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Characterization of freshwater benthic biofilm‐forming H ydrocoryne ( C yanobacteria) isolates from A ntarctica
Author(s) -
Genuário Diego Bonaldo,
Corrêa Débora Machado,
Komárek Jiří,
Fiore Marli Fátima
Publication year - 2013
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/jpy.12124
Subject(s) - biology , phylogenetic tree , 16s ribosomal rna , phylogenetics , gene , microbiology and biotechnology , genetics
The aims of this work were to study cyanobacterial isolates resembling the genus H ydrocoryne using a combination of morphology and phylogeny of 16S r RNA and nifH sequences and to investigate genes involved in cyanotoxin and protease inhibitor production. Four new cyanobacterial strains, isolated from biofilm samples collected from K ing G eorge I sland, A ntarctica, were studied. In terms of morphology, these new strains share traits similar to true A nabaena morphotypes (benthic ones), whereas phylogenetic analysis of their 16S r RNA gene sequences grouped them with the sequence of the type species H ydrocoryne spongiosa (H. Schwabe ex Bornet and Flahault 1886–1888), but not with sequences of the type species from the genus A nabaena . This cluster is the sister group of A nabaena morphotypes isolated only from the G ulf of F inland. In addition, this cluster is related to two other clusters formed by sequences of A nabaena isolated from different sites. Partial nifH genes were sequenced from two strains and the phylogenetic tree revealed that the A ntarctic nifH sequences clustered with sequences from A nabaena . Furthermore, two strains were tested, using PCR with specific primers, for the presence of genes involved in cyanotoxins (microcystin and saxitoxin) and protease inhibitor (aeruginosin, and cyanopeptolin). Only cyanopeptolin was amplified using PCR . These four H ydrocoryne strains are the first to be isolated and sequenced from A ntarctica, which improves our knowledge on this poorly defined cyanobacterial genus.