The power of communication: biogenic volatile organic compound-mediated interactions in land plants and marine phytoplankton

In this chapter, we summarize current knowledge on the diverse ecological functions of biogenic volatile organic compounds (BVOCs) in biotic interactions among living organisms of both terrestrial and marine habitats, at the individual and community levels. Research on the regulatory ecology of BVOCs in these systems shows how these compounds are crucial determinants of the “eco-active chemosphere” (i.e., the ecological environmental interface where multiorganisms interactions are chemically mediated) of both land plants and phytoplankton. Beyond the plant-insect communication mediated by BVOCs, it is becoming clear that volatiles act as fundamental chemical mediators in plant-microorganism interactions, particularly with fungi or bacteria. Moreover, research on the role of BVOCs in aquatic systems has been poorly explored, while the ecological function of BVOCs as crucial chemical cues is emerging also for this environment. These aspects are described in relation to exemplary multiorganism systems that are critical in terrestrial or marine habitats: (1) on land, the aboveground plant-phytopathogen and (2) the belowground plant-beneficial microbiome systems; (3) in water, the phytoplankton-marine communities’ system. We highlight how different mechanisms and processes driven by BVOCs are activated depending on the form of associations between organisms (detrimental vs beneficial). Indeed, BVOCs may have either beneficial or adverse effects on the receiver organism by playing a direct (antimicrobial activity and allelopathy) or indirect (induced resistance) defensive role, and in mutualistic associations by acting as growth-promoting effectors or stress mitigators. We conclude with novel perspectives based on the meta-organism concept that could contribute to better characterizing the complexity of the ecological roles of BVOCs at different organism-microorganism interfaces.