Development of SSR markers for Psychotria homalosperma (Rubiaceae) and cross-amplification in four other species(1)

PREMISE OF THE STUDY: Twenty-six microsatellite (simple sequence repeat [SSR]) markers were characterized in Psychotria homalosperma (Rubiaceae), an endemic evergreen tree in the Bonin Islands, Japan, to investigate the genetic structure and gene flow of the species. METHODS AND RESULTS: Using next-generation sequencing, we developed 26 SSR markers for P. homalosperma with perfect motifs from di- to pentanucleotide repeats. Of these, the Chichijima and Hahajima island populations of P. homalosperma had mean allele numbers of 6.50 and 6.81, respectively. The mean expected heterozygosities were 0.578 and 0.606, respectively. In addition, 10 and eight of these markers were successfully amplified for P. boninensis and P. serpens, respectively, occurring in the same or adjacent areas. CONCLUSIONS: The SSR markers developed in this study will be useful for future studies concerning the population genetics of P. homalosperma and will facilitate the development of a conservation strategy.