The modulating effect of bacterial volatiles on plant growth: current knowledge and future challenges

Abstract

Bacteria interact with plants in many different ways. In recent years, bacterial production of volatiles has emerged as a novel process by which bacteria modulate plant growth. Exposure to the volatiles produced by certain bacterial strains has been shown to lead to up to 5-fold increased plant biomass or to plant death. Despite these drastic growth alterations, the elucidation of the molecules responsible, of the mechanism of perception by the plant and of the specific metabolic changes induced in planta is still in its infancy. This review summarizes the current knowledge and highlights future lines of research that should increase our knowledge of the volatile-mediated dialogue between bacteria and plants.

Figure 1. Bacterial volatile organic compounds modulate plant growth. In heterogeneous soils, microorganisms may produce effective concentrations of compounds with inhibiting (left) or improving (right) effects on plant productivity. The observed effects range from plant death to enhanced rooting and greater biomass. Few bioactive molecules have been identified from the complex blends of bacterial VOCs. The involvement of different physiological pathways (oval shapes; double arrows: crosstalk) has been suggested but needs further investigation. Question marks stress the lack of information on VOCs’ target tissues.