title: Combined linkage and association mapping reveals candidates for Scmv1, a major locus involved in resistance to sugarcane mosaic virus (SCMV) in maize.
abstract: BACKGROUND
  Sugarcane mosaic virus (SCMV) disease causes substantial losses of grain yield and forage biomass in susceptible maize cultivars. Maize resistance to SCMV is associated with two dominant genes, Scmv1 and Scmv2, which are located on the short arm of chromosome 6 and near the centromere region of chromosome 3, respectively. We combined both linkage and association mapping to identify positional candidate genes for Scmv1.
  
  
  RESULTS
  Scmv1 was fine-mapped in a segregating population derived from near-isogenic lines and further validated and fine-mapped using two recombinant inbred line populations. The combined results assigned the Scmv1 locus to a 59.21-kb interval, and candidate genes within this region were predicted based on the publicly available B73 sequence. None of three predicted genes that are possibly involved in the disease resistance response are similar to receptor-like resistance genes. Candidate gene-based association mapping was conducted using a panel of 94 inbred lines with variable resistance to SCMV. A presence/absence variation (PAV) in the Scmv1 region and two polymorphic sites around the Zmtrx-h gene were significantly associated with SCMV resistance.
  
  
  CONCLUSIONS
  Combined linkage and association mapping pinpoints Zmtrx-h as the most likely positional candidate gene for Scmv1. These results pave the way towards cloning of Scmv1 and facilitate marker-assisted selection for potyvirus resistance in maize.
authors.forename: Yongfu
authors.initials: Y
authors.lastname: Tao
authors.forename: Lu
authors.initials: L
authors.lastname: Jiang
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Christina Roenn
authors.initials: CR
authors.lastname: Ingvardsen
authors.forename: Ursula Karoline
authors.initials: UK
authors.lastname: Frei
authors.forename: Baobao
authors.initials: B
authors.lastname: Wang
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Lai
authors.forename: Thomas
authors.initials: T
authors.lastname: Lübberstedt
authors.affiliation: National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100193, People's Republic of China. mxu@cau.edu.cn.
authors.forename: Mingliang
authors.initials: M
authors.lastname: Xu
mesh_terms: D002874:Chromosome Mapping / Q000379:methods*; D003433:Crosses, Genetic; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics; D056726:Genetic Association Studies; D008040:Genetic Linkage; D056426:Genetic Loci / Q000235:genetics*; D005819:Genetic Markers; D005828:Genetics, Population; D007178:Inbreeding; D015810:Linkage Disequilibrium / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D009029:Mosaic Viruses / Q000502:physiology*; D020161:Physical Chromosome Mapping; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D015203:Reproducibility of Results; D031786:Saccharum / Q000821:virology; D003313:Zea mays / Q000235:genetics* / Q000821:virology*
chemical_list: D005819:Genetic Markers