Chloroplast Genome-Based Hypervariable Markers for Rapid Authentication of Six Korean Pyropia Species

Abstract

We previously established that polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using partial plastid rbcL and mitochondrial trnC–trnP gene sequences can be used to distinguish the six representative Pyropia species produced via mariculture in Korea. In this study, we develop progressive InDel markers by comparing seven complete Pyropia chloroplast genomes obtained from The National Center of Biotechnology Informnation (NCBI) GenBank. Comparative analyses of nucleotide diversity among the genomes revealed seven hypervariable sites (cemA, rps13, trnM-argB, petD-petB, trnR-trnQ, ccs1-orf24, and ycf12-ftrB) among 637 sliding windows with nucleotide diversity > 0.025 (Pi). These sites included two genes and five gene-intergenic regions, three of which (cemA, trnM-argB, trnR-trnQ) showed complete amplification for all six test species. Finally, trnM-argB, an InDel-variable locus with high discriminatory power, was selected as a DNA barcode candidate. These results suggest that the obtained trnM-argB region can be used for the effective exploration of the variation present in six Korean Pyropia and for further evolutionary, phylogenetic, barcoding and genetic engineering studies of Pyropia species.