The production of effective inoculants for agricultural use presumes a sensitive method for detection of bacteria used as inoculants. The competitive ability of the introducing strain against indigenous rhizobia and other soil organisms, is often necessary to re-inoculate for soil management to encourage the development of an effective symbiosis? Until recently the agglutination and immunodiffusion tests (AGDDT) have been the ones most commonly used for Rhizobium strain identification. In the present studies a rapid sensitive method of enzyme-linked immunosorbent assay (ELISA) was developed for serotyping of Rhizobium isolates was used for serological identification of fast- and slow-growing Rhizobium strains belonging to different species. For the study the homologous antisera was raised against Rhizobium of Dalbergia latifolia (TKDL2) strain. ELISA was also successfully used for strain identification in mixed inoculated plants. The enzyme-linked immunosorbent assay (ELISA) technique for examining the serological diversity of fast growing rhizobia of twenty one isolates (diverse strains) from three countries were examined with homologous antisera. Some strains showed no antigenic relatedness with each other while others were closely related, and some showed a greater affinity with the Rhizobia of Dalbergia latifolia strain than with other strains. All of the strains showed antigenic homology to an isolate from USDA 4128 (Rhizobium galegae) and Leucaena leucocephala sp., these patterns of relatedness and diversity clearly demonstrated the utility of the DAC ELISA method.
