Browsing by Author "Ahiabor Benjamin D. K."

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    PCR assay for direct specific detection of Bradyrhizobium elite strain BR 3262 in root nodule extracts of soil-grown cowpea
    (Springer, 2017) Osei Ophelia; L. Jean; Araújo Simões; Zilli Jerri E.; Boddey Robert M.; Ahiabor Benjamin D. K.; Abaidoo R. C; Rouws Luc F. M.; 0000-0002-1235-2252
    Aims Successful inoculation of legume crops with rhizobia depends on dominating nodule occupancy with highly efficient strains. The aim of this study was to develop a rapid and reliable conventional PCR method ology to specifically detect an elite Bradyrhizobium strain in root nodule extracts from soil-grown cowpea plants. Methods The draft genome sequence of Bradyrhizobium pachyrhizi BR 3262 was compared to the closely related strain PAC 48T .BR 3262-specific regions were selected to design specific primer pairs, which were tested with respect to PCR amplification specificity and efficiency on extracted DNA, bacterial cells and root nodules from cowpea plants grown under gnotobiotic conditions and in soil. Results Eleven designed primer pairs were specific for BR 3262 amplification and two of them (pairs 2645 and 2736) were highly sensitive and selected for further analyses. Experiments with gnotobiotic and soil-grown plants showed that both primer pairs were suitable to reliably determine nodule occupancy and confirmed the competitiveness of strain BR 3262 in natural soil. Conclusions Primer pairs 2645 and 2736 are novel tools to accompany the fate of strain BR 3262 in inoculation experiments of cowpea in soil. This strategy should be applicable to other rhizobium/legume symbioses in the field.
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    Phylogenetically diverse Bradyrhizobium genospecies nodulate Bambara groundnut (Vigna subterranea L. Verdc) and soybean (Glycine max L. Merril) in the northern savanna zones of Ghana
    (FEMS Microbiology Ecology, 2022) Adjei Josephine A.; Aserse Aregu A.; Yli-Halla Markku; Ahiabor Benjamin D. K.; Abaidoo R. C
    A total of 102 bacterial strains isolated from nodules of three Bambara groundnut and one soybean cultivars grown in nineteen soil samples collected from northern Ghana were characterized using multilocus gene sequence analysis. Based on a concatenated sequence analysis (glnII-rpoB-recA-gyrB-atpD-dnaK), 54 representative strains were distributed in 12 distinct lineages, many of which were placed mainly in the Bradyrhizobium japonicum and Bradyrhizobium elkanii supergroups. Twenty-four of the 54 representative strains belonged to seven putative novel species, while 30 were conspecific with four recognized Bradyrhizobium species. The nodA phylogeny placed all the representative strains in the cosmopolitan nodA clade III. The strains were further separated in seven nodA subclusters with reference strains mainly of African origin. The nifH phylogeny was somewhat congruent with the nodA phylogeny, but both symbiotic genes were mostly incongruent with the core housekeeping gene phylogeny indicating that the strains acquired their symbiotic genes horizontally from distantly related Bradyrhizobium species. Using redundancy analysis, the distribution of genospecies was found to be influenced by the edaphic factors of the respective sampling sites. In general, these results mainly underscore the high genetic diversity of Bambara groundnut-nodulating bradyrhizobia in Ghanaian soils and suggest a possible vast resource of adapted inoculant strains.