title: Development, polymorphism, and cross-taxon utility of EST-SSR markers from safflower (Carthamus tinctorius L.).
abstract: Due to their highly polymorphic and codominant nature, simple-sequence repeat (SSR) markers are a common choice for assaying genetic diversity and genetic mapping. In this paper, we describe the generation of an expressed-sequence tag (EST) collection for the oilseed crop safflower and the subsequent development of EST-SSR markers for the genetic analysis of safflower and related species. We assembled 40,874 reads into 19,395 unigenes, of which 4,416 (22.8%) contained at least one SSR. Primer pairs were developed and tested for 384 of these loci, resulting in a collection of 104 polymorphic markers that amplify reliably across 27 accessions (3 species) of the genus Carthamus. These markers exhibited a high level of polymorphism, with an average of 6.0 +/- 0.4 alleles per locus and an average gene diversity of 0.54 +/- 0.03 across Carthamus species. In terms of cross-taxon transferability, 50% of these primer pairs produced an amplicon in at least one other species in the Asteraceae, and 28% produced an amplicon in at least one species outside the safflower subfamily (i.e., lettuce, sunflower, and/or Gerbera). These markers represent a valuable resource for the genetic analysis of safflower and related species, and also have the potential to facilitate comparative map-based analyses across a broader array of taxa within the Asteraceae.
authors.affiliation: Department of Plant Biology, University of Georgia, Miller Plant Sciences Building, Athens, GA 30602, USA. mchapman@plantbio.uga.edu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Chapman
authors.forename: John
authors.initials: J
authors.lastname: Hvala
authors.forename: Jason
authors.initials: J
authors.lastname: Strever
authors.forename: Marta
authors.initials: M
authors.lastname: Matvienko
authors.forename: Alexander
authors.initials: A
authors.lastname: Kozik
authors.forename: Richard W
authors.initials: RW
authors.lastname: Michelmore
authors.forename: Shunxue
authors.initials: S
authors.lastname: Tang
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Knapp
authors.forename: John M
authors.initials: JM
authors.lastname: Burke
mesh_terms: D031187:Carthamus tinctorius / Q000145:classification* / Q000235:genetics*; D020224:Expressed Sequence Tags; D015723:Gene Library; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic