SYSTEM BIOLOGY AND ECOLOGY OF MICROCOLONIAL FUNGI

Black, rock inhabiting fungi are the most stress resistant eukaryotic organisms known today. They inhabit bare rock surfaces in hot and cold deserts of all regions on the earth. They are characteristic members of the epi- and endolitic microbial community even in the Arctic and Antarctic. Recent experiments showed that their stress resistance against solar radiation, radioactivity, desiccation and oligotrophic conditions even allows them to survive in Outer Space and under Martian conditions. The ultimate target of the project is to get a deeper understanding of the ecology of black microcolonial fungi and to analyze the cellular mechanisms that are responsible for their enormous stress tolerance. Black fungi isolated from rocks in Polar regions and from the dry Mediterranean environment will be studied concerning their stress adaptations and their life strategies. The resistance of these fungi is analyzed based on studies of protein expression profiles for the first time: 2-dimentional protein gels with fluorescent staining (DIGE) and a gel-free approach using multiplexed relative protein quantification (iTRAQ) are used for protein expression studies. RNA qunatification allows monitoring of the viability and of the changes between dormancy and activity of the fungi under various environmental conditions simulated in a climate chamber and in the Mars simulation chamber of the German Aerospace Center. Studying the proteome of black fungi is an absolute innovation in the field of black fungi research and understanding their ecology and stress tolerance is expected to be of broad interest for (a) biotechnological applications (cold / heat tolerant proteins and enzymes), (b) medical applications (new proteins as protectants in radiotherapies) and (c) regarding the effect of climate change to biology.

Black fungi are inhabitants of rock surfaces in all regions of the Earth; they are found in the Alps, on rock in the Arctic and Antarctica and in hot deserts and they survive even the condition found on Mars. The living conditions of those fungi are extreme: lack of water, lack of nutrients, extreme temperatures and high UV radiations create an environment that is not tolerated by most other living organisms. However, the black fungi have special sets of proteins that enable them to survive extreme conditions. The fungi under investigation were isolated from Antarctica (Cryomyces sp., the cold fungus), from glacier water and hot tap water (Exophiala sp.) and from marble monuments in the Mediterranean (Coniosporium sp.). In contrast to other fungi that have to produce special proteins and other protective substances in order to survive in case of upcoming uncomfortable conditions, the black microcolonial fungi are basically able to survive stress and only need minor changes in the cell a molecular fine tuning to grow and survive. It is especially interesting that one and the same fungus can grow at 0C as well as at 45C. By other experiments that were carried out in collaboration with the German Aerospace Center in Berlin we were able to show that the black fungi are able to grow under Mars-like conditions. For this reason the fungi are of special interest for the field of exobiology, that is investigating the possibility of life on other planets. In the future black fungi can be possible sources for substances that help to shelter human cells against desiccation or damages caused by free radicals with applications in cosmetics and medicine.