Evolution and photosynthesis of polar cyanobacteria

Cyanobacteria are the only bacteria capable of oxygenic photosynthesis. They are cosmopolitan, but especially successful in extreme habitats such as Polar regions. However, adaptation of photosynthesis to these habitats, where extreme fluctuations in irradiance and temperature are commonplace, remains poorly understood. Cyanobacterial dominance in these environments suggests a capacity to acclimate photosynthesis to challenging conditions. The mechanics of such adaptations can provide insights into the evolution of such extremophiles, applications for biotechnology, and a deeper understanding of the biological plasticity allowing the endurance of oxygenic photosynthesis over the long history of our constantly changing planet.

The aim of the project is to characterize in real-time, at a physiological and genomic level, how photosynthesis in cyanobacteria acclimates to harsh environmental conditions. Experiments will grow the same cultures of Polar cyanobacteria in 'polar-like' conditions, and temperate conditions, to characterise polar adaptation, and explore the degree to which these characteristics are conserved or flexible. Responses to stresses such as extreme light intensities and changes in temperature will be compared across each experimental set up, and to a temperate 'model' strain that is commonly used in laboratory work and industry. Photophysiological activity will be recorded and compared, as will genomes, transcriptomes, and the degree of DNA methylation. Changes will be correlated with photosynthetic performance.

The NHM hosts cyanobacteria collected on Captain Scott's Antarctic Expedition that will be sequenced using ancient DNA approaches and compared with modern isolates and available data from Antarctica. This will produce a century long genomic history of Antarctic cyanobacteria, providing insight into recent genomic changes of these species and how industrialisation, and dramatic climate change, can affect these important primary producers.