title: Molecular characterization of durum and common wheat recombinant lines carrying leaf rust resistance (Lr19) and yellow pigment (Y) genes from Lophopyrum ponticum.
abstract: Chromosome 7E from Lophopyrum ponticum carries a valuable leaf rust resistant gene designated Lr19. This gene has not been widely used in common wheat breeding because of linkage with the yellow pigment gene Y. This gene tints flour yellow, reducing its appeal in bread making. However, a high level of yellow pigment is desirable in durum wheat breeding. We produced 97 recombinant chromosomes between L. ponticum transfer 7D.7E#1 and its wheat homoeologues, using the ph1b mutation that promotes homoeologous pairing. We characterized a subset of 37 of these lines with 11 molecular markers and evaluated their resistance to leaf rust and the abundance of yellow pigment. The Lr19 gene was mapped between loci Xwg420 and Xmwg2062, whereas Y was mapped distal to Xpsr687, the most distal marker on the long arm of chromosome 7. A short terminal 7EL segment translocated to 7A, including Lr19 and Y (line 1-23), has been transferred to durum wheat by backcrossing. The presence of this alien segment significantly increased the abundance of yellow pigment. The Lr19 also conferred resistance to a new durum leaf rust race from California and Mexico that is virulent on most durum wheat cultivars. The new durum lines with the recombinant 7E segment will be useful parents to increase yellow pigment and leaf rust resistance in durum wheat breeding programs. For the common wheat breeding programs, we selected the recombinant line 1-96, which has an interstitial 7E segment carrying Lr19 but not Y. This recombinant line can be used to improve leaf rust resistance without affecting flour color. The 7EL/7DL 1-96 recombinant chromosome did not show the meiotic self-elimination previously reported for a 7EL/7BL translocation.
authors.affiliation: Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Lukaszewski
authors.forename: Jim
authors.initials: J
authors.lastname: Kolmer
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Soria
authors.forename: Sham
authors.initials: S
authors.lastname: Goyal
authors.forename: Jorge
authors.initials: J
authors.lastname: Dubcovsky
mesh_terms: D001487:Basidiomycota / Q000472:pathogenicity*; D002851:Chromatography, High Pressure Liquid; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D003433:Crosses, Genetic; D018744:DNA, Plant; D017343:Genes, Plant / Q000276:immunology*; D005819:Genetic Markers; D007113:Immunity, Innate; D010860:Pigments, Biological; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D006109:Poaceae / Q000235:genetics*; D016133:Polymerase Chain Reaction; D019105:Random Amplified Polymorphic DNA Technique; D013045:Species Specificity; D014908:Triticum / Q000145:classification / Q000235:genetics* / Q000382:microbiology
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers; D010860:Pigments, Biological