title: psbD sequences of Bumilleriopsis filiformis (Heterokontophyta, Xanthophyceae) and Porphyridium purpureum (Rhodophyta, Bangiophycidae): evidence for polyphyletic origins of plastids.
abstract: The nucleotide sequences of the plastidal psbD genes of Bumilleriopsis filiformis and Porphyridium purpureum (encoding the D2 protein of photosystem II) are reported in this paper. The Bumilleriopsis sequence clusters together with Porphyridium when a most parsimonious protein tree of D2 sequences is constructed. A composite D1/D2 protein-similarity network reveals that neither the three red algal sequences nor the two heterokontophyte sequences (Bumilleriopsis, xanthophytes and Ectocarpus, phaeophytes) group together. Therefore, the Heterokontophyta and Rhodophyta may be heterogeneous groups. Instead, it emerges that the D1/D2 proteins of Porphyridium and Bumilleriopsis clearly form a tight cluster. D1 and D2 proteins apparently do not provide a reliable molecular clock. These results fit into hypotheses proposing a polyphyletic origin for complex plastids, even among the supposedly "natural" group of heterokontophytes.
authors.affiliation: Institut für Mikrobiologie, FML, Technische Universität München, Freising, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Scherer
authors.forename: S
authors.initials: S
authors.lastname: Lechner
authors.forename: P
authors.initials: P
authors.lastname: Böger
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D004247:DNA; D056890:Eukaryota / Q000235:genetics* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045332:Photosystem II Protein Complex; D010802:Phylogeny; D018087:Plastids; D000461:Rhodophyta / Q000235:genetics* / Q000648:ultrastructure; D012689:Sequence Homology, Nucleic Acid
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D004247:DNA