AUTHOR=Pinevich Alexander V., Velichko Nataliya V., Ivanikova Natalia V.

TITLE=Cyanobacteria of the Genus Prochlorothrix†

JOURNAL=Frontiers in Microbiology

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2012.00173

DOI=10.3389/fmicb.2012.00173

ISSN=1664-302X

ABSTRACT=<p>Green cyanobacteria differ from the blue–green cyanobacteria by the possession of a chlorophyll-containing light-harvesting antenna. Three genera of the green cyanobacteria namely <italic>Acaryochloris</italic>, <italic>Prochlorococcus</italic>, and <italic>Prochloron</italic> are unicellular and inhabit marine environments. <italic>Prochlorococcus marinus</italic> attracts most attention due to its prominent role in marine primary productivity. The fourth genus <italic>Prochlorothrix</italic> is represented by the filamentous freshwater strains. Unlike the other green cyanobacteria, <italic>Prochlorothrix</italic> strains are remarkably rare: to date, living isolates have been limited to two European locations. Taking into account fluctuating blooms, morphological resemblance to <italic>Planktothrix</italic> and <italic>Pseudanabaena</italic>, and unsuccessful attempts to obtain enrichments of <italic>Prochlorothrix</italic>, the most successful strategy to search for this cyanobacterium involves PCR with environmental DNA and <italic>Prochlorothrix</italic>-specific primers. This approach has revealed a broader distribution of <italic>Prochlorothrix</italic>. Marker genes have been found in at least two additional locations. Despite of the growing evidence for naturally occurring <italic>Prochlorothrix</italic>, there are only a few cultured strains with one of them (PCC 9006) being claimed to be axenic. In multixenic cultures, <italic>Prochlorothrix</italic> is accompanied by heterotrophic bacteria indicating a consortium-type association. The genus <italic>Prochlorothrix</italic> includes two species: <italic>P. hollandica</italic> and <italic>P. scandica</italic> based on distinctions in genomic DNA, cell size, temperature optimum, and fatty acid composition of membrane lipids. In this short review the properties of cyanobacteria of the genus <italic>Prochlorothrix</italic> are described. In addition, the evolutionary scenario for green cyanobacteria is suggested taking into account their possible role in the origin of simple chloroplast.</p>