Characterization and genetics identification of Rhizobium isolates on common bean (Phaseolus vulgaris L.)

The work was carried out to characterize and identify bacteria belonging to Rhizobium genus isolated from 13 sampling areas in the provinces of Sancti Spiritus, Cienfuegos and Villa Clara. The morphological analysis was based on determining the differences of the colonies obtained from isolation, which evaluated the Gram stain, growth type, color, mucus production, edge and elevation. The genetic identification of isolates resulting from the morphological characterization was performed by gene sequencing of the 16S rRNA region. The results show a wide morphological diversity of native strains of Rhizobium and plant growth promoting rhizobacteria (PGPR) in the soils of the central region of Cuba, resulting in 65 initial colonies, from which 33 showed different characteristics in at least one parameter evaluated. From a total of 22 sequences analyzed in the genetic identification, six bacterial genera were obtained, in which the genus Rhizobium showed the variability of species. From eight sequences aligned, four species were identified, among them the first report of R. pisi for Cuba. These results demonstrate the wide genetic diversity of Rhizobium in central Cuba, which can be the basis for obtaining efficient strains for the inoculants performance.