Résumé
Nod factors are the rhizobial determinants of nodulation and host specificity in the legume-rhizobia symbiosis. These lipochitooligosacccharides (LCOs) are capable of eliciting various responses on the roots of legumes at pico-micromolar concentrations, suggesting that they are perceived by specific receptors in legumes. By using radiolabelled Nod factors we have been able to characterise different types of binding sites in legumes. The relevance of these Nod factors binding proteins as putative receptors will be discussed.