title: Physical mapping of DNA markers linked to stem rust resistance gene Sr47 in durum wheat.
abstract: Markers linked to stem rust resistance gene Sr47 were physically mapped in three small Aegilops speltoides chromosomal bins. Five markers, including two PCR-based SNP markers, were validated for marker-assisted selection. In durum wheat (Triticum turgidum subsp. durum), the gene Sr47 derived from Aegilops speltoides conditions resistance to race TTKSK (Ug99) of the stem rust pathogen (Puccinia graminis f. sp. tritici). Sr47 is carried on small interstitial translocation chromosomes (Ti2BL-2SL-2BL·2BS) in which the Ae. speltoides chromosome 2S segments are divided into four bins in genetic stocks RWG35, RWG36, and RWG37. Our objective was to physically map molecular markers to bins and to determine if any of the molecular markers would be useful in marker-assisted selection (MAS). Durum cultivar Joppa was used as the recurrent parent to produce three BC2F2populations. Each BC2F2plant was genotyped with markers to detect the segment carrying Sr47, and stem rust testing of BC2F3progeny with race TTKSK confirmed the genotyping. Forty-nine markers from published sources, four new SSR markers, and five new STARP (semi-thermal asymmetric reverse PCR) markers, were evaluated in BC2F2populations for assignment of markers to bins. Sr47 was mapped to bin 3 along with 13 markers. No markers were assigned to bin 1; however, 7 and 13 markers were assigned to bins 2 and 4, respectively. Markers Xrwgs38a, Xmag1729, Xwmc41, Xtnac3119, Xrwgsnp1, and Xrwgsnp4 were found to be useful for MAS of Sr47. However, STARP markers Xrwgsnp1 and Xrwgsnp4 can be used in gel-free systems, and are the preferred markers for high-throughput MAS. The physical mapping data from this study will also be useful for pyramiding Sr47 with other Sr genes on chromosome 2B.
authors.affiliation: USDA-ARS, Northern Crop Science Laboratory, Cereal Crops Research Unit, Red River Valley Agricultural Research Center, 1605 Albrecht Blvd. North, Fargo, ND, 58102-2765, USA.
authors.forename: Daryl L
authors.initials: DL
authors.lastname: Klindworth
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Saini
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA.
authors.forename: Yunming
authors.initials: Y
authors.lastname: Long
authors.affiliation: USDA-ARS, Cereal Disease Laboratory, and Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Rouse
authors.affiliation: USDA-ARS, Northern Crop Science Laboratory, Cereal Crops Research Unit, Red River Valley Agricultural Research Center, 1605 Albrecht Blvd. North, Fargo, ND, 58102-2765, USA.
authors.forename: Justin D
authors.initials: JD
authors.lastname: Faris
authors.affiliation: USDA-ARS, Cereal Disease Laboratory, and Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Jin
authors.affiliation: USDA-ARS, Northern Crop Science Laboratory, Cereal Crops Research Unit, Red River Valley Agricultural Research Center, 1605 Albrecht Blvd. North, Fargo, ND, 58102-2765, USA. steven.xu@ars.usda.gov.
authors.forename: Steven S
authors.identifier: http://orcid.org/0000-0001-7000-2034
authors.initials: SS
authors.lastname: Xu
mesh_terms: D001487:Basidiomycota; D002874:Chromosome Mapping; D018744:DNA, Plant / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D005819:Genetic Markers; D005838:Genotype; D018895:Microsatellite Repeats; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D006109:Poaceae / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D014908:Triticum / Q000235:genetics* / Q000382:microbiology
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers