Fungal volatile organic compounds.

Volatile organic compounds (VOCs) are carbon-based, low molecular weight compounds that easily enter the gaseous state due to their low boiling point and high vapor pressure. Biogenic VOCs are those metabolites made by or associated with living systems. In nature, these VOCs are detected as combined mixtures of varying amounts and concentrations of alcohols, aldehydes, esters, ketones, modified amino acids, furans, terpenes, thiols and their derivatives. Many organisms use volatile compounds for signaling and defense, where they are variously called 'semiochemicals', 'infochemicals', 'allelochemicals' or 'pheromones'. In this Primer, we discuss what it means to be a VOC, especially with regard to VOC production by fungi.