title: Transcriptome sequencing of two parental lines of cabbage (Brassica oleracea L. var. capitata L.) and construction of an EST-based genetic map.
abstract: BACKGROUND
  Expressed sequence tag (EST)-based markers are preferred because they reflect transcribed portions of the genome. We report the development of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers derived from transcriptome sequences in cabbage, and their utility for map construction.
  
  
  RESULTS
  Transcriptome sequences were obtained from two cabbage parental lines, C1184 and C1234, which are susceptible and resistant to black rot disease, respectively, using the 454 platform. A total of 92,255 and 127,522 reads were generated and clustered into 34,688 and 40,947 unigenes, respectively. We identified 2,405 SSR motifs from the unigenes of the black rot-resistant parent C1234. Trinucleotide motifs were the most abundant (66.15%) among the repeat motifs. In addition, 1,167 SNPs were detected between the two parental lines. A total of 937 EST-based SSR and 97 SNP-based dCAPS markers were designed and used for detection of polymorphism between parents. Using an F2 population, we built a genetic map comprising 265 loci, and consisting of 98 EST-based SSRs, 21 SNP-based dCAPS, 55 IBP markers derived from B. rapa genome sequence and 91 public SSRs, distributed on nine linkage groups spanning a total of 1,331.88 cM with an average distance of 5.03 cM between adjacent loci. The parental lines used in this study are elite breeding lines with little genetic diversity; therefore, the markers that mapped in our genetic map will have broad spectrum utility.
  
  
  CONCLUSIONS
  This genetic map provides additional genetic information to the existing B. oleracea map. Moreover, the new set of EST-based SSR and dCAPS markers developed herein is a valuable resource for genetic studies and will facilitate cabbage breeding. Additionally, this study demonstrates the usefulness of NGS transcriptomes for the development of genetic maps even with little genetic diversity in the mapping population.
authors.forename: Nur Kholilatul
authors.initials: NK
authors.lastname: Izzah
authors.forename: Jonghoon
authors.initials: J
authors.lastname: Lee
authors.forename: Murukarthick
authors.initials: M
authors.lastname: Jayakodi
authors.forename: Sampath
authors.initials: S
authors.lastname: Perumal
authors.forename: Mina
authors.initials: M
authors.lastname: Jin
authors.forename: Beom-Seok
authors.initials: BS
authors.lastname: Park
authors.forename: Kyounggu
authors.initials: K
authors.lastname: Ahn
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea. tjyang@snu.ac.kr.
authors.forename: Tae-Jin
authors.initials: TJ
authors.lastname: Yang
mesh_terms: D001937:Brassica / Q000235:genetics*; D002874:Chromosome Mapping; D019295:Computational Biology / Q000379:methods*; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D008040:Genetic Linkage; D005819:Genetic Markers; D059014:High-Throughput Nucleotide Sequencing; D018895:Microsatellite Repeats; D058977:Molecular Sequence Annotation; D011110:Polymorphism, Genetic; D059467:Transcriptome
chemical_list: D005819:Genetic Markers