title: Heterocyte-forming cyanobacteria from Brazilian saline-alkaline lakes.
abstract: Studies investigating the diversity of cyanobacteria from tropical environments are scarce, especially those devoted to the isolation and molecular characterization of the isolated strains. Among the Brazilian biomes, Pantanal has mainly been examined through microscopic observation of environmental samples, resulting in lists of morphotypes without any genetic information. Recently, two studies were conducted evaluating the morphologic and genetic diversity of cultured non-heterocytous cyanobacteria in this biome, which resulted in the separation and description of two novel genera. In order to complement the diversity of cultured cyanobacteria from saline-alkaline lakes in Pantanal, the present study is dedicated to the examination of cultured nitrogen-fixing heterocytous cyanobacteria from this extreme and underexplored environment. A total of fourteen cyanobacterial strains were isolated. According to morphological examination they belong to the order Nostocales and to the subsections IV.I and IV.II, according to the International Code of Nomenclature for Algae, Fungi and Plants and the Bergey's Manual of Systematic Bacteriology, respectively. Phylogenetic evaluation of their 16S rRNA gene sequences resulted in the formation of five clusters. Among them, one is clearly related to the genus Anabaenopsis whilst the remaining clusters may represent new genetic lineages. These novel sequences aid in the delimitation of problematic groups, especially those containing sequences belonging to mixed genera. The application of both morphologic and phylogenetic studies has proven to be an important tool in resolving problematic groups in cyanobacteria systematics. This strategy is essential in order to detect novel cyanobacteria genera from other tropical environments.
authors.affiliation: University of São Paulo, Center for Nuclear Energy in Agriculture, Laboratory of Cellular and Molecular Biology, 13400-970 Piracicaba, São Paulo, Brazil; EMBRAPA Environment, Laboratory of Environmental Microbiology, 13820-000 Jaguariúna, São Paulo, Brazil. Electronic address: genuario@gmail.com.
authors.forename: Diego Bonaldo
authors.initials: DB
authors.lastname: Genuário
authors.affiliation: University of São Paulo, Center for Nuclear Energy in Agriculture, Laboratory of Cellular and Molecular Biology, 13400-970 Piracicaba, São Paulo, Brazil. Electronic address: apdini@gmail.com.
authors.forename: Ana Paula Dini
authors.initials: APD
authors.lastname: Andreote
authors.affiliation: University of São Paulo, Center for Nuclear Energy in Agriculture, Laboratory of Cellular and Molecular Biology, 13400-970 Piracicaba, São Paulo, Brazil; Universidade Federal de Viçosa, Departamento de Biologia Vegetal, 36570-900 Viçosa, Minas Gerais, Brazil. Electronic address: marcelogmvvaz@gmail.com.
authors.forename: Marcelo Gomes Marçal Vieira
authors.initials: MGMV
authors.lastname: Vaz
authors.affiliation: University of São Paulo, Center for Nuclear Energy in Agriculture, Laboratory of Cellular and Molecular Biology, 13400-970 Piracicaba, São Paulo, Brazil. Electronic address: fiore@cena.usp.br.
authors.forename: Marli Fátima
authors.initials: MF
authors.lastname: Fiore
mesh_terms: D001938:Brazil; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D060106:Lakes / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Extreme environments; Nitrogen-fixers; Pantanal; Phylogeny; Tropical diversity