Cellular Responses of the Lichen Circinaria gyrosa in Mars-Like Conditions

作者：Rosa de la Torre Noetzel, Ana Z. Miller, José M. de la Rosa Arranz, Claudia Pacelli, Silvano Onofri, Leopoldo G. Sancho, Beatriz Cubero, Andreas Lorek, David Wolter, Jean Pierre de Vera · 发表于：Frontiers in Microbiology · 年份：2018 · DOI：10.3389/fmicb.2018.00308 · 被引用次数：33 · 研究领域：Lichen and fungal ecology、Biocrusts and Microbial Ecology、Planetary Science and Exploration

Lichens are extremely resistant organisms that colonize harsh climatic areas, some of them defined as “Mars-analog sites”. There still remain many unsolved questions as to how lichens survive under such extreme conditions. Several studies have been performed to test the resistance of various lichen species under space and in simulated Mars-like conditions. The results led to the proposal that Circinaria gyrosa (Lecanoromycetes, Ascomycota) is one of the most durable astrobiological model lichens. However, although C. gyrosa has been exposed to Mars-like environmental conditions while in a latent state, it has not been exposed in its physiologically active mode. We hypothesize that the astrobiological test system “Circinaria gyrosa”, could be able to be physiologically active and to survive under Mars-like conditions in a simulation chamber, based on previous studies performed at dessicated-dormant stage under simulated Mars-like conditions, that showed a complete recover of the PSII activity (Sanchez et al., 2012). Epifluorescence and confocal laser scanning microscopy showed that living algal cells were more abundant in samples exposed to niche conditions, which simulated the conditions in micro-fissures and micro-caves close to the surface that have limited scattered or time-dependent light exposure, than in samples exposed to full UV radiation. The medulla was not structurally affected, suggesting that the niche exposure conditions did not disturb the lichen thalli structu...