Identification of management units in threatened populations of Arnica mallotopus Makino (Asteraceae) using novel EST-SSR markers.

Arnica mallotopus is a perennial herb endemic to the snowy regions of Japan. At the southern edge of its distribution, in Kyoto Prefecture, overgrazing by sika deer and decreased snowfall have resulted in the rapid decline of A. mallotopus populations. Therefore, there is an urgent need for a conservation genetic analysis of the remaining local populations. In this study, we first developed 13 EST-SSR markers to evaluate genetic variation in A. mallotopus. The average number of alleles per locus was 5.33. Genetic analysis using these markers showed that the investigated samples were classified into two groups corresponding to landscape structure. One group isolated from a tributary of the Yura River showed a strong population bottleneck signal, likely resulting from founder effects and subsequent drifts. On the other hand, the genetic diversity of the second group in the main distribution along the Yura River was higher and less inbred. Overall, our assessment suggested recognizing the two genetic groups as management units in conservation programs for the threatened populations.

Development of nuclear SSRs for the insular shrub Clerodendrum izuinsulare (Verbenaceae) and the widespread C. trichotomum.

PREMISE OF THE STUDY: Nuclear microsatellite primers were developed in the insular shrub Clerodendrum izuinsulare and the closely related widespread C. trichotomum to provide molecular tools to undertake a comparative study of the reproductive systems and genetic structures of the two Clerodendrum species. METHODS AND RESULTS: Using an improved protocol for isolating codominant compound microsatellite markers, 19 primer sets were developed in C. izuinsulare and C. trichotomum. The primers amplified dinucleotide repeats with one to nine alleles per locus in C. izuinsulare and one to 15 alleles per locus in C. trichotomum. Tests of cross-amplification showed that four to 16 loci could be amplified using these markers in five other species of Clerodendrum that were studied. CONCLUSIONS: The microsatellite markers described here will be useful for comparative study of the reproductive systems and genetic structures of the narrow endemic C. izuinsulare and the widespread C. trichotomum.