Development of 11 Ecklonia radicosa (Phaeophyceae, Laminariales) SSRs markers using next-generation sequencing and intra-genus amplification analysis

Polymorphic simple sequence repeat (SSR) markers of Ecklonia radicosa were developed using Illumina MiSeq next-generation sequencing (NGS) analysis. In total, 3112 SSRs (di- to hexanucleotide motifs repeated more than six times) were identified from 61.5-Mb assembled genomic DNA using MISA perl script. Among the SSRs, di- (853 loci, 27.4%) and trinucleotides (1813 loci, 58.3%) were dominant, while tetra- (172 loci, 5.5%), penta- (175 loci, 5.6%), and hexanucleotides (99 loci, 3.2%) were not common. After specific amplification and polymorphic tests of 75 selected loci (tri- to hexanucleotide motifs repeated more than eight times), 11 SSR markers (Eradic01–11) were successfully developed. The range of the number of alleles, observed heterozygosity, and expected heterozygosity in the 11 markers was 3–13, 0.200–0.683, and 0.258–0.864, respectively. Polymorphic information content (PIC) analysis indicated that eight markers (Eradic01, 02, 04, 05, 06, 08, 09, and 11) were highly informative (PIC > 0.5) and the other three were reasonably informative (0.5 < PIC < 0.25). In addition, intra-genus amplification was obtained in all markers except for Eradic02, 08, and 11. These markers could help to reveal the genetic diversity and population structure of E. radicosa.