Facteurs Nod et Myc : des molécules signal au champ pour un gain de productivité des cultures

In the 1970s, Pierre Boistard and Jean Dénarié, then researchers at INRA Versailles, formulated an ambitious project: to understand the fundamental genetic mechanisms of interactions between plants and micro-organisms. At a time marked by the first oil crises and the rise of biotechnologies, the symbiotic fixation of atmospheric nitrogen by cereals held out the promise of attracting a great deal of support. Investment in this area of research will have a major scientific impact, renewing the approach to interactions between plants and micro-organisms. If the promise of nitrogen fixation by cereals has not been fulfilled, major applications will emerge. In the 1990s, Jean Dénarié's team at LIPM2 (INRA/CNRS in Toulouse) discovered lipochito-oligosaccharides (LCOs). They demonstrated that these signaling molecules, “called Nodulation Factors (or Nod-LCOs)”, produced by rhizobia trigger the nodulation process in leguminous plants. In the 2010s, the same team demonstrated that certain fungi (arbuscular mycorrhizal fungi and ecto mycorrhizal fungi) also produce LCOs, enabling them to establish symbiotic relationships with plants. Researchers have also observed that LCOs can stimulate root system development.These discoveries have been patented by LIPM's supervisory bodies (CNRS and INRA). Exclusive licenses have been granted to an industrial player who has developed products that are now used in many countries. This industry player has observed that during field trials LCO-based biostimulants increase yields by around 3%. Nod-LCOs are used on 3 million hectares for legumes, while Myc-LCOs are used on 17 million hectares, mainly for corn.