Genome-based characterization of the deep-sea psychrotolerant bacterium Bacillus altitudinis SORB11 isolated from the Indian Sector of the Southern Ocean

Life under deep-sea undergoes unusual adaption, especially with darkness, increased pressure, cold, and recalcitrant carbon. Microbes in the deep sea usually evolved through selection and are likely to increase little important natural ability like motility, surface adhesion, and membrane with polyunsaturated fatty acids. Sporulation within the genus Bacillus may perhaps play an important role for survival in the deep-sea biosphere. Bacillus altitudinis SORB11 was isolated from the dark and cold deep-sea environment of the Southern Ocean. Violet radiation and starvation were primarily investigated and characterized; the bacterial strain is a motile, free-living, bathypelagic, psychrotolerant. Genome of the strain B. altitudinis SORB11 consisting of 3.6 Mb circular chromosome with an average 41.2% GC predictably included Brevibacillus phage genome. The genome harbored a considerable number of foreign genetic materials that would likely to be acquired by the lateral gene transfer. Moreover, the energy metabolic pathway associated genes, potentially involved in methane, sulfur, and nitrogen metabolisms, are essentially present in the genome. Cells of the strain were capable to withstand more than 1800 Jcmˉ 2 exposure of UV-B radiation, consequently, the exposed cells were characterized by having thick cell-wall and reduced cell shape and size. UvrA and UvrB proteins from UvrABC repair system were over-expressed in the treated cells. So, detailed investigations on such adaptations might help to understand the origin and evolution of extremophilic organisms. Graphical abstract