Resource capture and competitive ability of non-pathogenic Pseudogymnoascus spp. and P. destructans, the cause of white-nose syndrome in bats

Michael B Wilson,Benjamin W Held,Christine E Salomon,Robert A Blanchette,Amanda H Freiborg,Michelle L Baker

doi:10.1371/journal.pone.0178968

Abstract

White-nose syndrome (WNS) is a devastating fungal disease that has been causing the mass mortality of hibernating bats in North America since 2006 and is caused by the psychrophilic dermatophyte Pseudogymnoascus destructans. Infected bats shed conidia into hibernaculum sediments and surfaces, but it is unknown if P. destructans can form stable, reproductive populations outside its bat hosts. Previous studies have found non-pathogenic Pseudogymnoascus in bat hibernacula, and these fungi may provide insight into the natural history of P. destructans. We compared the relatedness, resource capture, and competitive ability of non-pathogenic Pseudogymnoascus isolates with P. destructans to determine if they have similar adaptations for survival in hibernacula sediment. All non-pathogenic Pseudogymnoascus isolates grew faster, utilized a broader range of substrates with higher efficiency, and were generally more resistant to antifungals compared to P. destructans. All isolates also showed the ability to displace P. destructans in co-culture assays, but only some produced extractible antifungal metabolites. These results suggest that P. destructans would perform poorly in the same environmental niche as non-pathogenic Pseudogymnoascus, and must have an alternative saprophytic survival strategy if it establishes active populations in hibernaculum sediment and non-host surfaces.

Highlights

White-nose syndrome (WNS) is an invasive mycosis of hibernating bats caused by the psychrophilic fungus Pseudogymnoascus destructans, formerly Geomyces destructans [1,2,3]
White-nose syndrome has spurred research on the microbiome of bat hibernacula to better understand the biology of P. destructans
Many Pseudogymnoascus and Geomyces species have been discovered in WNS-positive hibernacula [16,31], but our Pseudogymnoascus isolates represent the Soudan Iron Mine (SM) fungal community prior to the invasion of P. destructans

Summary

Introduction

White-nose syndrome (WNS) is an invasive mycosis of hibernating bats caused by the psychrophilic fungus Pseudogymnoascus destructans, formerly Geomyces destructans [1,2,3]. P. destructans was completely unknown before the mass mortality of North American bats began in 2006, but is recognized as an invasive pathogen from Europe [4,5,6]. While P. destructans does not cause mass mortality in its native range [5], up to 6.7 million North American bats died of WNS by 2012 [7] with the possibility of widespread or local extinctions in the future [8,9]. At least seven North American bat species are affected by WNS throughout 29. Resource capture and competitive ability of non-pathogenic Pseudogymnoascus spp. and P. destructans.

Methods

Results

Conclusion