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 N2-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.

Roholtiella, gen. nov. (Nostocales, Cyanobacteria)—a tapering and branching cyanobacteria of the family Nostocaceae

“…While the thylakoid structure is fairly unique in appearance, in general it is congruent with the irregular thylakoid structure of other heterocytous cyanobacteria (compare e.g. Brito et al 2012). …”

Bioprospecting Portuguese Atlantic coast cyanobacteria for bioactive secondary metabolites reveals untapped chemodiversity

“…In a previous study, several cyanobacterial strains were isolated from nine sites in the intertidal zones along the Portuguese Atlantic coast and extensively characterized using a polyphasic approach [16]. These strains were shown to be morphologically and phylogenetically very diverse belonging to orders Chroococcales, Pleurocapsales, Oscillatoriales and Nostocales (Subsections I through IV).…”

Hassallia littoralis sp. nov. (Cyanobacteria, Microchaetaceae) from Mexico’s marine supralittoral based on morphological and molecular evidence

“…This species was found growing with several undescribed coccoid and LPP species (Fig. 1) but not with common filamentous non-heterocystous (Oscillatoria, Lyngbya, Microcoleus, Phormidium, Schizothrix) or heterocystous genera (Rivularia, Calothrix, Scytonema) typically described for intertidal biotopes (Brito et al 2012).…”