title: Genetic dissection of a TIR-NB-LRR locus from the wild North American grapevine species Muscadinia rotundifolia identifies paralogous genes conferring resistance to major fungal and oomycete pathogens in cultivated grapevine.
abstract: The most economically important diseases of grapevine cultivation worldwide are caused by the fungal pathogen powdery mildew (Erysiphe necator syn. Uncinula necator) and the oomycete pathogen downy mildew (Plasmopara viticola). Currently, grapegrowers rely heavily on the use of agrochemicals to minimize the potentially devastating impact of these pathogens on grape yield and quality. The wild North American grapevine species Muscadinia rotundifolia was recognized as early as 1889 to be resistant to both powdery and downy mildew. We have now mapped resistance to these two mildew pathogens in M. rotundifolia to a single locus on chromosome 12 that contains a family of seven TIR-NB-LRR genes. We further demonstrate that two highly homologous (86% amino acid identity) members of this gene family confer strong resistance to these unrelated pathogens following genetic transformation into susceptible Vitis vinifera winegrape cultivars. These two genes, designated resistance to Uncinula necator (MrRUN1) and resistance to Plasmopara viticola (MrRPV1) are the first resistance genes to be cloned from a grapevine species. Both MrRUN1 and MrRPV1 were found to confer resistance to multiple powdery and downy mildew isolates from France, North America and Australia; however, a single powdery mildew isolate collected from the south-eastern region of North America, to which M. rotundifolia is native, was capable of breaking MrRUN1-mediated resistance. Comparisons of gene organization and coding sequences between M. rotundifolia and the cultivated grapevine V. vinifera at the MrRUN1/MrRPV1 locus revealed a high level of synteny, suggesting that the TIR-NB-LRR genes at this locus share a common ancestor.
authors.affiliation: CSIRO Plant Industry, PO Box 350, Glen Osmond, SA, 5064, Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: Feechan
authors.forename: Claire
authors.initials: C
authors.lastname: Anderson
authors.forename: Laurent
authors.initials: L
authors.lastname: Torregrosa
authors.forename: Angelica
authors.initials: A
authors.lastname: Jermakow
authors.forename: Pere
authors.initials: P
authors.lastname: Mestre
authors.forename: Sabine
authors.initials: S
authors.lastname: Wiedemann-Merdinoglu
authors.forename: Didier
authors.initials: D
authors.lastname: Merdinoglu
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Walker
authors.forename: Lance
authors.initials: L
authors.lastname: Cadle-Davidson
authors.forename: Bruce
authors.initials: B
authors.lastname: Reisch
authors.forename: Sebastien
authors.initials: S
authors.lastname: Aubourg
authors.forename: Nadia
authors.initials: N
authors.lastname: Bentahar
authors.forename: Bipna
authors.initials: B
authors.lastname: Shrestha
authors.forename: Alain
authors.initials: A
authors.lastname: Bouquet
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Adam-Blondon
authors.forename: Mark R
authors.initials: MR
authors.lastname: Thomas
authors.forename: Ian B
authors.initials: IB
authors.lastname: Dry
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D001203:Ascomycota / Q000235:genetics / Q000276:immunology*; D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics / Q000276:immunology; D017343:Genes, Plant; D009868:Oomycetes / Q000235:genetics / Q000276:immunology*; D057865:Plant Immunity / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics*; D027844:Vitaceae / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
chemical_list: D010940:Plant Proteins
keywords: Erysiphe necator; Muscadinia rotundifolia; Plasmopora viticola; Vitis vinifera; downy mildew; grapevine; powdery mildew; resistance