Modification of symbiotic interaction of pea (Pisum sativum L.) and Rhizobium leguminosarum by induced mutations

TLDR: The results of the present investigation show that pea mutants which are modified in their symbiosis with Rhizobium leguminosarum, can readily be obtained and the significance of such mutants for fundamental studies of the legume-RhZobium symbiosis and for applications in plant breeding is discussed.

Abstract: In pea (Pisum sativum L.), mutants could be induced, modified in the symbiotic interaction withRhizobium leguminosarum. Among 250 M2-families, two nodulation resistant mutants (K5 and K9) were obtained. In mutant K5 the nodulation resistance was monogenic recessive and not Rhizobium strain specific. Out of 220 M2-families one mutant nod3 was found which could form nodules at high nitrate concentrations (15 mM KNO3). This mutant nodulated abundantly with severalRhizobium strains, both in the absence and presence of nitrate. Probably as the result of a pleiotropic effect, its root morphology was also changed. Among 1800 M2-families, five nitrate reductase deficient mutants were obtained and one of them (mutant E1) was used to study the inhibitory effect of nitrate on nodulation and nitrogen fixation.