Fifty-eight new isolates were obtained from root nodules of common bean (Phaseolus vulgaris) cultivated in soils originating from different agroecological areas in Senegal and Gambia (West Africa). A polyphasic approach including both phenotypic and genotypic techniques was used to study the diversity of the 58 Rhizobium isolates and to determine their taxonomic relationships with reference str...

The ability of rhizobacteria to compete with other microorganisms for root colonization may be critical for its establishment on a root. Over a 6 day period, visualization of the spatial and temporal rhizosphere distribution of a bioluminescent-marked rhizobacterium, Pseudomonas putida, strain GR7.4lux, was examined on soybean grown in non-sterile soil conditions. Luminometry technologies showe...

Quantification of acidity tolerance in the laboratory may be the first step in rhizobial strain selection for the Amazon region. The present method evaluated rhizobia in Petri dishes with YMA medium at pH 6.5 (control) and 4.5, using scores of 1.0 (sensitive, “no visible” growth) to 4.0 (tolerant, maximum growth). Growth evaluations were done at 6, 9, 12, 15 and 18 day periods. This method perm...

Multilocus sequence typing (MLST), a sequence-based method to characterize bacterial genomes, was used to examine the genetic structure in a large collection of Medicago-nodulating rhizobial strains. This is the first study where MLST has been applied in conjunction with eBURST analysis to determine the population genetic structure of nonpathogenic bacteria recovered from the soil environment. ...

The cultivation of grain legumes (e.g., common bean) in sub-Saharan Africa contributes to the provision food for a growing population and delivers environmental benefits such as inputs nitrogen (N) crops soil via symbiotic fixation (SNF). However, success SNF is constrained by several factors poor efficiency native rhizobial strains fix N, low availability phosphorus (P) acidity soils. Two tria...

AIMS To determine the biodiversity of rhizobial strains nodulating Cicer arietinum L. in representative soils from various areas of Morocco. METHODS AND RESULTS Symbiotic traits, utilization of 49 carbohydrate sources, resistance to antibiotics and heavy metals, tolerance to salinity, to extreme temperatures and pH were studied as phenotypic markers. In addition, restriction fragment length p...

The chemical compounds contained in leguminous plant root exudation induce structural and compositional transitions of the lipopolysaccharides of Rhizobium that occur during rhizobia-legume symbiotic infection processes. The root exudate was extracted from the seed germinated solution and seedling roots of soybean. We added the exudation to bacteria cultured medium. Rhizobium and Bradyrhizobium...

This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied....