University of Bristol researchers have scoured the genome of a cyanobacterium that lives in Arctic, Antarctic, and alpine locales for hints as to how it survives in such extreme habitats.
As Bristol's Patricia Sánchez-Baracaldo and her colleagues report in BMC Genomics, they sequenced the genome of Phormidesmis priestleyi BC1401, which was isolated from the Greenland Ice Sheet. Their phylogenetic analyses indicated that P. priestleyi is a sister lineage to Phormidesmis ANT.L61.2 from Antarctica and that, together, these lineages fall within a group of small cell diameter filamentous lineages among the Microcyanobacteria.
They also compared known cold-adaption genes housed in the P. priestleyi genome to those of three other bacteria. However, the researchers found that the P. priestleyi genome is similar to those of its relatives from warmer spots on the globe. Instead, Sánchez-Baracaldo and her colleagues say that P. priestleyi likely relies on a biofilm of extracellular polymeric substances (EPS) to withstand the cold. They noted that the Wsp chemosensory pathway could provide a link between the environment and EPS production.
"Our work shows that by wrapping itself in a protective layer made out of a complex arrangement of sugars, this microbe uses this sticky layer to protect its cells from freezing, allowing it to survive through the Arctic winter," Sánchez-Baracaldo says in a statement. "Interestingly, other cyanobacteria species use similar strategies in order to survive in other extreme habitats. Such strategies have allowed cyanobacteria to colonize some of the most inhospitable places on our planet."