title: Genetic diversity of Crotalaria germplasm assessed through phylogenetic analysis of EST-SSR markers.
abstract: The genetic diversity of the genus Crotalaria is unknown even though many species in this genus are economically valuable. We report the first study in which polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers derived from Medicago and soybean were used to assess the genetic diversity of the Crotalaria germplasm collection. This collection consisted of 26 accessions representing 4 morphologically characterized species. Phylogenetic analysis partitioned accessions into 4 main groups generally along species lines and revealed that 2 accessions were incorrectly identified as Crotalaria juncea and Crotalaria spectabilis instead of Crotalaria retusa. Morphological re-examination confirmed that these 2 accessions were misclassified during curation or conservation and were indeed C. retusa. Some amplicons from Crotalaria were sequenced and their sequences showed a high similarity (89% sequence identity) to Medicago truncatula from which the EST-SSR primers were designed; however, the SSRs were completely deleted in Crotalaria. Highly distinguishing markers or more sequences are required to further classify accessions within C. juncea.
authors.affiliation: USDA-ARS, PGRCU, 1109 Experiment Street, Griffin, GA 30223, USA. mwang@ars-grin.gov
authors.forename: M L
authors.initials: ML
authors.lastname: Wang
authors.forename: J A
authors.initials: JA
authors.lastname: Mosjidis
authors.forename: J B
authors.initials: JB
authors.lastname: Morris
authors.forename: R E
authors.initials: RE
authors.lastname: Dean
authors.forename: T M
authors.initials: TM
authors.lastname: Jenkins
authors.forename: G A
authors.initials: GA
authors.lastname: Pederson
mesh_terms: D001483:Base Sequence; D029864:Crotalaria / Q000235:genetics*; D030541:Databases, Genetic; D020224:Expressed Sequence Tags; D005819:Genetic Markers; D014644:Genetic Variation; D018745:Genome, Plant; D018598:Minisatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D035261:Plant Components, Aerial / Q000033:anatomy & histology; D012639:Seeds / Q000033:anatomy & histology; D012689:Sequence Homology, Nucleic Acid
chemical_list: D005819:Genetic Markers