title: Halotia gen. nov., a phylogenetically and physiologically coherent cyanobacterial genus isolated from marine coastal environments.
abstract: Nostoc is a common and well-studied genus of cyanobacteria and, according to molecular phylogeny, is a polyphyletic group. Therefore, revisions of this genus are urged in an attempt to clarify its taxonomy. Novel strains isolated from underexplored environments and assigned morphologically to the genus Nostoc are not genetically related to the 'true Nostoc' group. In this study, four strains isolated from biofilms collected in Antarctica and five strains originated from Brazilian mangroves were evaluated. Despite their morphological similarities to other morphotypes of Nostoc, these nine strains differed from other morphotypes in ecological, physiological and genetic aspects. Based on the phylogeny of the 16S rRNA gene, the Antarctic sequences were grouped together with the sequences of the Brazilian mangrove isolates and Nostoc sp. Mollenhauer 1 : 1-067 in a well-supported cluster (74 % bootstrap value, maximum-likelihood). This novel cluster was separated phylogenetically from the 'true Nostoc' clade and from the clades of the morphologically similar genera Mojavia and Desmonostoc. The 16S rRNA gene sequences generated in this study exhibited 96 % similarity to sequences from the nostocacean genera mentioned above. Physiologically, these nine strains showed the capacity to grow in a salinity range of 1-10 % NaCl, indicating their tolerance of saline conditions. These results provide support for the description of a new genus, named Halotia gen. nov., which is related morphologically to the genera Nostoc, Mojavia and Desmonostoc. Within this new genus, three novel species were recognized and described based on morphology and internal transcribed spacer secondary structures: Halotia branconii sp. nov., Halotia longispora sp. nov. and Halotia wernerae sp. nov., under the provisions of the International Code of Nomenclature for Algae, Fungi and Plants.
authors.affiliation: Center for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário 303, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Diego Bonaldo
authors.initials: DB
authors.lastname: Genuário
authors.affiliation: Center for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário 303, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Marcelo Gomes Marçal Vieira
authors.initials: MGMV
authors.lastname: Vaz
authors.affiliation: Universidade Luterana do Brasil, Rua Martinho Lutero 301, 96501-595 Cachoeira do Sul, RS, Brazil.|Institute of Botany, Nucleus of Phycology, Avenida Miguel Estéfano 3687, 04301-012 São Paulo, SP, Brazil.
authors.forename: Guilherme Scotta
authors.initials: GS
authors.lastname: Hentschke
authors.affiliation: Institute of Botany, Nucleus of Phycology, Avenida Miguel Estéfano 3687, 04301-012 São Paulo, SP, Brazil.
authors.forename: Célia Leite
authors.initials: CL
authors.lastname: Sant'Anna
authors.affiliation: Center for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário 303, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Marli Fátima
authors.initials: MF
authors.lastname: Fiore
mesh_terms: D000864:Antarctic Regions; D015373:Bacterial Typing Techniques; D018441:Biofilms; D001938:Brazil; D000458:Cyanobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D043982:Rhizophoraceae / Q000382:microbiology; D054712:Salinity; D017422:Sequence Analysis, DNA; D053833:Wetlands
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S