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Prochlorothrix hollandica is filamentous non-heterocystous cyanobacterium which possesses the chlorophyll a/b light-harvesting complexes. Despite the growing interest in unusual green-pigmented cyanobacteria (prochlorophytes) to date only a few sequenced genome from prochlorophytes genera have been reported. This study sequenced the genome of Prochlorothrix hollandica CCAP 1490/1T (CALU1027). The produced draft genome assembly (5.5 Mb) contains 3737 protein-coding genes and 114 RNA genes. [ABSTRACT FROM AUTHOR]

'Bacterial consortium' sensu lato applies to mutualism or syntrophy-based systems consisting of unrelated bacteria. Consortia of cyanobacteria have been preferentially studied on A nabaena epibioses; non-photosynthetic satellites of other filamentous or unicellular cyanobacteria were also considered although structure-functional data are few. At the same time, information about consortia of cyanobacteria which have light-harvesting antennae distinct from standard phycobilisome was missing. In this study, we characterized first, via a polyphasic approach, the cultivable consortium of P rochlorothrix hollandica CCAP 1490/1 (filamentous cyanobacterium which contains chlorophylls a, b/carotenoid/protein complex in the absence of phycobilisome) and non-photosynthetic heterotrophic bacteria. The strains of most abundant satellites were isolated and identified. Consortium metagenome reconstructed via 454-pyro and Illumina sequencing was shown to include, except for P . hollandica, several phylotypes of P roteobacteria and Bacteroidetes. The ratio of consortium members was essentially stable irrespective of culture age, and restored after artificially imposed imbalance. The consortium had a complex spatial arrangement as demonstrated by FISH and SEM images of the association, epibiosis, and biofilm type. Preliminary data of metagenome annotation agreed with the hypothesis that satellite bacteria contribute to P . hollandica protection from reactive oxygen species ( ROS). [ABSTRACT FROM AUTHOR]

Cyanobacteria that possess phycobilisomes, light-harvesting antenna, have been well studied. In contrast, more rare green cyanobacteria (four genera/five species) that instead make use of chlorophyll-protein complex are poorly studied. In particular, the genus Prochlorothrix is represented by a small environmental DNA database and reports of only two cultured species from Northern Europe. In this work, marine and freshwater habitats of Northwestern Russia were investigated. PCR with Prochlorothrix 16S rRNA gene specific primers, FISH analysis with a Prochlorothrix 16S rRNA-targeted probe, Prochlorothrix culture isolation, and phylogenetic analysis of Prochlorothrix diversity were carried out. We identified Prochlorothrix 16S rDNA in samples from the St. Petersburg region and corroborated this finding by FISH. Attempts to isolate PCR- and FISH-detected Prochlorothrix strains were unsuccessful. Phylogenetic analysis revealed that the Prochlorothrix 16S rDNA sequences identified were very similar and formed a single cluster with high bootstrap support. Some of these sequences represent environmental strains of the species Prochlorothrix hollandica and P. scandica, while the others belong to new Prochlorothrix species or even to a new Prochlorothrix-related genus. Our results suggest a broader distribution and greater diversity in Prochlorothrix than previously thought. [ABSTRACT FROM AUTHOR]