title: Ectopic expression of RESISTANCE TO POWDERY MILDEW8.1 confers resistance to fungal and oomycete pathogens in Arabidopsis.
abstract: Broad-spectrum disease resistance is a highly valuable trait in plant breeding and attracts special attention in research. The Arabidopsis gene locus RESISTANCE TO POWDERY MILDEW 8 (RPW8) contains two adjacent homologous genes, RPW8.1 and RPW8.2, and confers broad-spectrum resistance to powdery mildew. Remarkably, the RPW8.2 protein is specifically localized to the extrahaustorial membrane (EHM) encasing the feeding structure of powdery mildew whereby RPW8.2 activates haustorium-targeted defenses. Here, we show that ectopic expression of the yellow fluorescent protein (YFP)-tagged RPW8.1 from the native promoter leads to unique cell death lesions and enhances resistance to virulent fungal and oomycete pathogens that cause powdery mildew and downy mildew diseases, respectively. In powdery mildew-infected plants, RPW8.1-YFP accumulates at higher levels in the mesophyll cells underneath the infected epidermal cells where RPW8.2-YFP is mainly expressed. This cell type-preferential protein accumulation pattern largely correlates with that of H(2)O(2) accumulation, suggesting that RPW8.1 may spatially collaborate with RPW8.2 in activation of resistance to powdery mildew. Interestingly, when ectopically expressed from the RPW8.2 promoter, RPW8.1-YFP is also targeted to the EHM of powdery mildew and the transgenic plants display resistance to both powdery mildew and downy mildew. Using YFP as a reporter, we further reveal that the RPW8.1 promoter is constitutively active but induced to higher levels in cells at the infection site, whereas the RPW8.2 promoter is activated specifically in cells at the infection site. Taken together, our results suggest that RPW8.1 (and its promoter) is functionally distinct from RPW8.2 and may have a higher potential in engineering broad-spectrum resistance in plants.
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, ChinaInstitute of Bioscience and Biotechnology Research and Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20850, USAThese authors contributed equally to this work.
authors.forename: Xian-Feng
authors.initials: XF
authors.lastname: Ma
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, ChinaThese authors contributed equally to this work.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, ChinaThese authors contributed equally to this work.
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Sun
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fan
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Huang
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Yong-Ju
authors.initials: YJ
authors.lastname: Xu
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Ji-Qun
authors.initials: JQ
authors.lastname: Zhao
authors.affiliation: Institute of Bioscience and Biotechnology Research and Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20850, USA.
authors.forename: Shunyuan
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, ChinaInstitute of Bioscience and Biotechnology Research and Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20850, USA j316wenmingwang@sicau.edu.cn.
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001203:Ascomycota / Q000502:physiology*; D016923:Cell Death; D060467:Disease Resistance; D015870:Gene Expression; D017930:Genes, Reporter; D054884:Host-Pathogen Interactions; D058503:Mesophyll Cells; D009868:Oomycetes / Q000502:physiology*; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C418462:RPW8.1 protein, Arabidopsis; D011993:Recombinant Fusion Proteins
keywords: Downy mildew; Epidermal cell; Extrahaustorial membrane; Haustorium; Mesophyll cell; Powdery mildew