PHYLOGENY OF THE CHLOROPHYCEAE WITH SPECIAL REFERENCE TO THE SPHAEROPLEALES: A STUDY OF 18S AND 26S rDNA DATA

Abstract

Ultrastructural analyses of the flagellar apparatus suggested that Sphaeroplea , Atractomorpha , the Hydrodictyaceae, and the Neochloridaceae, all of which produce biflagellate motile cells with directly opposed (DO) basal bodies, are allied in an order Sphaeropleales. Recent studies of 18S rDNA sequence data supported an alliance of the DO group, but no data from Sphaeroplea and its allies were included. This investigation presented a test of the phylogenetic hypothesis suggested by the flagellar apparatus evidence using sequence data from the nuclear-encoded small-subunit rDNA (18S) and large subunit rDNA (26S) genes, combined with additional taxon sampling. Results from phylogenetic analyses weakly supported monophyly of biflagellate DO taxa and indicated that pyrenoids with cytoplasmic invaginations are present in numerous distinct lineages. Analysis of both molecular data sets supported a class Chlorophyceae comprised of at least six major groups that generally correspond to currently recognized orders or families: Chaetophorales, Chaetopeltidales, Chlamydomonadales, Sphaeropleales, Sphaeropleaceae, and Oedogoniales. In addition, Cylindrocapsa , Elakatothrix , Treubaria , and Trochiscia formed a seventh chlorophycean clade that is new to science. This investigation demonstrated that the 26S rDNA gene provides more phylogenetic signal, per unit sequence, than the 18S rDNA gene and that combined analysis yields topologies with more robust support than independent analysis of either data set.

The blood alga: phylogeny ofHaematococcus(Chlorophyceae) inferred from ribosomal RNA gene sequence data

“…Genomic DNA templates were used for PCR as described previously for both 18S and 26S rDNA (Buchheim et al, 2001) and ITS2 (Buchheim et al, 2005(Buchheim et al, , 2010. Although most sequencing templates were prepared as described previously (Buchheim et al, 1990;Buchheim & Chapman, 1991;Buchheim et al, 2001), some PCR products were generated using illustra™ PuReTaq™ Ready-to-Go™ PCR beads (GE Healthcare, Buckinghamshire, UK).…”

“…Although most sequencing templates were prepared as described previously (Buchheim et al, 1990;Buchheim & Chapman, 1991;Buchheim et al, 2001), some PCR products were generated using illustra™ PuReTaq™ Ready-to-Go™ PCR beads (GE Healthcare, Buckinghamshire, UK). PCR products were purified using reagents and supplies included with the illustra™ GFX™ PCR DNA and Gel Band Purification Kits (GE Healthcare).…”

“…Outgroup data were used to root all trees. The outgroup taxa -Ankistrodesmus, Acutodesmus, Neochloris, Hydrodictyon and Pediastrum -belong to the order Sphaeropleales which is regarded as a sister group to the chlamydomonadalean flagellates (Buchheim et al, 2001).…”

Morphology and rDNA phylogeny of a Mediterranean <em>Coolia monotis</em> (Dinophyceae) strain from Greece

“…In phylogeny, using the LSU is imperative for lower level taxonomic analysis in order to discriminate between closely related taxa at the genus, species and even strain level (Baroin-Tourancheau et al, 1992;Buchheim et al, 2001;Harper and Saunders, 2001;John et al, 2003). D1-D6 are phylogenetically useful variable domains ("D" regions; Hassouna et al, 1984;Michot et al, 1984) within the LSU sequence of dinoflagellates Edvardsen et al, 2003;Murray et al, 2004).…”

Algas planctônicas flageladas e cocoides verdes de um lago no Parque Beija-Flor, Goiânia, GO, Brasil

“…Sphaeropleales apresenta organismos unicelulares, filamentosos ou cenobiais com o aparato flagelar com corpos basais diretamente opostos (DO) (Buchheim et al 2001). Chlorellales compreende indivíduos com organização morfológica em unicelulares, colôniais e aparato flagelar CCW , Pröschold & Leliaert 2007.…”