Highlights • Mutants in Solanaceaous LysM receptors LYK10 are impaired in arbuscular mycorrhiza • LYK10 proteins have a high affinity for lipo-chitooligosaccharidic signal molecules • LYK10 promoter is expressed in arbuscule-containing cells in tomato roots • Solanaceaous LYK10 can restore nodulation in legumes mutated in their orthologs Summary Bacterial lipo-chitooligosaccharides (LCOs) are key mediators of the nitrogen-fixing root nodule symbiosis (RNS) in legumes.