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Ecological and genomic features of two widespread freshwater picocyanobacteria
Author(s) -
CabelloYeves Pedro J.,
Picazo Antonio,
Camacho Antonio,
Callieri Cristiana,
Rosselli Riccardo,
RodaGarcia Juan J.,
Coutinho Felipe H.,
RodriguezValera Francisco
Publication year - 2018
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14377
Subject(s) - biology , genome , metagenomics , synechococcus , cyanobacteria , leptospira , ecology , gene , evolutionary biology , genetics , bacteria , microbiology and biotechnology , serotype
Summary We present two genomes of widespread freshwater picocyanobacteria isolated by extinction dilution from a Spanish oligotrophic reservoir. Based on microscopy and genomic properties, both picocyanobacteria were tentatively designated Synechococcus lacustris Tous, formerly described as a metagenome assembled genome (MAG) from the same habitat, and Cyanobium usitatum Tous, described here for the first time. Both strains were purified in unicyanobacterial cultures, and their genomes were sequenced. They are broadly distributed in freshwater systems; the first seems to be a specialist on temperate reservoirs (Tous, Amadorio, Dexter, Lake Lanier, Sparkling), and the second appears to also be abundant in cold environments including ice‐covered lakes such as Lake Baikal, Lake Erie or the brackish Baltic Sea. Having complete genomes provided access to the flexible genome that does not assemble in MAGs. We found several genomic islands in both genomes, within which there were genes for nitrogen acquisition, transporters for a wide set of compounds and biosynthesis of phycobilisomes in both strains. Some of these regions of low coverage in metagenomes also included antimicrobial compounds, transposases and phage defence systems, including a novel type III CRISPR‐Cas phage defence system that was only detected in Synechococcus lacustris Tous.