Communication in the Rhizosphere, a Target for Pest Management

Abstract

The industrial agriculture has given rise to an excessive use and misuse of agrochemicals causing environmental pollution. Therefore, it is urgent to find alternatives that are more environmentally friendly than chemical fertilizers and pesticides for disease control. The key to achieve successful biological control strategies is the knowledge of the ecological interactions that occur belowground. The rhizosphere constitutes a very dynamic environment harbouring the plant roots and many organisms. Plants communicate and interact with those organisms through the production and release of a large variety of secondary metabolites into the rhizosphere. Thus, they use these metabolites to defend themselves against soil-borne pathogens, which can adversely affect plant growth and fitness, but also to establish mutualistic associations with beneficial soil microorganisms. However, despite the importance of these plant-organism interactions the mechanisms regulating them remain largely unknown. We review here chemical communication that takes place in the rhizosphere between plants and other soil organisms, and the potential use of this molecular dialogue for developing new biological control strategies against deleterious organisms. We focus on the knowledge of the root parasitic weed germination stimulants – strigolactones – to develop more efficient control methods against this pest. Finally, we illustrate this with an exciting example: the use of the mutualistic arbuscular mycorrhizal symbiosis for controlling root parasitic weeds by reducing the production of strigolactones in the host plant.