Class-wide genomic tendency throughout specific extremes in black fungi

Abstract

The classes Dothideomycetes and Eurotiomycetes include constitutively melanized fungi adapted to extreme conditions and they are widely distributed in diverse hostile habitats worldwide. Yet, despite the growing interest in these fungi, there is a considerable gap of knowledge on their functionality. Their genomic analysis is still in its infancy and the possibility to understand their adaptive strategies and exploit their potentialities in bioremediation is very limited. Here, we supply a genome catalog of 118 black fungi, encompassing different ecologies, phylogenies and lifestyles, as a first example of a comparative genomic study at high level of diversity. Results indicate that, as a rule, Dothideomycetes show more variable genome size and that larger genomes are associated with harshest conditions; low temperature tolerance and DNA repair capacity are overrepresented in their genomes. In Eurotiomycetes high temperature tolerance and capacity to metabolize hydrocarbons are more frequently present and these abilities are positively correlated with the human presence. The genomic features are consistent with the prevalent ecologies in the two classes. Indeed, Dothideomycetes are more common in cold and dry environments with high capacity for DNA repair being consistent with the normally highly UV-impacted conditions in their habitats; in contrast, Eurotiomycetes spread mainly in hot human-impacted sites with industrial pollution. Mean annual temperature and isothermality are positively correlated with tolerance to high temperatures in Dothideomycetes, suggesting that, despite their preference for the cold, they are potentially equipped to survive even when temperatures rise due to the global warming.