Exoplanets - a Unipd Research

19.02.2024

Scientists are even closer in their search for life in the universe, thanks to a study by Prof Nicoletta La Rocca of the Department of Biology at the University of Padua. The work was made possible with multidisciplinary coordination of research groups focused on biology, bioinformatics, engineering, and astronomy.

Published in Frontiers in Plant Science, the study Transcriptomic and photosynthetic analyses of Synechocystis sp. PCC6803 and Chlorogloeopsis fritschii sp. PCC6912 exposed to an M-dwarf spectrum under an anoxic atmosphere demonstrates how cyanobacteria exposed to simulated conditions of exoplanets with an anoxic atmosphere and illuminated by a red dwarf star show good growth and photosynthesis capacity thanks to specific gene regulation.

Cyanobacteria are microorganisms with a very ancient origin. They appeared about 3.5 billion years ago and developed a revolutionary metabolic process, oxygenic photosynthesis, which profoundly changed the Earth's atmosphere.

Scientific Director of two projects financed by the Italian Space Agency, Prof La Rocca explains,

“We study the acclimatization capabilities of two cyanobacteria, Chlorogloeopsis fritschii sp. PCC6912, capable of using far-red light in addition to visible light for its growth, and Synechocystis sp. PCC6803, capable of using only visible light to grow. Surprisingly, the oxygen-free atmosphere did not significantly impact the response of the two organisms. The results show how both organisms are predisposed to anoxia and how simulated red dwarf star light can be harvested effectively and is sufficient to maintain a metabolism like that to which the organisms are exposed to sunlight. Unlike Synechocystis sp. PCC6803, Chlorogloeopsis fritschii sp. PCC6912 proved capable of using far-red light and showed the ability to acclimatize to the simulated light of a red dwarf star through a specific response, encoded in the organism's DNA."

The results of this study prove the adaptability and versatility of cyanobacteria and give important information on the potential contribution of far-red photosynthesis to the oxygenation of Earth's primordial atmosphere and are a positive signal for the search for life in exoplanets orbiting red dwarf stars.