title: Genotype-by-sequencing facilitates genetic mapping of a stem rust resistance locus in Aegilops umbellulata, a wild relative of cultivated wheat.
abstract: Wild relatives of wheat play a significant role in wheat improvement as a source of genetic diversity. Stem rust disease of wheat causes significant yield losses at the global level and stem rust pathogen race TTKSK (Ug99) is virulent to most previously deployed resistance genes. Therefore, the objective of this study was to identify loci conferring resistance to stem rust pathogen races including Ug99 in an Aegilops umbelluata bi-parental mapping population using genotype-by-sequencing (GBS) SNP markers.
  
  
  
  A bi-parental F2:3population derived from a cross made between stem rust resistant accession PI 298905 and stem rust susceptible accession PI 542369 was used for this study. F2individuals were evaluated with stem rust race TTTTF followed by testing F2:3families with races TTTTF and TTKSK. The segregation pattern of resistance to both stem rust races suggested the presence of one resistance gene. A genetic linkage map, comprised 1,933 SNP markers, was created for all seven chromosomes of Ae. umbellulata using GBS. A major stem rust resistance QTL that explained 80% and 52% of the phenotypic variations for TTTTF and TTKSK, respectively, was detected on chromosome 2U of Ae. umbellulata.
  
  
  
  The novel resistance gene for stem rust identified in this study can be transferred to commercial wheat varieties assisted by the tightly linked markers identified here. These markers identified through our mapping approach can be a useful strategy to identify and track the resistance gene in marker-assisted breeding in wheat.
authors.affiliation: USDA-ARS, Cereal Disease Laboratory, St. Paul, MN, 55108, USA. erena.edae@ars.usda.gov.
authors.forename: Erena A
authors.initials: EA
authors.lastname: Edae
authors.affiliation: Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: Pablo D
authors.initials: PD
authors.lastname: Olivera
authors.affiliation: USDA-ARS, Cereal Disease Laboratory, St. Paul, MN, 55108, USA.|Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Wheat Genetics Resource Center, Department of Plant Pathology and Department of Agronomy, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Jesse A
authors.initials: JA
authors.lastname: Poland
authors.affiliation: USDA-ARS, Cereal Disease Laboratory, St. Paul, MN, 55108, USA. matthew.rouse@ars.usda.gov.|Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA. matthew.rouse@ars.usda.gov.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Rouse
mesh_terms: D001947:Breeding; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D008040:Genetic Linkage; D018745:Genome, Plant; D005838:Genotype; D008126:Lod Score; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D014908:Triticum / Q000235:genetics*
keywords: Aegilops umbellulata; GBS; High density linkage map; Stem rest resistance; Wild relatives