Schwessinger Benjamin, Bahar Ofir, Thomas Nicholas, Holton Nicolas, Nekrasov Vladimir, Ruan Deling, Canlas Patrick E, Daudi Arsalan, Petzold Christopher J, Singan Vasanth R, Kuo Rita, Chovatia Mansi, Daum Christopher, Heazlewood Joshua L, Zipfel Cyril, Ronald Pamela C
Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, California, United States of America; Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America.
Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, California, United States of America.
PLoS Pathog. 2015 Mar 30;11(3):e1004809. doi: 10.1371/journal.ppat.1004809. eCollection 2015 Mar.
Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.
植物质膜定位的模式识别受体（PRRs）可检测细胞外病原体相关分子。诸如拟南芥EFR和水稻XA21等PRRs在分类学上具有局限性，在大多数植物基因组中并不存在。在此我们表明，表达EFR或嵌合受体EFR::XA21（包含EFR胞外结构域和XA21胞内结构域）的水稻植株能够感知来自大肠杆菌和水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae，Xoo）的elf18肽，其浓度低至亚纳摩尔。用elf18处理EFR和EFR::XA21水稻叶片组织会导致丝裂原活化蛋白激酶激活、活性氧产生和防御基因表达。虽然EFR的表达不会导致对完全致病的Xoo分离株产生强大的增强抗性，但确实会导致对弱致病的Xoo分离株产生定量增强的抗性。EFR与水稻XA21介导的免疫反应的两个关键组分OsSERK2和XA21结合蛋白24（XB24）相互作用。沉默OsSERK2或过表达水稻XB24的水稻-EFR植株在elf18诱导的活性氧产生和防御基因表达方面受损，这表明这些蛋白对于转基因水稻中EFR介导的信号传导也很重要。综上所述，我们的结果证明了通过表达双子叶植物PRRs来增强水稻以及可能其他单子叶作物品种抗病性的潜在可行性。我们的结果还表明，拟南芥EFR利用了已知的水稻XA21内源信号传导组分中的至少一部分。
