Yeasts in the Era of Astrobiological Research

Due to their extraordinary genetic and phenotypic plasticity, yeast and yeast-like fungi have been able to adapt and colonize a wide range of ecological niches. Pigmented and nonpigmented extremophilic yeasts have been discovered in areas on Earth characterized by physical and chemical conditions similar to those found in extraterrestrial environments. Thus, these "simple" eukaryotic life forms have evolved unique genetic, metabolic, and phenotypic characteristics for coping with extreme conditions, existing in both natural (polar continents, deep sea, stratosphere, etc.) and manmade environments such as the cleanrooms where spacecraft are built. This makes them ideal test organisms for astrobiology research. All of the results from the numerous experiments in which they have been tested are helping us to understand what to look for and where in space missions searching for signs of present and/or past life. Meanwhile, we must continue to explore the most inhospitable places on Earth to discover new promising extremophiles that could be used as model organisms for astrobiology research.