Fungal volatile organic compounds and their role in ecosystems

All odorants are volatile organic compounds (VOCs), i.e., low molecular weight compounds that easily evaporate at normal temperatures and pressure. Fungal VOCs are relatively understudied compared to VOCs of bacterial, plant, or synthetic origin. Much of the research to date on fungal VOCs has focused on their food and flavor properties, their use as indirect indicators of fungal growth in agriculture, or their role as semiochemicals for insects. In addition, research into fungal volatiles has also taken place to monitor spoilage, for purposes of chemotaxonomy, for use in biofilters and for biodiesel, to detect plant and animal disease, for "mycofumigation," and with respect to plant health. As methods for the analysis of gas phase molecules have improved, it has become apparent that fungal VOC are more chemically varied and more biologically active than has generally been realized. In particular, there is increasing data that show that fungal VOCs frequently mediate interactions between organisms within and across different ecological niches. The goal of this mini review is to orchestrate data on fungal VOCs obtained from disparate disciplines as well as to draw attention to the ecological importance of fungal VOCs in signaling between different species. Technologies and approaches that are common in one area of research are often unknown in others, and the study of fungal VOCs would benefit from more cross talk between subdisciplines.