title: A polyphasic approach leading to the revision of the genus Planktothrix (Cyanobacteria) and its type species, P. agardhii, and proposal for integrating the emended valid botanical taxa, as well as three new species, Planktothrix paucivesiculata sp. nov.ICNP, Planktothrix tepida sp. nov.ICNP, and Planktothrix serta sp. nov.ICNP, as genus and species names with nomenclatural standing under the ICNP.
abstract: Twenty strains of Planktothrix and five of 'Oscillatoria' were characterized by a polyphasic approach, for clarification of their taxonomic relationships. Emphasis was given to the strains (17) of the Pasteur Culture Collection of Cyanobacteria (PCC). Phenotypic characters analyzed comprised morphology, phycobiliprotein composition, temperature and salinity tolerance. The gvpA gas vesicle gene was detected by PCR in all strains, and transmission electron microscopy confirmed gas vesicle formation in the strains of 'Oscillatoria'. MALDI-TOF mass spectrometry revealed 13 chemotypes, nine of which produce microcystins. A multi-locus sequence typing (MLST) analysis was conducted using individual and concatenated nucleotide sequences of the 16S rDNA, internal transcribed spacer (ITS), gyrB, rpoC1 and rpoB. The results highlighted an unexpected diversity within the genus Planktothrix, showing that the five strains of 'Oscillatoria' need to be included in this taxon. Consequently, the genus consists of seven phylogenetic clusters, three of which represent new species, named Planktothrix paucivesiculata sp. nov.ICNP (type strain: PCC 8926T), Planktothrix tepida sp. nov.ICNP (type strain: PCC 9214T) and Planktothrix serta sp. nov.ICNP (type strain: PCC 8927T). These, together with the emended genus Planktothrix and its type species P. agardhii, valid taxa under the ICN, are described/re-described for gaining nomenclatural standing under the ICNP.
authors.affiliation: Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France; Centre d'Analyse Environnementales, Bât. Dufy, 1 place de Turenne, 94417 Saint-Maurice Cedex, France. Electronic address: virginie.gaget@adelaide.edu.au.
authors.forename: Virginie
authors.initials: V
authors.lastname: Gaget
authors.affiliation: AnagnosTec GmbH, Am Mühlenberg 11, 14476 Potsdam-Golm, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Welker
authors.affiliation: Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France.
authors.forename: Rosmarie
authors.initials: R
authors.lastname: Rippka
authors.affiliation: Institut Pasteur, Unité des Cyanobactéries, Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA) 2172, 75724 Paris Cedex 15, France.
authors.forename: Nicole Tandeau
authors.initials: NT
authors.lastname: de Marsac
mesh_terms: D016000:Cluster Analysis; D000458:Cyanobacteria / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D022162:Cytoplasmic Vesicles / Q000648:ultrastructure; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D052979:Phycobiliproteins / Q000032:analysis; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D009626:Terminology as Topic
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D052979:Phycobiliproteins; D012336:RNA, Ribosomal, 16S; D012321:DNA-Directed RNA Polymerases; D027081:DNA Gyrase
keywords: 16S rRNA gene; ITS; MLST; Planktothrix Anagnostidis & Komárek 1988(ICN) emend. gen. nov.(ICNP); Planktothrix agardhii Anagnostidis & Komárek 1988(ICN) emend. sp. nov.(ICNP); Polyphasic taxonomy; gyrB; rpoB; rpoC1