ABSTRACT
Actually, in Republic of Congo, rhizobia have poorly
phenotypically and biochemically characterized. This study aimed to
characterize native rhizobia. Rhizobia strains were isolated using nodule roots
collected on Milletia laurentii, Acacia spp., Albizia lebbeck, and Vigna unguiculata. The strains isolated
were characterized microbiologically, biochemically, physiologically, and
molecularly identified using 16S rRNA method. The results reported in this
study are only for six strains of all 77 isolated: RhA1, RhAc4, RhAc15, RhAc13,
RhW1, and RhV3. All native strains were positive to urease activity, negative
to cellulase and pectinase activity except for one isolate that showed a
positive cellulase activity. Moreover, isolates have grown at 12% of NaCl. On
different effects of temperatures, isolates were able to grow up to 44°C and showed good growth at pH from 7 to 9 and
the ability to use ten different carbon hydrates sources. The strains were
identified as Rhizobium tropici, Rhizobium sp., Mesorhizobium sp. Bradyrhizobium
yuanmingense and Bradyrhizobium
elkanii. The phylogenetically analysis of the 16S rRNA genes, using a
clustering method, allowed us to have a history that is both ancient and stable
of four clades among genes with similar patterns. Expanding our awareness of
the new legume-rhizobia will be a valuable resource for incorporating an alternative
nitrogen fixation approach to consolidate the growth of legumes. These germs
can be used in Congolese agriculture to improve yield of crops.