An international group of biologists and astrobiologists has published the results of their research in npj Microgravity, which changes our understanding of the limits of life on Earth. The authors examined how the extremophile black fungus Rhinocladiella similis behaves when exposed to two key factors on Mars: high doses of UV-C radiation and magnesium perchlorates, salts that are found in large quantities in Martian soil.
In a 0.9% Mg(ClO₄)₂ solution, the fungal culture was irradiated with UV-C up to 0.4 kJ/m². Despite the powerful oxidative stress, R. similis retained approximately 80% of its viability, while the model “Martian” organism Exophiala 15Lv1 lost half of its colonies. Further tests showed steady growth of R. similis even at 250 mmol/L perchlorate — a concentration that mimics possible salt brines on Mars.
Explanation: Scientists exposed the fungus to a “cocktail” of Martian salt and strong ultraviolet light — conditions in which most microbes die. However, Rhinocladiella similis survived at a rate of nearly 80%, while the Martian fungus lost half of its cells. Even in a very salty solution, similar to possible Martian conditions, the black fungus grew calmly.
Using proteomics and metabolomics, scientists have discovered that the fungus transforms into a yeast form, increasing the production of antioxidant enzymes and protective melanin pigments. This “molecular shield” neutralizes active forms of oxygen and stabilizes cell membranes in a saline environment. This shield neutralizes harmful oxygen “garbage” and strengthens cell walls, making it resistant to salt and radiation.
Why is this important?
- Search for life: the results suggest which biomarkers Perseverance-2 or a future European rover could look for in perchlorate deposits.
- Planetary protection: Earth fungus with similar resilience are potentially capable of “attaching” themselves to equipment and colonizing Mars, so sterilization procedures will have to be reviewed.
- Space biotechnology: R. similis melanin pigments can serve as natural UV screens for future biopins, protecting living modules on Mars from radiation.
The study once again demonstrates that life on Earth already possesses the tools necessary to conquer the harshest niches of the Red Planet. It seems that humanity’s struggle for survival on Mars may gain an unexpected fungal ally.
The answer to the question, “Why should humanity even consider colonizing Mars and other planets?” can be found in our special analytical article, “Why do people need to inhabit space?”, which examines the scientific and economic arguments in detail.
