Development of Saccharina japonica genomic SSR markers using next-generation sequencing

Illumina HiSeq 2000 next-generation sequencing (NGS) was used on Saccharina japonica specimens to develop SSRs from high-quality genomic sequences. There were 181,595 SSR loci identified using the MISA program. SSR repeat types are plentiful in genomic sequences of S. japonica, with the most abundant types being mononucleotides (54 %) and trinucleotides (26 %). Six hundred primer pairs were selected and synthesized from 19,658 primer pairs, showing 166 polymorphic SSR loci (28 %) in three selected S. japonica individuals. Sixty polymorphic SSRs were further analyzed in 24 S. japonica individuals, showing two to seven alleles for each locus (average 3.7 alleles), with observed heterozygosities of 0 similar to 0.625 and expected heterozygosities of 0.082 similar to 0.745. Polymorphism information content (PIC) values ranged from 0.08 to 0.69. Sixteen loci were classified as informative markers (PIC > 0.5). Polymorphic SSR markers developed in this study should be useful for examining genetic diversity, assessment of population structure, QTL mapping, and marker-assisted selection in S. japonica.