title: Natural genetic resources of Arabidopsis thaliana reveal a high prevalence and unexpected phenotypic plasticity of RPW8-mediated powdery mildew resistance.
abstract: Here, an approach based on natural genetic variation was adopted to analyse powdery mildew resistance in Arabidopsis thaliana. Accessions resistant to multiple powdery mildew species were crossed with the susceptible Col-0 ecotype and inheritance of resistance was analysed. Histochemical staining was used to visualize archetypal plant defence responses such as callose deposition, hydrogen peroxide accumulation and host cell death in a subset of these ecotypes. In six accessions, resistance was likely of polygenic origin while 10 accessions exhibited evidence for a single recessively or semi-dominantly inherited resistance locus. Resistance in the latter accessions was mainly manifested at the terminal stage of the fungal life cycle by a failure of abundant conidiophore production. The resistance locus of several of these ecotypes was mapped to a genomic region containing the previously analysed atypical RPW8 powdery mildew resistance genes. Gene silencing revealed that members of the RPW8 locus were responsible for resistance to Golovinomyces orontii in seven accessions. These results suggest that broad-spectrum powdery mildew resistance in A. thaliana is predominantly of polygenic origin or based on RPW8 function. The findings shed new light on the natural variation of inheritance, phenotypic expression and pathogen range of RPW8-conditioned powdery mildew resistance.
authors.affiliation: Max-Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Göllner
authors.affiliation: Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Department of Cytogenetics and Transcriptome Analysis, Corrensstraße 3, 06466 Gatersleben, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Schweizer
authors.affiliation: Laboratory of Plant Breeding, Plant Sciences Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Max-Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Panstruga
mesh_terms: D017360:Arabidopsis / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001203:Ascomycota / Q000276:immunology*; D016923:Cell Death / Q000276:immunology; D002874:Chromosome Mapping; D005816:Genetic Complementation Test; D014644:Genetic Variation; D005936:Glucans / Q000378:metabolism; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology*; D007113:Immunity, Innate / Q000235:genetics; D008853:Microscopy; D020412:Multifactorial Inheritance; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005936:Glucans; C418462:RPW8.1 protein, Arabidopsis; C418463:RPW8.2 protein, Arabidopsis; D017382:Reactive Oxygen Species; C048306:callose