Insight into lichen physiology and biochemistry following exposure to rapid depressurization, vacuum conditions, and ionizing radiation-does the anhydrobiotic state and melanization protect lichens against cytotoxicity?

Lichens are more vulnerable to rapid depressurization and radiation when hydrated, but melanized thalli show enhanced recovery, highlighting protective roles of desiccation tolerance and melanin.

• Why it matters: Understanding lichen resilience under extraterrestrial-like stress conditions is crucial for assessing their survival potential in space environments and for astrobiological research.
• What they did: The study exposed Cetraria aculeata in active and anhydrobiotic states, including melanized and pale forms, to simulated vacuum, depressurization, and radiation, analyzing cellular and biochemical responses.
• The result: Findings reveal that membranes are primarily damaged non-oxidatively during desiccation, but recovery of photosynthesis and chlorophyll occurs, especially in melanized lichens, indicating their potential for resilience in extreme conditions.