Morphological, molecular and ecophysiological characterization of the phototrophic dinoflagellate Biecheleriopsis adriatica from Korean coastal waters

Abstract

Biecheleriopsis is a genus of small marine planktonic dinoflagellates. Here, we present detailed morphological, molecular and ecophysiological characterizations of Biecheleriopsis adriatica based on a number of strains from Korea. The small subunit (SSU) ribosomal DNA (rDNA) sequences of two of the three Korean strains were closely related to those of previously described B. adriatica, and one was identical. However, the large subunit (LSU) and internal transcribed spacer region (ITS1, ITS2 and 5.8S) sequences from the Korean strains differed by 0.1-0.6% and 1.0-1.6%, respectively, from the non-Korean strains. In phylogenetic trees built on the basis of the SSU and LSU (D1-D3) rDNA and ITS region sequences, the Korean strains clustered within a clade including all the other B. adriatica strains. Morphologically, the Korean strains resemble those described from the Adriatic Sea. However, some cells of the Korean strains had nine latitudinal rows of amphiesmal vesicles (AVs): three episomal, three cingular, and three hyposomal rows, which is fewer than the 11 rows reported in the non-Korean strains. In addition, we report for the first time that B. adriatica has 11 sulcal plates and a small vesicle in the hyposomal ventral side. Peridinin was found to be the main accessory pigment in the Korean strains of B. adriatica. The Korean strains were not toxic to the brine shrimp Artemia salina.