Volatile profiles of fungi--chemotyping of species and ecological functions.

Fungi emit a large spectrum of volatile organic compounds (VOCs). In the present study, we characterized and compared the odor profiles of ectomycorrhizal (EM), pathogenic and saprophytic fungal species with the aim to use these patterns as a chemotyping tool. Volatiles were collected from the headspace of eight fungal species including nine strains (four EM, three pathogens and two saprophytes) using the stir bar sorptive extraction method and analyzed by gas chromatography-mass spectrometry (GC-MS). After removal of VOCs released from the growth system, 54 VOCs were detected including 15 novel compounds not reported in fungi before. Principle component and cluster analyses revealed that fungal species differ in their odor profiles, particularly in the pattern of sesquiterpenes. The functional groups and species could be chemotyped by using their specific emission patterns. The different ecological groups could be predicted with probabilities of 90-99%, whereas for the individual species the probabilities varied between 55% and 83%. This study strongly supports the concept that the profiling of volatile compounds can be used for non-invasive identification of different functional fungal groups.