Phenotype profiling of white-nose syndrome pathogen Pseudogymnoascus destructans and closely-related Pseudogymnoascus pannorum reveals metabolic differences underlying fungal lifestyles

Abstract

<ns4:p> <ns4:bold>Background:</ns4:bold> <ns4:italic>Pseudogymnoascus</ns4:italic> <ns4:italic>destructans</ns4:italic> , a psychrophile, causes bat white-nose syndrome (WNS). <ns4:italic>Pseudogymnoascus pannorum</ns4:italic> , a closely related fungus, causes human and canine diseases rarely. Both pathogens were reported from the same mines and caves in the United States, but only <ns4:italic>P. destructans</ns4:italic> caused WNS. Earlier genome comparisons revealed that <ns4:italic>P. pannorum</ns4:italic> contained more deduced proteins with ascribed enzymatic functions than <ns4:italic>P. destructans</ns4:italic> . </ns4:p> <ns4:p> <ns4:bold>Methods:</ns4:bold> We performed metabolic profiling with Biolog PM microarray plates to confirm <ns4:italic>in silico</ns4:italic> gene predictions. </ns4:p> <ns4:p> <ns4:bold>Results:</ns4:bold> <ns4:italic>P. pannorum</ns4:italic> utilized 78 of 190 carbon sources (41%), and 41 of 91 nitrogen compounds (43%) tested. <ns4:italic>P. destructans</ns4:italic> used 23 carbon compounds (12%) and 23 nitrogen compounds (24%). <ns4:italic>P. destructans</ns4:italic> exhibited more robust growth on the phosphorous compounds and nutrient supplements (83% and 15%, respectively) compared to <ns4:italic>P. pannorum</ns4:italic> (27% and 1%, respectively.). <ns4:italic>P. pannorum</ns4:italic> exhibited higher tolerance to osmolytes, pH extremes, and a variety of chemical compounds than <ns4:italic>P. destructans</ns4:italic> . </ns4:p> <ns4:p> <ns4:bold>Conclusions:</ns4:bold> An abundance of carbohydrate degradation pathways combined with robust stress tolerance provided clues for the soil distribution of <ns4:italic>P. pannorum</ns4:italic> . The limited metabolic profile of <ns4:italic>P. destructans</ns4:italic> was compatible with <ns4:italic>in silico</ns4:italic> predictions of far fewer proteins and enzymes. <ns4:italic>P. destructans</ns4:italic> ability to catabolize diverse phosphorous and nutrient supplements might be critical in the colonization and invasion of bat tissues. The present study of 1,047 different metabolic activities provides a framework for future gene-function investigations of the unique biology of the psychrophilic fungi. </ns4:p>