Due to their biochemical plasticity, plants produce a great variety of volatile organic compounds (VOCs), leading to the evolution of a complex signalling system in their ecosystem. In fact, plant-associated microbes and animals are able to modulate and decipher gaseous environmental cues during their ecological interactions. Some volatile molecules are signals or mediators of plant defences. Among them, several plant hormones (ethylene, salicylic acid and jasmonic acid derivatives) are crucial for the activation of defence responses, in some cases through the production and release of toxic or deterrent essential oils, alkaloids, terpenoids, sulfur- or cyanide-containing molecules. Other plant-derived volatile signals may result attractant or beneficial for insects and microbes, thus driving host-specific relationships, such as herbivory or symbiosis. Finally, third parties may recognize compounds originating from existing interactions between plants and other ecological actors to modulate their activity. This review aims at summarizing the main mechanisms underlying volatile signals-mediated interactions between species for the development of environmentally sustainable applications. To date, significant results have been achieved in the control of some pests and pathogens.This review explores the variety of plant gas emissions and of the ecological relations with microbes and insects mediated by such signals. Finally, some technologies are discussed, which make use of the specific plant emissions in agriculturally relevant applications.
Keywords: Volatile Organic Compounds, Inter-specific signalling, Plant defences, Pest control