Falk A, Feys B J, Frost L N, Jones J D, Daniels M J, Parker J E
The Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom.
Proc Natl Acad Sci U S A. 1999 Mar 16;96(6):3292-7. doi: 10.1073/pnas.96.6.3292.
A major class of plant disease resistance (R) genes encodes leucine-rich-repeat proteins that possess a nucleotide binding site and amino-terminal similarity to the cytoplasmic domains of the Drosophila Toll and human IL-1 receptors. In Arabidopsis thaliana, EDS1 is indispensable for the function of these R genes. The EDS1 gene was cloned by targeted transposon tagging and found to encode a protein that has similarity in its amino-terminal portion to the catalytic site of eukaryotic lipases. Thus, hydrolase activity, possibly on a lipid-based substrate, is anticipated to be central to EDS1 function. The predicted EDS1 carboxyl terminus has no significant sequence homologies, although analysis of eight defective eds1 alleles reveals it to be essential for EDS1 function. Two plant defense pathways have been defined previously that depend on salicylic acid, a phenolic compound, or jasmonic acid, a lipid-derived molecule. We examined the expression of EDS1 mRNA and marker mRNAs (PR1 and PDF1.2, respectively) for these two pathways in wild-type and eds1 mutant plants after different challenges. The results suggest that EDS1 functions upstream of salicylic acid-dependent PR1 mRNA accumulation and is not required for jasmonic acid-induced PDF1.2 mRNA expression.
植物抗病（R）基因的一大类编码富含亮氨酸重复序列的蛋白质，这些蛋白质具有核苷酸结合位点，并且在氨基末端与果蝇Toll蛋白和人类白细胞介素-1受体的胞质结构域相似。在拟南芥中，EDS1对于这些R基因的功能是不可或缺的。通过靶向转座子标签法克隆了EDS1基因，发现其编码的蛋白质在氨基末端部分与真核脂肪酶的催化位点相似。因此，预计水解酶活性（可能作用于基于脂质的底物）是EDS1功能的核心。预测的EDS1羧基末端没有明显的序列同源性，尽管对八个有缺陷的eds1等位基因的分析表明它对EDS1功能至关重要。先前已经定义了两种植物防御途径，它们分别依赖于水杨酸（一种酚类化合物）或茉莉酸（一种脂质衍生分子）。我们检测了野生型和eds1突变体植物在不同刺激后这两种途径的EDS1 mRNA以及标记mRNA（分别为PR1和PDF1.2）的表达。结果表明，EDS1在水杨酸依赖性PR1 mRNA积累的上游起作用，而茉莉酸诱导的PDF1.2 mRNA表达不需要EDS1。
