• gametophyte;
  • Marchantia polymorpha;
  • molecular marker;
  • Saccharina (Laminaria) japonica;
  • sequence-characterized amplified region;
  • sex identification

PCR amplification was employed to identify female or male gametophyte associated markers in Saccharina japonica (Aresch.) C. E. Lane, C. Mayes et G. W. Saunders (=Laminaria japonica Aresch.). One pair of the primers, P5, was screened from five pairs designed based on a specific sequence (GenBank accession no. AB069714) of Marchantia polymorpha Y chromosome, resulting in a differential band ∼500 bp in size between female and male gametophytes of Rongfu strain of Sjaponica. According to the SCAR (sequence-characterized amplified regions) strategies, one pair of primers, P51, was designed on the basis of the sequence of this band that was only present in female gametophytes. A SCAR marker, designated FRML-494 (494-bp Female-Related Marker of S. japonica, GenBank accession no. EU931619), was developed successfully by PCR amplification using the designed P51 primer pair. The SCAR marker was verified to be present only in female gametophytes of another variety 901 of this kelp that was a hybrid between Sjaponica as paternal and Slongissima (Miyabe) C. E. Lane, C. Mayes, Druehl et G. W. Saunders (=Laminaria longissima Miyabe) as maternal, suggesting that the FRML-494 marker was specifically related to female gametophytes of the genus. This marker is the first molecular tool reported for sex identification in kelps. This study was beneficial for identifying gametophyte gender during vegetative growth and for judging whether the monogenetic sporophytes came from exclusive male or female gametophytes, as well as for further research on sex determination at the molecular level in kelps.