Diversity, geographical distribution and environmental adaptations of snow molds

In regions of cryosphere, plants dormant under snow are attacked by snow mold pathogens, which include various fungal taxa (mainly oomycetes, ascomycetes and basidiomycetes). These fungi are well adapted to the environment with ambient temperatures fluctuating at around 0 °C. Their cold adaptation mechanisms differ at the phylum level. Oomycetous and basidiomycetous snow molds avoid freezing by intracellular host infection and ice-binding protein, respectively. Osmophily is another mechanism to cope with freezing for the ascomycete, Sclerotinia borealis. Thus diverse fungal taxa evolved snow molds to adapt to nival environments, illustrating adaptive radiations by developing cold tolerance and selecting host organisms.