LAUSR

A novel psychrotolerant Psychrobacillus strain PB01, isolated from an Antarctic iceberg, was comparatively analyzed with five related strains. The complete genome of strain PB01 consists of a single circular chromosome (4.3 Mbp) and a plasmid (19 Kbp). As potential low temperature adaption strategies strain PB01 has four genes encoding cold-shock proteins, two genes encoding DEAD-box RNA helicases, and eight genes encoding transporters for glycine betaine, which can serve as a cryoprotectant, on the genome. The pan-genome structure of the six Psychrobacillus strains suggest that strain PB01 might evolve to adapt to extreme environments by changing genome content such as high capacity for DNA repair, translation, and membrane transporter. Notably, strain PB01 possess a complete TCA cycle consisting of eight enzymes as well as additional Helicobacter pylori type three enzymes: ferredoxin-dependent 2-oxoglutarate synthase, succinyl-CoA/acetoacetyl-CoA transferase, and malate/quinone oxidoreductase. The co-existence of the genes for TCA cycle enzymes are also identified in the other five Psychrobacillus strains.