Volatile organic compounds in the interaction between plants and beneficial microorganisms

A growing population coupled with a higher demand for food is putting pressure on agriculture. The use of synthetic pesticides and chemical fertilizers allowed us to boost agricultural productions, but at a great environmental cost. Exploitation of beneficial microorganism (BM)-plant interactions has been proposed as an eco-friendly solution to improve plant resistance to stresses and to increase productivity sustainably. We provide an overview of scientific evidence that this positive interaction is often mediated also by the release of microbial Volatile Organic Compounds (mVOCs). A few mVOCs are reported to have a double, not mutually exclusive, positive effect on plants, as plant growth promoters, and/or inducers of resistance against biotic and abiotic stress factors. They may also alter plant VOCs indirectly improving plant performances. However, mechanisms and functions of mVOCs need deeper investigation. By understanding mVOC modes of action on plants, further tools for sustainably improving plant productivity in agro-ecosystems may become soon available.