Isolation and characterization of microsatellite loci for the Potentilla core group (Rosaceae) using 454 sequencing.

Microsatellites are valuable markers for the analysis of genetic diversity, linkage mapping or genotyping. The limited availability of microsatellites for the genus Potentilla (Rosaceae) stipulated the isolation of markers from a representative (Potentilla pusilla Host) of the Potentilla core group that constitutes the most species-rich evolutionary lineage within the genus. Thousand four hundred and seventy-six simple sequence repeat (SSR) containing candidate sequences were isolated from a single-type line using 454 sequencing. Seventy-four functional microsatellite markers were developed from 200 sequences selected for suitable priming sites flanking microsatellite repeats referring to a 37% primer-to-marker conversion ratio. Seventy-two markers were polymorphic. These numbers confirm the increased efficiency of pyrosequencing over traditional isolation techniques in the development of microsatellites. Amplification primer sequences and the sequences of corresponding target fragments are provided for all functional markers, and molecular polymorphisms estimated for four accessions of P. pusilla and among seven core group species represented by 14 individuals are reported. Cross-species transferability ranged between 86.4% and 97.3% among the studied taxa, and 57, 11 and six of the selected primer pairs amplified fragments of expected size and number in seven, six and five of the species, respectively. Reproducibility of the molecular phenotypes was 97.0%, which was inferred using a replicate sample of P. pusilla.