The survival toolkit of the Antarctic cyanobacterium Phormidesmis priestleyi ULC007

peer reviewedExtreme seasonality led by rapid changes in day length and harsh environmental conditions make Antarctica a unique habitat. Freshwater ecosystems range from cryoecosystems and ice shelf meltwater ponds to perennially ice-covered lakes where conspicuous benthic microbial mat communities constitute most of the biomass. In these mats, cyanobacteria form the matrix in which other microorganisms can live, and where they are the key primary producers and main drivers of the carbon and food webs[1]. Narrow filamentous cyanobacteria belonging to the order Pseudanabaenales are especially abundant in polar microbial mats [2]. Despite the dominance of cyanobacteria on the Antarctic continent, there is currently no study available on the genomic evolution of Antarctic cyanobacteria. Here we investigate the genome of a widely distributed Antarctic cyanobacterium, Phormidium priestleyi ULC007. To provide a better understanding of the survival strategies of this taxon, we used high-throughput sequencing technologies to investigate its geographic distribution and genome evolution. More precisely, we investigated the abundance of genes in targeted functional categories based on the RAST subsystems technology, so as to provide a better overview of the genetic mechanisms involved in cold adaptation and circadian oscillation [3]. In Polar regions, low temperatures lead to the success of particular organisms featuring adaptations to molecular and cellular disturbances such as rigidity of membranes, reduction of enzyme-catalyzed reactions, and solute transport. Our main results underline the importance of functional categories of genes involved in the production of key molecules for the survival of polar P. priestleyi (e.g. exopolysaccharides, chaperone proteins, fatty acids and phospholipids)