title: A multilocus sequence analysis approach to the phylogeny and taxonomy of the Halobacteriales.
abstract: Members of the order Halobacteriales are obligate extreme halophiles that belong to the domain Archaea. The classification of the Halobacteriales currently relies on a polyphasic approach, which integrates phenotypic, genotypic and chemotaxonomic characterization. However, the most utilized genetic marker for phylogeny, the 16S rRNA gene, has multiple drawbacks for use with the Halobacteriales: the species of many genera exhibit large intragenic differences between multiple ribosomal RNA operons, the gene is too conserved to discriminate reliably at the species level and it appears to be the most frequently recombined gene between closely related species. Moreover, the Halobacteriales is a rapidly expanding group due to recent successes at cultivating novel strains from a diverse set of hypersaline environments; a fast, reliable, inexpensive, portable molecular method for discriminating species is required for their investigation. Recently, multilocus sequence analysis (MLSA) has been shown to be an effective tool for strain identification and taxonomic designation, even for those taxa that experience frequent lateral gene transfer and homologous recombination. In this study, MLSA was utilized for evolutionary and taxonomic investigation of the Halobacteriales. Efficacy of the MLSA approach was tested across a hierarchical gradient using 52 halobacterial strains, representing 33 species (including names without standing in nomenclature) and 14 genera. A subset of 21 strains from the genus Haloarcula was analysed separately to test the sensitivity and relevance of the MLSA approach among closely related strains and species. The results demonstrated that MLSA differentiated individual strains, reliably grouped strains into species and species into genera and identified potential novel species and also family-like relationships. This study demonstrates that MLSA is a rapid and informative molecular method that will probably accommodate strain analysis at any taxonomic level within the Halobacteriales.
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: R Thane
authors.initials: RT
authors.lastname: Papke
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Emma
authors.initials: E
authors.lastname: White
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Prajwal
authors.initials: P
authors.lastname: Reddy
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Griffin
authors.initials: G
authors.lastname: Weigel
authors.affiliation: Halophiles Research Institute, Noda, Chiba 278-0043, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamekura
authors.affiliation: Bio-Nano Electronics Research Center, Toyo University, Kujirai, Kawagoe, Saitama 350-8585, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Minegishi
authors.affiliation: Bio-Nano Electronics Research Center, Toyo University, Kujirai, Kawagoe, Saitama 350-8585, Japan.
authors.forename: Ron
authors.initials: R
authors.lastname: Usami
authors.affiliation: Departamento de Microbiologia y Parasitologia, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ventosa
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D016931:Halobacteriales / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing / Q000379:methods*; D010802:Phylogeny
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal