Ultrastructural and molecular characterization of Tetraselmis strains (Chlorodendrophyceae, Chlorophyta) isolated from Chile/Caracterización ultraestructural y molecular de cepas de Tetraselmis (Chlorodendrophyceae, Chlorophyta) aisladas de Chile

• Published in: Gayana. Botánica. 2015-01, Vol.72 (1), p.47
• Main Authors: González, Mariela A, Aguayo, Paula A, Inostroza, Ingrid De L, Castro, Pablo A, Fuentes, Glenda A, Gómez, Patricia I
• Format: Article
• Language: English
• Subjects: Cells; Organisms; Studies; Taxonomy
• ISSN: 0016-5301; 0717-6643

Species of the genus Tetraselmis (Chlorodendrophyceae, Chlorophyta) have traditionally been used in aquaculture facilities as food for larval varieties of marine organisms. Recently, some strains with high lipid content have been considered as having potential for biofuel production. Although many Tetraselmis species are relatively well-characterized using light and electron microscopical methods, there are still taxonomic ambiguities among the species. DNA sequence analysis, which provides a reliable and more convenient tool for species delimitation, has been poorly used in Tetraselmis. In this study, three strains of Tetraselmis, isolated from coastal Chilean waters, have been characterized using an integrative approach (light and electron microscopy, molecular phylogeny of ITS, including secondary structure analysis). According to the pyrenoid ultrastructure of the strains investigated two of them (from Dichato and Coliumo) belong to the subgenus Parviselmis, while the Caldera strain corresponds to the subgenus Tetrathele. Even though it was not possible to identify the strains at species level, it was clearly demonstrated by phylogenetic analyses of ITS-1 and ITS-2 sequences and by ITS-2 secondary structure that the Dichato and Coliumo strains are the same species, and could belong either to T. suecica or T. chui. However, the Caldera strain might correspond to an undescribed species. As our study has shown, the genus Tetraselmis needs to be taxonomically revised using an integrative approach, which includes the investigations of authentic strains of this genus.