Cyanobacteria from extreme deserts to space

The development of space technology makes possible the exposure of organisms and molecules to the space environ-ment by using the ESA Biopan and Expose facilities and NASA nanosatellites; the aim is to decipher the origin, evolu-tion and distribution of life on Earth and in the Universe. The study of microbial communities thriving in lithic habitats in cold and hot deserts is gathering appreciation when dealing with the limits of life as we know it, the identification of biosignatures for searching life beyond Earth and the validation of the (litho)-Panspermia theory. Cyanobacteria of the genus Chroococcidiopsis dominate rock-dwelling communities in extreme deserts that are considered terrestrial ana-logues of Mars, like the Dry Valleys in Antarctica, the Atacama Desert in Chile or the Mojave Desert in California. The extraordinary tolerance of these cyanobacteria towards desiccation, ionizing and UV radiation makes them suitable ex-perimental strains which have been already used in astrobiological experiments and already selected for future space missions. Evidence gained so far supports the use of desert cyanobacteria to develop life support systems and in-situ resource utilization for the human space exploration and settlement on the Moon or Mars.