Genome size and SCoT markers as tools for identification and genetic diversity assessment in Echinacea genus

The Echinacea (coneflower) genus includes herbaceous flowering species mainly used for medicinal purposes, as well as the ornamental plants. Morphological similarities between Echinacea species often lead to their incorrect identification and characterization. Genome size and SCoT markers were used for identification and establishing the taxonomic relationships within Echinacea genus. The analysis of the nuclear DNA content indicated, that the majority of Echinacea species possessed intermediate genomes, and only E. pallida has a large genome size. 2C DNA content ranged from 14.31 pg/2C (E. simulata) to 28.59 pg/2C (E. pallida). Based on flow cytometric measurements (FCM) of the nuclear DNA content it was possible to distinguish three coneflower species, E. simulata, E. pallida and E. sanguinea, confirming validity of the method for initial species identification. Whereas, SCoT-PCR analysis enabled the identification of all studied accessions. Nine primers revealed polymorphism both between species, as well as varieties of E. angustifolia and E. paradoxa, demonstrating the usefulness of SCoT primers for genetic diversity studies in this genus. The phylogenetic analysis confirmed, that Echinacea species are closely related and within the investigated accessions two main phylogenetic groups exist, with one species (E. purpurea) being not clustered to any of the groups. Two methods, FCM and SCoT-PCR, can be successfully applied in identification and taxonomic relationship assessment, as well as in determination of the genetic diversity of Echinacea genus. Moreover, this is the first report on genome size that includes eight Echinacea accessions.