Meeting Abstract

10.3  Wednesday, Jan. 4  Temperature-dependent growth performance of Geomyces destructans>, the fungus associated with white-nose syndrome in bats BOYLES, J.G.*; VERANT, M.L; WALDREP, JR., W.; WIBBELT, G.; BLEHERT, D.S.; Univ. of Tennessee, Knoxville; Univ. of Wisc, Madison; Univ. of Chicago; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; USGS National WIldlife Health Center, Madison, Wisconsin jgboyles@utk.edu

White-nose syndrome (WNS) has devastated populations of cavernicolous bats in eastern North America. The fungus Geomyces destructans (Gd) is the likely causative agent, but gaps remain in our knowledge of the basic biology of Gd. As a psychrophilic microorganism, temperature restrictions limit active growth of Gd to cold environments, but only cursory examinations of temperature-dependent growth have been completed to date. Infection with Gd causes high mortality in North American bats, but does not apparently negatively impact European bats. Thus, we grew two isolates of Gd, one North American and one European, on Sabouraud Dextrose agar at nine temperatures from 0 to 22°C. For each temperature tested, we measured the area of each of 21 colonies weekly for 6 weeks. We then described the performance curve of each isolate using an information-theoretic approach to distinguish among a set of seven candidate functions. Analyses indicated two curves, one for each isolate, better describe the data than does a single curve for all data, suggesting important differences in the temperature-dependent growth of the two isolates. The optimal temperature for growth was estimated at 13-14°C for both isolates, but the North American isolate grew 1.5 to 35 times faster across the range of temperatures measured. Visual examination of the colonies indicated that morphologies varied across temperatures with the colonies grown at temperatures ≥12 °C exhibiting properties indicative of stress (e.g. fragmentation of hyphae and production of chlamydospores).