Specificity of the Rhizobium-legume symbiosis obtained after mutagenesis in pea (Pisum sativum L.).

Within a set of 13 induced symbiotic pea (Pisum sativum L.) mutants, two distinct mutated genes sym25 and sym26, selected for ineffective nodulation have been counteracted in their effect by Rhizobium strains 254 and 94 respectively, thereby establishing an N2 -fixing symbiosis. This suggests that mutagenesis can be a helpful tool in creating specificity systems such as those described in centres of origin and diversification of legume species.