Changes in volatile production during interspecific interactions between four wood rotting fungi growing in artificial media

Effects of volatile organic compounds (VOCs) produced during interspecific mycelial interactions were examined by measuring extension rate of ‘target’ fungi growing in agar plates taped above two interacting mycelia – Bjerkandera adusta, Hypholoma fasciculare, Stereum gausapatum and Trametes versicolor in all combinations. Extension rates of T. versicolor, S. gausapatum and H. fasciculare above self-pairings were not significantly different (P > 0.05) to growth above agar controls, but the extension rate of B. adusta was significantly (P ≤ 0.05) greater. Extension rates of T. versicolor and B. adusta were often significantly greater above inter-specific interactions and above other species compared with growth above self or agar controls. VOC production was quantified and qualified, by gas chromatography–mass spectrometry (GC/MS), over the course of interactions with T. versicolor replacing S. gausapatum, deadlocking with B. adusta and replaced by H. fasciculare. VOC production was species- and interaction-specific. It varied over the time course of interactions, and changes in production were correlated with production of pigments in interactions involving S. gausapatum. VOCs included 3 monoterpenes, benzoic acid, alkenols of different chain lengths, two long-chain hydrocarbons and a quinolinium-like compound. Their possible roles are discussed.