All Nostoc strains had a subtype I‐D system, but the polar specimens also showed evidence of a subtype I‐B system that has not been previously reported in cyanobacteria, suggesting diverse cyanobacteria‐virus interactions in the Arctic. There were a large number of unique repeat‐spacer arrays in each genome, indicating diverse histories of viral attack. Since viral‐host interactions contribute to microbial diversity, we analysed the CRISPR‐Cas systems in the Arctic and two temperate Nostoc species. Osmoprotection and other stress genes were found in all Nostoc strains, but the two Arctic strains had markedly higher numbers of biosynthetic gene clusters for uncharacterised nonribosomal peptide synthetases, suggesting a high diversity of secondary metabolites. Comparisons of the polar genomes with 26 present‐day non‐polar members of the Nostocales family highlighted that there are pronounced genetic variations among Nostoc strains and species. commune morphotype with a recent sample from the High Arctic and a herbarium specimen collected during the British Arctic Expedition (1875‐76). Here we carried out the first genomic analysis of the N. However, the genomic diversity of Nostoc is little known and there are no genomes available for polar Nostoc. Nostoc (Nostocales, Cyanobacteria) has a global distribution in the Polar Regions. This has direct implications in viral ecology, where the lysogenic- lytic switch is determined by nutrient abundance and microbial density but also by the metabolism type that prevails in the host community. Taken together, these observations suggest a nexus between the ecological role of the host (metabolism) and the type of viral lifestyle in thermophilic PMMs. These temperate viruses possess accessory genes to sense or control stress-related processes in their hosts, such as sporulation and biofilm formation. Likewise, lysogenic viruses were related exclusively to chemoheterotrophic bacteria from the phyla Proteobacteria, Firmicutes, and Actinobacteria. One of the most abundant lytic viral groups corresponded to cyanophages, which would infect the cyanobacteria Fischerella, the most active and dominant primary producer in thermophilic PMMs. Our results suggest that virus-specific replicative cycles (lytic and lysogenic) were associated with specific host taxa with different metabolic capacities. Furthermore, the presence of integrated prophage sequences in environmental metagenome-assembled genomes from published Porcelana PMM metagenomes was analyzed. The compositional changes of viral communities at two different sites were analyzed at the genomic and gene levels. We carried out viral metagenomics following in situ mitomycin C induction experiments in PMMs from Porcelana hot spring (Northern Patagonia, Chile). In hot springs, lysogeny is considered an active lifestyle, yet it has not been systematically studied in all habitats, with phototrophic microbial mats (PMMs) being particularly not studied. However, the mechanisms by which lysogenic viruses influence their host-microbial community are less clear. Viruses exert diverse ecosystem impacts by controlling their host community through lytic predator-prey dynamics. We conclude that the CRISPR/Cas system size varied among the lineages as well as the gene flow The Rupite strain had the highest, and JA-2-3Aa the lowest number of spacers among the analyzed strains, and the CRISPR spacers were only rarely shared among the strains. The CRISPR/Cas system had variable complexity among the species of Thermostichus in terms of both the number of spacers and genes. Furthermore, the horizontal gene transfer seemed to be more frequent among the geographically distant species than between the two species within the same hot spring.
We found that the Rupite strain is a distinct species from strains JA-2-3Aa, and JA-2-3B′a(2-13). We performed phylogenetic inference, horizontal gene transfer estimation, and CRISPR/Cas system characterization. We sequenced the whole genome of a strain Thermostichus vulcanus isolated from the Rupite spring (Bulgaria), which is closely related to Theromstichus strains JA-2-3Aa and JA-2-3B′a(2-13). Here, we characterized a new lineage within an anciently diverged thermophilic cyanobacteria.
#Prefix syn drivers#
Drivers of the speciation in bacteria, including geographical isolation and horizontal gene transfer, are still poorly understood.