From the Lab Bench to the Forest: Ecology and Defence Mechanisms of Volatile-Mediated ‘Talking Trees’

Transfer of information is important for almost all biotic interactions, but has received less attention in plants. Volatile organic chemicals (VOCs) emitted from floral tissues and green tissues of plants affect how plants interact with each other (informally termed ‘plant communication’), with mutualists such as pollinators and with enemies such as herbivores. In this chapter, we give an overview of VOC-based plant communication, in which plants that eavesdrop on VOC signals emitted from neighbouring herbivore-damaged plants increase their defence. While historically controversial, recent research has begun to establish the details of these interactions in various plant systems, including the identity of the VOC signal, the mechanism of VOC perception and the transduction pathways that link VOC perception to a defensive response. At the same time, ecological studies have begun to establish the evolutionary drivers of plant communication. Key insights from these studies are that these responses are kin-specific, memorable and mediated by known internal defence signals and epigenetic regulations in plant cells. Moving forward, studies that connect our increasing understanding of the mechanisms of plant–plant communication with their ecological consequences will help determine the importance of this type of defensive induction as well as the targets of selection within the plant–plant communication apparatus.