Isolation and molecular characterization of root nodules bacteria on inoculated Bambara groundnut (Vigna subterranea (L) Verdc) Accessions

Abstract

Abstract Soils in the tropics have often shown diverse reduction in the population of bacteria due to the pressure on the agricultural system with the nature of the climatic conditions, which eventually affect soil health. High priority has been placed on rhizobia inoculants over the inorganic fertilizer by farmers and this has led to the onset of great research on tropical rhizobia strains. In this study, bacteria isolates from root nodules of inoculated Bambara groundnut (BGN) were characterized using 16S rRNA gene, nitrogen fixing gene (nifH) and nodulating gene (nod A and nodC ). The result of the 16S rRNA revealed that the root of BGN are mostly associated with Bradyrhizobium spp (B. spp), which include: B. diazoefficiens, B. japonicum and Rhizobium spp in the screenhouse. The nifH, nod A and nod C gene analysis revealed that Streptomyces bacillaris, Pseudomonas knackmussi, B. ekanii, Sinorhizobium meliloti, Mesorhizobium spp, Bradyrhizobium spp and Rhizobium spp were isolated from the field in two locations (Ibadan and Ikenne). The rhizobia isolates have been previously confirmed to be playing an important role in nodulation and nitrogen fixation of BGN. The result of the study, therefore, revealed the isolation of bacteria species from the root nodules of BGN accessions using molecular techniques.