title: Vitis rupestris B38 Confers Isolate-Specific Quantitative Resistance to Penetration by Erysiphe necator.
abstract: Vitis rupestris B38 is a North American grapevine resistant to the major pathogen of cultivated grapevines, Erysiphe necator. Sources of powdery mildew resistance, like V. rotundifolia, are widely used in grape breeding but are already threatened, even before commercialization, by isolates that can reproduce on Run1 and other rotundifolia-derived breeding lines. Thus, complementary sources of resistance are needed to improve resistance durability. The segregation of foliar powdery mildew severity in an F1 family, derived from a cross of V. rupestris B38×V. vinifera 'Chardonnay', was observed in the field over three growing seasons and in potted vines following single-isolate inoculation. A pattern of continuous variation was observed in every instance. Mechanisms of resistance were analyzed on the resistant and susceptible parent by using microscopy to quantify the ability of the pathogen to penetrate and to form a colony on detached leaves. While 'Chardonnay' was susceptible in all tested conditions, V. rupestris B38 resistance was characterized by a reduction in pathogen penetration, with an effect of leaf position and significant differences among powdery mildew isolates. Segregation of the ability of the pathogen to penetrate and form a colony in F1 individuals showed a pattern of quantitative penetration resistance with no delay or restriction on colony formation once penetration has been achieved. Moreover, V. rupestris B38 showed an enhanced penetration resistance to a powdery mildew isolate with the ability to overcome the Run1 gene, making it an interesting resistance source to prolong the durability of this gene.
authors.affiliation: First author: Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second and third authors: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Grape Genetics Research Unit, Geneva, NY 14456; and fourth author: Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456.
authors.forename: Paola
authors.initials: P
authors.lastname: Barba
authors.affiliation: First author: Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second and third authors: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Grape Genetics Research Unit, Geneva, NY 14456; and fourth author: Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456.
authors.forename: Lance
authors.initials: L
authors.lastname: Cadle-Davidson
authors.affiliation: First author: Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second and third authors: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Grape Genetics Research Unit, Geneva, NY 14456; and fourth author: Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456.
authors.forename: Erin
authors.initials: E
authors.lastname: Galarneau
authors.affiliation: First author: Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second and third authors: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Grape Genetics Research Unit, Geneva, NY 14456; and fourth author: Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456.
authors.forename: Bruce
authors.initials: B
authors.lastname: Reisch
mesh_terms: D001203:Ascomycota / Q000502:physiology*; D001947:Breeding; D060467:Disease Resistance / Q000235:genetics*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics; D013045:Species Specificity; D027843:Vitis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology
chemical_list: D010940:Plant Proteins