Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA.
Plant Cell. 2010 Feb;22(2):508-22. doi: 10.1105/tpc.109.068874. Epub 2010 Feb 23.
Pep1 is a 23-amino acid peptide that enhances resistance to a root pathogen, Pythium irregulare. Pep1 and its homologs (Pep2 to Pep7) are endogenous amplifiers of innate immunity of Arabidopsis thaliana that induce the transcription of defense-related genes and bind to PEPR1, a plasma membrane leucine-rich repeat (LRR) receptor kinase. Here, we identify a plasma membrane LRR receptor kinase, designated PEPR2, that has 76% amino acid similarity to PEPR1, and we characterize its role in the perception of Pep peptides and defense responses. Both PEPR1 and PEPR2 were transcriptionally induced by wounding, treatment with methyl jasmonate, Pep peptides, and pathogen-associated molecular patterns. The effects of Pep1 application on defense-related gene induction and enhancement of resistance to Pseudomonas syringae pv tomato DC3000 were partially reduced in single mutants of PEPR1 and PEPR2 and abolished completely in double mutants. Photoaffinity labeling and binding assays using transgenic tobacco (Nicotiana tabacum) cells expressing PEPR1 and PEPR2 clearly demonstrated that PEPR1 is a receptor for Pep1-6 and that PEPR2 is a receptor for Pep1 and Pep2. Our analysis demonstrates differential binding affinities of two receptors with a family of peptide ligands and the corresponding physiological effects of the specific receptor-ligand interactions. Therefore, we demonstrate that, through perception of Peps, PEPR1 and PEPR2 contribute to defense responses in Arabidopsis.
Pep1 是一种 23 个氨基酸的肽，可增强对根病原体腐霉的抗性。Pep1 及其同源物（Pep2 至 Pep7）是拟南芥先天免疫的内源性增强子，可诱导防御相关基因的转录，并与质膜富含亮氨酸重复（LRR）受体激酶 PEPR1 结合。在这里，我们鉴定了一种质膜 LRR 受体激酶，命名为 PEPR2，它与 PEPR1 具有 76%的氨基酸相似性，并且我们描述了它在 Pep 肽感知和防御反应中的作用。PEPR1 和 PEPR2 均受创伤、茉莉酸甲酯、Pep 肽和病原体相关分子模式的转录诱导。在 pep1 突变体和 pep2 突变体中，Pep1 处理对防御相关基因诱导和增强对丁香假单胞菌 pv 番茄 DC3000 的抗性的影响部分降低，在 pep1 双突变体中完全消除。使用表达 PEPR1 和 PEPR2 的转基因烟草（Nicotiana tabacum）细胞进行的光亲和标记和结合测定清楚地表明，PEPR1 是 Pep1-6 的受体，PEPR2 是 Pep1 和 Pep2 的受体。我们的分析表明，两种受体与肽配体家族具有不同的结合亲和力，以及特定受体-配体相互作用的相应生理效应。因此，我们证明通过 Pep 的感知，PEPR1 和 PEPR2 有助于拟南芥的防御反应。
