Unbreakable: Bird's nest fungi tolerate extreme abiotic stresses

Abstract

While much of the literature focuses on plant and prokaryote tolerance towards abiotic stresses, environmental resistance by fungi remains understudied. Many fungi have traits that help them to tolerate extreme environmental perturbations. Bird's nest fungi produce ‘peridioles’ which consist of basidiospores, basidia, hyphae, and melanized walls, but their tolerance towards environmental stresses is currently unknown. We exposed the peridioles of three distantly related bird's nest fungi species (Cyathus poepigii, Crucibulum parvulum, and Nidularia pulvinata) to extremely high temperatures, extremely low temperatures, and prolonged ultraviolet (UV-C) radiation. The viability of bird's nest fungi peridioles declined after high heat treatments although all three species showed tolerance up to about 40 °C. In contrast, peridioles were unaffected by freezing or direct ultraviolet radiation. Although bird's nest fungi are not typically found under extreme conditions, three distantly related species germinated well following exposure to extreme environments for either 6 or 24 h. More research is needed to clarify whether other peridiole-producing fungi share this wide tolerance of harsh environmental conditions.