title: SNP-based codominant markers for a recessive gene conferring resistance to corky root rot (Rhizomonas suberifaciens) in lettuce (Lactuca sativa).
abstract: The analysis of F2 progeny and derived F3 families of Lactuca sativa segregating for resistance to corky root rot caused by Rhizomonas suberifaciens permitted the identification of restriction fragment length polymorphism (RFLP) and single nucleotide polymorphism (SNP) markers linked to the recessive resistance gene cor. PCR-based markers were identified by bulked segregant analysis (BSA). Allele-specific primers were generally designed with the 3 terminal base coinciding with an SNP, matching one of the alleles and mismatching the other, and with an additional subterminal 3 base mismatching both alleles. Codominant, robust, and inexpensive molecular markers were obtained that used standardized PCR conditions. Some of the markers could be analyzed in multiple Lactuca mapping populations that did not segregate for disease resistance allowing the cor locus to be located on several maps. The consistent low density of markers around cor in these maps suggests that cor may be in an area with an elevated rate of recombination. Evaluation of these markers in a large sample of cultivars and landraces identified pairs of flanking polymorphic markers that can be used for marker-assisted selection of corky root resistance.
authors.affiliation: Departamento de Biología Vegetal, E.T.S. Ingenieros Agrónomos, Universidad Poltécnica de Madrid, Ciudad Universitaria, Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Moreno-Vázquez
authors.forename: Oswaldo E
authors.initials: OE
authors.lastname: Ochoa
authors.forename: Nanne
authors.initials: N
authors.lastname: Faber
authors.forename: Shiaoman
authors.initials: S
authors.lastname: Chao
authors.forename: Jeanne M E
authors.initials: JM
authors.lastname: Jacobs
authors.forename: Brigitte
authors.initials: B
authors.lastname: Maisonneuve
authors.forename: Richard V
authors.initials: RV
authors.lastname: Kesseli
authors.forename: Richard W
authors.initials: RW
authors.lastname: Michelmore
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D005787:Gene Frequency; D005819:Genetic Markers / Q000235:genetics*; D006090:Gram-Negative Bacteria / Q000254:growth & development*; D007113:Immunity, Innate / Q000235:genetics; D018545:Lactuca / Q000235:genetics* / Q000382:microbiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers