Application of fungal volatile organic compounds for enhancing plant growth and controlling plant pathogens

Volatile organic compounds (VOCs) play important and diverse roles in the environment. In complex ecological communities, they mediate inter-organismal communication. The physical properties of VOCs enable them to diffuse through the air and impact above-ground plant parts, as well as affect underground plant parts in gas-filled pores in the soil. Many microbial VOCs stimulate plant growth and/or inhibit the growth of plant pathogens. Because VOCs do not rely on direct contact between the biocontrol organism and the pathogen, they can work at a distance. However, VOCs easily dissipate into the atmosphere, and the physiological effects of VOCs are highly concentration-dependent, which pose challenges for controlled applications. Currently, their greatest utility is for storage pathogens and greenhouse crops. This review summarizes important findings about fungal VOCs from an agricultural perspective, giving examples of plant growth promotion and the inhibition of plant pathogens while also highlighting the challenges that accompany attempts to harness VOCs activity for agricultural productivity.