Abstract

CLAVIJO, Claudia et al. Isolation, characterization and identification of diazotrophic bacteria in the rhizosphere of Olea europea "olive" crop in Tacna Peru. Ecol. apl. [online]. 2012, vol.11, n.2, pp.89-102. ISSN 1726-2216.

104 bacteria strains native diazotrophic strain from the rhizosphere of olive in Fundo San Martín de Porres in Tacna-Peru. Correlations were found between bacterial populations with organic material, phosphorous, soils pH, kind of irrigation and root deep. The bacteria were characterized based on their ability growth promoter by production of indole acetic acid (IAA), phosphate solubilization, alfalfa seed germination and growth in Mineral Medium without Nitrogen. 58.65% of strains produced IAA, 25.96% solubilized tricalcium phosphate, 45.2% significantly increased the germination of alfalfa seeds with respect control and maximum growth was 6 x 108 CFU.ml-1 in the growth trial in Mineral Medium without Nitrogen. Subsequently top 20 strains were selected, where strain 11A had the best weighting analyzed (69.02%) over the four variables analyzed. Also, the best results were to: 11A strain (IAA 46.47 µg/ml); 14A strain (5.84 cm2 area of tricalcium phosphate solubilization); 3A strain (45.83% of germination percentage). Molecular analysis of 16S rRNA gene allowed to identify the species: Novosphingobium scionense, Novophingobium resinovorum, Klebsiella pneumoniae subsp. rhinoscleromatis, Erwinia tasmaniensis, Raoultella planticola, Azotobacter vinelandii, Burkholderia metallica and Rhizobium massiliae. Results suggest that these bacteria can be used in greenhouse essays and then at the field as possibly plant growth promoter.

Keywords : diazotrophs; plant growth promoters indole acetic acid (IAA); phosphate solubilization.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )