Genomics of cyanobacteria: New insights and lessons for shaping our future

Abstract Cyanobacteria, the only known photosynthetic prokaryotes, are ancient organisms regarded as the producers of the Earth's oxygenic atmosphere and the ancestors of plant chloroplasts. Contemporary cyanobacteria have evolved as widely-diverse organisms in colonizing most aquatic and soil biotopes, where they face various environmental challenges and competition or symbiosis with other organisms. Cyanobacteria exhibit a wide morphological diversity (unicellular/multicellular, cylindrical/spherical shapes) and many species differentiate specialized cells for growth and survival under adverse conditions. They convert captured solar energy at high efficiencies, to fix an enormous amount of carbon from CO2 into a huge biomass that sustains a large part of the food chain, and they tolerate high CO2 content in gas streams. They also synthesize a vast array of biologically active metabolites with great interests for human health and industries. Hence, they are viewed as promising “low-cost” cell factories for the carbon-neutral production of chemicals, thanks to their simple nutritional requirements, their metabolic robustness and plasticity, and the powerful genetics of some model strains.