Development and multiplexing of the first microsatellite markers in a coralline red alga (Phymatolithon calcareum, Rhodophyta)

Coralline red algae are important habitat builders in coastal waters around the world but their population genetics has been largely overlooked because of a lack of appropriate markers. Here, next generation sequencing was used to identify the first set of microsatellite loci ever developed for a coralline alga, Phymatolithon calcareum, a common builder of maerl beds, particularly in Europe. Eleven polymorphic microsatellite markers were identified, of which eight were particularly suitable for population and individual-based applications. In these, the number of alleles ranged from two to five, while expected heterozygosities varied from 0.143 to 0.803. Two multiplex polymerase chain reactions were designed and proved to successfully amplify these loci in specimens collected along the European Atlantic. The new set of markers will enable the study of population genetic diversity and connectivity patterns of these non-geniculate corallines that are especially relevant to propose conservation actions.