scholarly journals Biological nitrogen fixation and socioeconomic factors for legume production in sub-Saharan Africa: a review

2011 ◽  
Vol 31 (1) ◽  
pp. 139-154 ◽  
Author(s):  
Jonas. N. Chianu ◽  
E. M. Nkonya ◽  
F. S. Mairura ◽  
Justina. N. Chianu ◽  
F. K. Akinnifesi
Keyword(s):  
Nitrogen Fixation ◽  
Socioeconomic Factors ◽  
Biological Nitrogen Fixation ◽  
Sub Saharan Africa ◽  
Sub Saharan ◽  
Legume Production ◽  
Biological Nitrogen

scholarly journals Response of Cowpea, Soya Beans and Groundnuts to Non-Indigenous Legume Inoculants

2014 ◽  
Vol 3 (4) ◽  
pp. 84 ◽  
Author(s):  
Alice Mutiti Mweetwa ◽  
Malama Mulenga ◽  
Xaviour Mulilo ◽  
Munsanda Ngulube ◽  
John S. K. Banda ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Above Ground Biomass ◽  
Fresh Weight ◽  
Nodule Number ◽  
Ground Biomass ◽  
Randomized Design ◽  
Legume Production ◽  
Biological Nitrogen ◽  
Legume Inoculants

<p>The use of inoculants is a critical strategy in legume production. In Zambia, inoculants are particularly used for the production of non-promiscuous genotypes of soya beans, but rarely for cowpeas and groundnuts. This study evaluated the response of soya beans, cowpeas and groundnuts to Biofix legume inoculants. Seeds were inoculated at the recommended or double the recommended rate at planting. Plants were grown under greenhouse conditions in a Completely Randomized Design for 7 weeks. Control, non-inoculated seeds were also planted and plants grown under the same conditions. At 7 weeks, nodule number and fresh weight per plant, nodule effectiveness (pinkness/redness), and above ground biomass were determined. Biologically fixed nitrogen was determined using the Nitrogen Difference Method. Nodule number and fresh weight per plant were higher at the recommended rate of Biofix application for soya beans and at both rates for groundnuts, while there was no effect on nodule fresh weight at either rate in cowpeas. All representative nodules assessed were effective. There was no significant benefit in inoculating seeds of the three legumes with Biofix on above ground biomass and biological nitrogen fixation. These results could suggest that possibly, the introduced strains though with a stronger nodulation competitiveness, were not as effective at fixing nitrogen as the indigenous strains in the soils in which soya beans, cowpeas and groundnuts have been repeatedly grown before. This could be an indication that sufficient and appropriate effective strains are already present in this soil. In general, the results suggest that to obtain the full benefits of biological nitrogen fixation, legume growers need to be provided with the correct inoculant, where required. Further work under field conditions is recommended to confirm these findings.</p>

Interactions between ecological and socio-economic drivers of Buruli ulcer burden in Sub-Saharan Africa: opportunities for an improved control

2018 ◽  
Author(s):  
Andes Garchitorena ◽  
Matthew H. Bonds ◽  
Jean-Francois Guégan ◽  
Benjamin Roche
Keyword(s):  
Socioeconomic Factors ◽  
Disease Transmission ◽  
Access To Health Care ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Sub Saharan Africa ◽  
Aquatic Environments ◽  
Human Populations ◽  
Complex Interactions ◽  
Sub Saharan

This chapter provides an overview of the complex interactions between ecological and socioeconomic factors for the development and control of Buruli ulcer in Sub-Saharan Africa. We review key ecological and evolutionary processes driving the environmental persistence and proliferation of Mycobacterium ulcerans, the causative agent, within aquatic environments, as well as transmission processes from these aquatic environments to human populations. We also outline key socioeconomic factors driving the economic and health burden of Buruli ulcer in endemic regions, revealed by reciprocal feedbacks between poverty, disease transmission from exposure aquatic environments and disease progression to severe stages owing to low access to health care. The implications of such insights for disease control, both in terms of limitations of current strategies and directions for the future, are discussed.

scholarly journals Functional analysis of multiple nifB genes of Paenibacillus strains in synthesis of Mo-, Fe- and V-nitrogenases

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qin Li ◽  
Haowei Zhang ◽  
Liqun Zhang ◽  
Sanfeng Chen
Keyword(s):  
Functional Analysis ◽  
Nitrogen Fixation ◽  
Gene Cluster ◽  
Biological Nitrogen Fixation ◽  
Deletion Analysis ◽  
Phylogeny Analysis ◽  
Biological Nitrogen

Abstract Background Biological nitrogen fixation is catalyzed by Mo-, V- and Fe-nitrogenases that are encoded by nif, vnf and anf genes, respectively. NifB is the key protein in synthesis of the cofactors of all nitrogenases. Most diazotrophic Paenibacillus strains have only one nifB gene located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV). But some Paenibacillus strains have multiple nifB genes and their functions are not known. Results A total of 138 nifB genes are found in the 116 diazotrophic Paenibacillus strains. Phylogeny analysis shows that these nifB genes fall into 4 classes: nifBI class including the genes (named as nifB1 genes) that are the first gene within the compact nif gene cluster, nifBII class including the genes (named as nifB2 genes) that are adjacent to anf or vnf genes, nifBIII class whose members are designated as nifB3 genes and nifBIV class whose members are named as nifB4 genes are scattered on genomes. Functional analysis by complementation of the ∆nifB mutant of P. polymyxa which has only one nifB gene has shown that both nifB1 and nifB2 are active in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Deletion analysis also has revealed that nifB1 of Paenibacillus sabinae T27 is involved in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Complementation of the P. polymyxa ∆nifBHDK mutant with the four reconstituted operons: nifB1anfHDGK, nifB2anfHDGK, nifB1vnfHDGK and nifB2vnfHDGK, has shown both that nifB1 and nifB2 were able to support synthesis of Fe- or V-nitrogenases. Transcriptional results obtained in the original Paenibacillus strains are consistent with the complementation results. Conclusions The multiple nifB genes of the diazotrophic Paenibacillus strains are divided into 4 classes. The nifB1 located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV) and the nifB2 genes being adjacent to nif or anf or vnf genes are active in synthesis of Mo-, Fe and V-nitrogenases, but nifB3 and nifB4 are not. The reconstituted anf system comprising 8 genes (nifBanfHDGK and nifXhesAnifV) and vnf system comprising 10 genes (nifBvnfHDGKEN and nifXhesAnifV) support synthesis of Fe-nitrogenase and V-nitrogenase in Paenibacillus background, respectively.

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