Despite the ubiquity and importance of ectomycorrhizal fungi to ecosystem function, our understanding of their functional ecology remains poor. The highly melanized and common ectomycorrhizal fungus, Cenococcum geophilum, is drought tolerant and abundant in water-stressed habitats, yet the responsible functional traits have not been identified. The production of melanin, a class of complex dark polymers found in fungal cell walls, may be a key functional trait to water stress tolerance. To test this hypothesis, we devised a series of experiments determining the effect of the melanin biosynthesis inhibitor, tricyclazole, on response to osmotic and desiccation stresses. Melanin inhibition only had negative effects on growth when C. geophilum isolates were subjected to osmotic and desiccation stress (-1.7MPa and desiccated) but not under control conditions (-0.01MPa and non-desiccated). This suggests that melanin production is an important functional trait that contributes to water stress tolerance of this cosmopolitan ectomycorrhizal fungus.
Bibliographical noteFunding Information:
Funding to CWF was provided by the Alfred P. Sloan Foundation and The College of Agriculture Sciences at the Pennsylvania State University. Funding to RTK was provided by the U.S. Department of Agriculture NIFA , the U.S. National Science Foundation , and Brigham Young University . We thank Professors Kazuhide Nara and Håkan Wallander for providing the Japanese and Swedish isolates of Cenococcum geophilum, respectively, and Michael Standing for the electron microscopy. We would also like to acknowledge the editor and two anonymous referees for providing helpful comments on a previous version of the manuscript.
Copyright 2013 Elsevier B.V., All rights reserved.
- Cenococcum geophilum
- Ectomycorrhizal fungi
- Functional traits
- Water stress tolerance