Aroma profile of the Australian truffle-like Fungus Mesophellia glauca

The Australian truffle-like fungus Mesophellia glauca is a common mycorrhizal associate of eucalypt trees and other woody shrubs. Its fruit-bodies also provide an important food resource for a variety of ground dwelling marsupials, including the long-nosed potoroo (Potorous tridactylus) and the Tasmanian bettong (Bettongia gaimardi). At maturity the fruit-bodies of M. glauca produce pungent aromas which are superficially similar to those found in the European black truffle (Tuber melanosporum). These aromas serve to attract the fungus-feeding animals. A combination of simultaneous distillation extraction with GC-MS, static and dynamic headspace GC and GC-olfactometry was used to determine the aroma profile of M. glauca. The major components of the aroma of this fungus included, 1-octen-3-ol, 1-hexen-3-ol, 1,3-octadiene, 1-octene, hexanol, and hexan-3-ol. In the field, wildfires have been found to trigger increased foraging of marsupials for M. glauca. Comparison of fruit-bodies collected from recently burned and unburned forest indicated differences in aroma profile: fruit-bodies from burned sites had less of the more volatile constituents. A similar effect was reproduced when fruit bodies from an unburnt site were subjected to 60°C heat for 30min. However there was a major difference between the fire and heat treated fruit-bodies , with high levels of monoterpenes found in the former samples. These differences suggest that in addition to a heating effect caused by fire, other mechanisms contributing to changes in the aroma profile of fruit-bodies in burned habitats. While currently unknown, perhaps these mechanisms relate to physiological changes in the associated host plant.