Evolution and Distribution of Cyanobacteria

Abstract

Cyanobacteria are the ancient group of photosynthetic prokaryotes having pronounced variations in their physiological capacities, cellular differentiation strategies, and choice of habitats. They are the inventors of oxygenic photosynthesis on this planet and hence have played a crucial role in the evolution of biodiversity on Earth by gradually changing the atmospheric chemistry to be suitable for the evolution of eukaryotes. This conversion of atmosphere from anaerobic to an aerobic one was started by cyanobacteria through oxygenic photosynthesis, which finally supplied oxygen to the atmosphere for ~1.5 billion years leading to greater diversification of life on the Earth. Cyanobacteria inhabit a wide range of terrestrial and aquatic environments varying from the hot springs to polar region and other extreme environments. Their long-standing evolutionary history might be the reason for their success in acclimatization and sustenance in such diverse habitats. A high tolerance level of free sulfide and low oxygen, tolerance to lethal ultraviolet radiations, and the capacity to use H2S in place of H2O as a photoreductant are some of the various features of cyanobacteria that have aided in supporting their long history on this planet. Still, the picture regarding evolution and diversification of this ecologically and biotechnologically important group of photoautotrophs is not very clear. In this chapter, we present an overview of structural and genomic evolution of cyanobacteria and their distribution in diverse habitats on Earth. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021.