Spiribacter halobius sp. nov., a novel halophilic Gammaproteobacterium with a relatively large genome

Spiribacter is the most abundant bacterial genus in intermediate-salinity zones of hypersaline environments. However, strains are extremely difficult to isolate pure culture. Therefore, characteristics, genome features, and adaption mechanisms that allow thrive highly saline conditions largely unknown. Here, we show predominant brines from marine solar salterns sulfate-type salt lakes with intermediate saturated salinities. Using a high-salt medium, isolated novel strain, halobius E85 T , which possesses relatively large distinct genome. The strain has length 4.17 Mbp, twice other species genomes largest described within family Ectothiorhodospiraceae . Comparative genomic analyses indicate approximately 50% genes strain-specific, endowing functional differences its metabolic capabilities, biosynthesis compatible solutes, transport pumping solutes into cell environment. Hundreds insertion sequences result many pseudogenes frequent gene fragment rearrangements Dozens islands, significant preference for replication, recombination repair, motility may have been gained species, scattered This study provides important insights general genetic basis abundance environments strain-specific evolutionary strategies