Abstract
Several rhizobial strains were isolated from Phaseolus coccineus root nodules and were determined to be Rhizobium leguminosarum biovar phaseoli strains after reinfection of the same host plant. These strains were characterized by cultural procedures (growth on different carbon sources and intrinsic antibiotic resistance) and electrophoretic procedures (sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total proteins). Our results showed that these rhizobia are very similar to each other, especially in their electrophoretic protein banding patterns, suggesting that they might belong to isolated populations.