title: Transgenic Pm3 multilines of wheat show increased powdery mildew resistance in the field.
abstract: Resistance (R) genes protect plants very effectively from disease, but many of them are rapidly overcome when present in widely grown cultivars. To overcome this lack of durability, strategies that increase host resistance diversity have been proposed. Among them is the use of multilines composed of near-isogenic lines (NILs) containing different disease resistance genes. In contrast to classical R-gene introgression by recurrent backcrossing, a transgenic approach allows the development of lines with identical genetic background, differing only in a single R gene. We have used alleles of the resistance locus Pm3 in wheat, conferring race-specific resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici), to develop transgenic wheat lines overexpressing Pm3a, Pm3c, Pm3d, Pm3f or Pm3g. In field experiments, all tested transgenic lines were significantly more resistant than their respective nontransformed sister lines. The resistance level of the transgenic Pm3 lines was determined mainly by the frequency of virulence to the particular Pm3 allele in the powdery mildew population, Pm3 expression levels and most likely also allele-specific properties. We created six two-way multilines by mixing seeds of the parental line Bobwhite and transgenic Pm3a, Pm3b and Pm3d lines. The Pm3 multilines were more resistant than their components when tested in the field. This demonstrates that the difference in a single R gene is sufficient to cause host-diversity effects and that multilines of transgenic Pm3 wheat lines represent a promising strategy for an effective and sustainable use of Pm3 alleles.
authors.affiliation: Institute of Plant Biology, University of Zürich, Zürich, Switzerland Department of Biology, Plant Biotechnology, ETH Zürich, Zürich, Switzerland.
authors.forename: Susanne
authors.initials: S
authors.lastname: Brunner
authors.forename: Daniel
authors.initials: D
authors.lastname: Stirnweis
authors.forename: Carolina
authors.initials: C
authors.lastname: Diaz Quijano
authors.forename: Gabriele
authors.initials: G
authors.lastname: Buesing
authors.forename: Gerhard
authors.initials: G
authors.lastname: Herren
authors.forename: Francis
authors.initials: F
authors.lastname: Parlange
authors.forename: Pierre
authors.initials: P
authors.lastname: Barret
authors.forename: Caroline
authors.initials: C
authors.lastname: Tassy
authors.forename: Christof
authors.initials: C
authors.lastname: Sautter
authors.forename: Michael
authors.initials: M
authors.lastname: Winzeler
authors.forename: Beat
authors.initials: B
authors.lastname: Keller
mesh_terms: D000483:Alleles; D001203:Ascomycota / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D057865:Plant Immunity / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D019076:Transgenes / Q000235:genetics; D014908:Triticum / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000382:microbiology*; D014774:Virulence / Q000235:genetics
chemical_list: D010940:Plant Proteins