Development of organelle single nucleotide polymorphism (SNP) markers and their application for the identification of cytoplasmic inheritance patterns in Pyropia yezoensis (Bangiales, Rhodophyta)

The genus Pyropia contains several important cultivated species. Genetic research in nori species has mainly focused on the cell nucleus, with few studies on organelles (chloroplast and mitochondria). Due to the high copy numbers of organelles in cells, which influence the development and traits of algae, it is necessary to study their genetic mechanism. In this study, the marine red alga Pyropia yezoensis, an important economic macroalga, was selected as the study object. To investigate organelle (chloroplast and mitochondria) inheritance in P. yezoensis, the wild type RZ (maternal strain) was crossed with the red mutant HT (paternal strain) and 30 color-sectors from 11 F1 gametophytic blades were examined. The complete chloroplast and mitochondrial genomes of the red mutant (HT) were assembled for the first time. One reliable and stable single nucleotide polymorphism (SNP) loci filtrated by bioinformatics analysis was used as a molecular marker for chloroplast and mitochondrial DNA, respectively, in subsequent experiments. PCR amplification and sequence analysis showed that the haplotypes of color-sectors detected were consistent with those of the maternal parent, confirming that both chloroplast and mitochondrial genomes were inherited maternally in P. yezoensis. The inheritance pattern of organelles in P. yezoensis can be used to guide the hybridization and breeding of nori. Additionally, the organelle SNP markers developed in this study can be applied in subsequent genetic research.