IDENTIFICATION OF RHIZOBACTERIA IN A SOYBEAN CULTURE

The rhizosphere of crops has a high microbial activity because roots r elease substances which favour bacterial proliferation, The PGPR bacte ria (plant growth promoting rhizobacteria) represent a large subgroup of microorganisms colonizing rhizospheres and promoting plant developm ent through the production of metabolites. The aim of the present pape r was to gather information about plant-bacteria interaction in the rh izosphere of soybean. Bacterial density was 10(6) ufc/g dry soil, with a high stimulation of Gram negative bacteria which amount to 76% of t he total; 21% are Gram positive and 3% are Gram variable bacteria. The most abundant PGPR genera found within the Gram negative bacteria wer e Pseudomonas, Rhizobium, Azotobacter, Bradyrhizobium, Azospirillum an d others of great importance due to the role they play in soils.