Ecology and Physiology

Abstract

The subnivean environment represents a habitat of snow mold fungi where their resources, i.e., living plant tissues, are limited and do not increase. The fungi have adopted two major contrasting life history strategies in terms of resource utilization: facultative snow mold fungi can become abundant even without snow cover, and obligate snow mold fungi require snow cover for activity. Some obligate snow mold fungi particularly ascomycetes share plant tissues with other genotypes of the same species and coexist, while basidiomycetous obligate snow mold fungi often exclude even other genotypes of the same species and monopolize resources by individualism. The duration of snow cover is, of course, critical to snow mold fungi for survival and propagation, but the beginning of persistent snow cover and its end are other important issues. Snow mold fungi developed diverse life history strategies to adapt to the predictability of snow cover, which is typically represented by the germination rate and the size of sclerotia. Snow mold fungi also exhibit diverse metabolic reactions to tolerate freezing stress by producing antifreeze proteins, exhibiting osmophily, and altering fatty acid composition. Some snow mold fungi protect themselves from freezing by colonizing deeper into plant tissues.