Microsatellite loci for the host-generalist zooxanthella Symbiodinium trenchi and other Clade D Symbiodinium

Nine new polymorphic microsatellites were developed for Symbiodinium trenchi (sensu type D1a). These loci were tested on populations of S. trenchi from corals in Palau and 3-19 alleles were observed at each haploid locus with an average of 7 alleles. Many of the primer sets successfully amplified loci within other members of Symbiodinium clade D, demonstrating their utility across the group. Clade D Symbiodinium spp. are generally regarded as thermally tolerant and are common in coral reef habitats with warm, turbid, and/or variable environmental conditions. These population genetic markers are therefore useful for investigating how stress-tolerant symbionts may respond to climate warming through range expansion and/or by developing new associations with various host cnidarians. Additionally, the cross-lineage utility of these markers should help delineate the evolutionary relationships among members of this clade.