ECOLOGICAL ADAPTATIONS OF LOW-TEMPERATURE PLANT-PATHOGENIC FUNGI TO DIVERSE WINTER CLIMATES

Most microorganisms cannot grow under snow, but the low-temperature tolerance of snow molds enables them to prevail in a nival habitat. Snow molds escape antagonism and competition by other microorganisms. Snow molds are divided into two categories: a) obligate snow molds that prevail exclusively in winter; and b) facultative snow molds that thrive during the growing seasons of their hosts and in winter. Most of the obligate snow molds are considered as opportunistic pathogens because of their requirement for persistent snow cover. Understanding how these microbes exploit the limited resources of host tissues and cope with the instability of the habitat is central to understanding the ecological constraints governing the prevalence and distribution of snow molds. This paper describes how snow mold fungi solve these problems.