Comparative eco-physiology revealed extensive enzymatic curtailment towards virulence factors and strong conidial resilience of the bat pathogenic fungus Pseudogymnoascus destructans. Comparative eco-physiology of Pseudogymnoascus spp.

The genus Pseudogymnoascus encompasses soil psychrophilic fungi living also in caves. Some of them are opportunistic pathogens; nevertheless, they do not cause outbreaks. Pseudogymnoascus destructans is the causative agent of the white-nose syndrome, which is decimating cave-hibernating bats across the Nearctic. Here we used comparative eco-physiology by contrasting the enzymatic potential and conidial resilience to stressful conditions of P. destructans with that of a phylogenetically diverse set of cave fungi, including Pseudogymnoascus spp., dermatophytes and outdoor saprotrophs. Cave fungi represent a metabolically well-defined group with low tolerance to high temperatures and UV light, which restricts them to the cave environment. P. destructans exhibits strong specialization for pathogenicity that is manifested by losses of redundant metabolic variability and the accentuation of features linked with virulence. We suppose that lipases are the most important enzymes allowing fungal hyphae to digest and invade the skin, forming cup-like erosions. We detected growth medium alkalization due to urea degradation by P. destructans, so environmental alkalization should also be considered a potent virulence factor. The strong resilience of P. destructans conidia adverts to the possibility of their long-term persistence on the body surface of bats and the spreading of the disease during their active season.