Phosphate-solubilizing Pseudomonas putida can influence the rhizobia-legume symbiosis

Allfalfa and soybean are the most important leguminous plants in the agricultural system of the semiarid pampas of Argentina. The possible action of phosphate solubilizing bacteria on the leguminous-rhizobia symbiosis was studied since in this region the available phosphorus distribution is not uniform. The strains used were Sinorhizobium meliloti 3DOh13, a good solubilizer of iron and phosphorus for alfalfa, Bradyrhizobium japonicum TIIIB for soybean and two phosphorus-solubilizing strains of Pseudomonas putida (SP21 and SP22) for growth promotion treatments. Modification of shoot and root system dry weights occured in soybean but not in alfalfa in presence of Pseudomonas strains.