title: Culture-dependent characterization of cyanobacterial diversity in the intertidal zones of the Portuguese coast: a polyphasic study.
abstract: Cyanobacteria are important primary producers, and many are able to fix atmospheric nitrogen playing a key role in the marine environment. However, not much is known about the diversity of cyanobacteria in Portuguese marine waters. This paper describes the diversity of 60 strains isolated from benthic habitats in 9 sites (intertidal zones) on the Portuguese South and West coasts. The strains were characterized by a morphological study (light and electron microscopy) and by a molecular characterization (partial 16S rRNA, nifH, nifK, mcyA, mcyE/ndaF, sxtI genes). The morphological analyses revealed 35 morphotypes (15 genera and 16 species) belonging to 4 cyanobacterial Orders/Subsections. The dominant groups among the isolates were the Oscillatoriales. There is a broad congruence between morphological and molecular assignments. The 16S rRNA gene sequences of 9 strains have less than 97% similarity compared to the sequences in the databases, revealing novel cyanobacterial diversity. Phylogenetic analysis, based on partial 16S rRNA gene sequences showed at least 12 clusters. One-third of the isolates are potential N(2)-fixers, as they exhibit heterocysts or the presence of nif genes was demonstrated by PCR. Additionally, no conventional freshwater toxins genes were detected by PCR screening.
authors.affiliation: IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Angela
authors.initials: A
authors.lastname: Brito
authors.forename: Vitor
authors.initials: V
authors.lastname: Ramos
authors.forename: Rui
authors.initials: R
authors.lastname: Seabra
authors.forename: Arlete
authors.initials: A
authors.lastname: Santos
authors.forename: Catarina L
authors.initials: CL
authors.lastname: Santos
authors.forename: Miguel
authors.initials: M
authors.lastname: Lopo
authors.forename: Sérgio
authors.initials: S
authors.lastname: Ferreira
authors.forename: António
authors.initials: A
authors.lastname: Martins
authors.forename: Rita
authors.initials: R
authors.lastname: Mota
authors.forename: Bárbara
authors.initials: B
authors.lastname: Frazão
authors.forename: Rosário
authors.initials: R
authors.lastname: Martins
authors.forename: Vitor
authors.initials: V
authors.lastname: Vasconcelos
authors.forename: Paula
authors.initials: P
authors.lastname: Tamagnini
mesh_terms: D059001:Aquatic Organisms / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001267:Atlantic Ocean; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D000458:Cyanobacteria / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D011174:Portugal; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C029130:nitrogenase reductase