XVI International Botanical Congess

Rhizobium species form a symbiosis with leguminous plants. The bacteria fix nitrogen for the plant and the plant in turn provides the bacteria with energy and protection. To overcome low occupancy of inoculant strains in cultivation, a bean plant that limits nodulation to specific species of Rhizobium is needed. A mutant of P. vulgaris was found that restricts nodulation. Thirty-one strains of Rhizobium were noculated onto the mutant bean plant. Three of these strains were able to overcome the restriction and nodulate the mutant bean plant. Current studies are being done to determine the regulatory molecules involved n this relationship.