Browsing by Author "Boddey Robert M."

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    Bacteria related to Bradyrhizobium yuanmingense from Ghana are effective groundnut micro-symbionts
    (Elsevier, 2018) Osei Ophelia; Abaidoo R. C; Ahiabor Benjamin D.K.; Boddey Robert M.; Rouws Luc F.M.
    The identification of locally-adapted rhizobia for effective inoculation of grain legumes in Africa’s semiarid regions is strategic for developing and optimizing cheap nitrogen fixation technologies for smallholder farmers. This study was aimed at selecting and characterising effective native rhizobia, from Ghanaian soils for groundnut (Arachis hypogaea L.) inoculation. From surface-disinfected root nodules of cowpea and groundnut plants grown on farmers’ fields, 150 bacterial isolates were obtained, 30 of which were eventually found to nodulate groundnut plants. After testing the symbiotic potential of these isolates on groundnut on sterilized substrate, seven of them, designated as KNUST 1001–1007, were evaluated in an open field pot experiment using 15N labelled soil. Although 15N dilution analyses did not indicate differences among treatments in the proportion of nitrogen (N) derived from the atmosphere (%Ndfa), all seven strains increased total N derived from N2 fixation by inoculated groundnut plants as compared to the non-inoculated control. Inoculation with KNUST 1002 led to total N accumulation as high as that of the groundnut reference strain 32H1. Genetic characterisation of the isolates by sequence analysis of 16S rRNA gene, 16S – 23S rRNA intergenic transcribed spacer (ITS) region and nodC gene revealed that isolates KNUST 1003 and 1007 were related to Rhizobium tropici, a common bean symbiont. The other five isolates, including KNUST 1002 belonged to the Bradyrhizobium genus, being closely related to Bradyrhizobium yuanmingense. Therefore, this study revealed novel native Ghanaian rhizobia with potential for the development of groundnut inoculants
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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.