ABSTRACT
Aims: The aim of this study was to characterize phenotypically and genotypically bacterial isolated from the soils of the Errachidia province in order to select the ones having the potential to solubilize the inorganic phosphate. Study Design: Rhizosphere soil samples for different legumes in sixteen sites from Errachidia province were collected for the assessment. Place and Duration of Study: Department of Biology (Soil & Environment Microbiology Unit) Faculty of Sciences, Moulay Ismail University and Technical Support Unit for Scientific Research, CNRST in Rabat; between September 2012 and January 2013. Methodology: The samples were collected from 16 different sites belonging to Errachidia province in order to select bacterial strains able to solubilize inorganic phosphate. Morphological, cultural and phenotypic parameters of the isolated strains were evaluated. Phenotypic characteristics include the use of carbohydrates, tolerance to temperature, salt and pH. The genotypic diversity between the selected isolates was investigated throught 16S rDNA gene sequencing. Results: 19,4% from the 62strains isolated were selected as PSBs; They showed phenotypic heterogeneity confirmed by the genetic one. Their effectiveness on the solid growth medium was greater which was confirmed by the significant index of solubilization of each strain. Although that on the broth medium the concentration of the solubilized phosphorus differs from one strain to another, a negative correlation moderately strong between the final pH of the growth medium and the concentration of the solubilized phosphorus was deduced. Also a lack of correlation between the index of solubilization and concentration was concluded (r = -0.08). Conclusion: The importance of the phosphorus soluble forms for the agricultural production and taking in consideration the environmental concerns and sustainable developments compromise the use of cheapest and natural techniques to protect the environment.
ABSTRACT
Aims: The objectives were to isolate and characterize phenotypically and genotypically the rhizobial strains from the soils belonging to the Meknes-Tafilalet region in order to select strains that are able to nodulate Bituminaria bituminosa. Study Design: An experimental study. Place and Duration of Study: Department of biology (Soil & Environment Microbiology Unit) Faculty of Sciences, Moulay Ismail University and Technical Support Unit for Scientific Research, CNRST in Rabat; between January and August 2010. Methodology: Samples from 23 different sites belonging to the Meknes-Tafilalet region were collected in order to select rhizobial strains that are able to nodulate Bituminaria bituminosa. The morphological, cultural and phenotypic parameters of isolated strains were studied. The phenotypic characteristics include colony morphology, growth speed, tolerances to temperature, salt and pH. To assess the genotypic diversity among the isolates, molecular characteristics based on 16S rDNA gene sequencing were performed. Results: The majority of the isolated strains showed fast-growing capacity (75%). Most strains tolerate neutral to alkaline pH, however some strains (18%) showed weak growth capacity at pH 4. All isolates were tolerant to high salt stress ([NaCl] = 3%). The genotypic characterization based on16S rDNA gene sequencing of the twelve strains showed a high diversity between the isolates. Conclusion: Taken together, our results highlight the important biodiversity of the isolated rhizobial strains and open opportunities for the development of new bio-fertilizer.