拟南芥突变体cad 1（组成型激活的细胞死亡1）显示出一种表型，模仿HR样细胞死亡。CAD1基因编码的蛋白质含有与补体成分和穿孔素的MACPF（膜附着复合物和穿孔素）结构域具有显著同源性的结构域，可能会对水杨酸介导的植物免疫产生负面影响。该突变体还增强了植物防御素（PDF1.2）的基因表达，该基因与乙烯和茉莉酸（JA）调控的植物防御途径有关。这些结果表明，突变体对病原菌的抗性与控制乙烯反应基因的ERF蛋白基因有关。使用cad1突变体的微阵列分析揭示了一些可能参与植物防御的ERF基因。ERF基因的特征为：

Plants respond to biotic stress such as pathogen infection by activating a defense mechanism known as plant immunity. One of the most efficient and immediate resistance reactions against pathogen attack in plants is the hypersensitive response (HR), which leads to rapid local cell death at the site of pathogen entry that restricts growth and spread of the pathogen. The Arabidopsis mutant cad1 (constitutively activated cell death 1) shows a phenotype that mimics HR-like cell death. The CAD1 gene, which encodes a protein containing a domain with significant homology to the MACPF (membrane attach complex and perforin) domain of complement components and perforin, is likely to negatively control salicylic acid-mediated plant immunity. The mutant also enhances gene expression of the plant defensin (PDF1.2) which is related to the plant defense pathway regulated by ethylene and jasmonic acid (JA). These results suggest that resistance to the pathogen in the mutant is associated to the genes of ERF protein which controls ethylene-responsive genes. Microarray analysis using the cad1 mutant revealed some gene for the ERF genes which are likely involved in plant defense. Characters of the ERF gene were r