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Members of the genus Exiguobacterium are found in diverse environments from marine and fresh waters to permafrost and hot springs. As such, they can grow at a wide range of temperature, pH, salinity, and heavy-metal concentrations. Here we propose Exiguobacterium pavilionensis sp. nov. strain RW2 using phylogenetic, biochemical, and genome analyses. Isolated from a cold freshwater microbialite in Pavilion Lake, British Columbia, E. pavilionensis can grow between 4 and 50 °C, the broadest temperature range reported for the genus. The three Mbp circular genome includes a large set of core genes associated with stress responses to temperature, salinity and heavymore » metals that are conserved among all sequenced strains of Exiguobacterium spp., and which may explain their distribution across such a wide range of ecosystems. We also nominate potential pathways involved in carbonate precipitation (and therefore microbialite formation), as well as carotenoid biosynthesis that could lend the characteristic orange color to members of the genus. The unexpectedly high thermal tolerance of this cold-water bacterium, as well as its latent flagellum synthesis operons, suggest that this species may have had its evolutionary origins in a much warmer environment in which motility was important. These results provide further insight into the potential of Exiguobacterium to exploit a wide range of environmental conditions.« less

Members of the bacterial genus Agrococcus are globally distributed and found across highly diverse environments including forests, deserts, potatoes, coal mines, and cheese. Despite their widespread occurrence, the extent of their genetic diversity is poorly explored and no complete reference genomes are available. Using whole-genome analysis, chemotaxonomic markers, morphology, and 16S rDNA phylogeny we characterize the new species Agrococcus pavilionensis strain RW1, and provide the first complete genome from a member of the genus Agrococcus. The A. pavilionensis genome consists of one chromosome (2,627,177 bp) as well as two plasmids (HC-CG1 1,427 bp, and LC-RRW783 31,795 bp) that reveal considerablemore » genetic promiscuity, and include a prophage-like element on the main chromosome, and plasmid genes involved in integration, transposition, and heavy-metal stress. Agrococcus pavilionensis strain RW1 differs from other members of the genus in having a novel phospholipid fatty acid iso-C15:1Δ⁴, ß-galactosidase activity, filamentous growth under carbon stress, and amygdalin utilization. Both Agrococcus pavilionensis and Agrococcus lahaulensis encode a gene cluster that is likely involved in the synthesis of carotenoids and the production of the characteristic yellow pigmentation found in Agrococcus spp. The widespread occurrence of this genus across a remarkable range of diverse environments, and its genetic plasticity, hints at the ecological significance of Agrococcus spp.« less