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Descripción
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| Nitrogen fixing bacteria from Rhizobium genus establish symbiotic associations with legume plants. Within the legume group, common beans (Phaseolus vulgaris L) show the lowest nitrogen fixation efficiency with their corresponding Rhizobium nodulating species. For this reason, selection of Rhizobium strains with high nitrogen fixing efficiency is a realistic strategy to improve benefits associated to this symbiotic interaction. In order to describe Rhizobium biodiversity in Chilean soils, we performed a molecular characterization of 256 natural isolates from nodules of bean plants grown in soils of the central-south region of Chile. The molecular characterization was performed by analyzing the RFLP/HinfI polymorphism of the nodC gene coding region (950 bp). For this assay we used Rhizobium tropici CIAT899, Rhizobium etli UPM8026, and Rhizobium leguminosarum bv phaseoli H132 as control strains. RFLP patterns obtained were grouped using a similarity analysis with the Jaccard index. This analysis was completed by sequencing an internal fragment of the 16S rRNA gene (320 bp) from isolates that showed differences in their nodC gene RFLP patterns. Sequences obtained were aligned with ClustalW software, and a dendrogram was constructed using a neighbor joining algorithm. The RFLP analysis showed nine different patterns. The predominant pattern (G) was present in 32% of isolates and was very similar to that of R. etli and R. leguminosarum bv phaseoli; similar results were obtained in the 16S rRNA analysis of isolates showing the G pattern. The second most predominant RFLP pattern was type B (25% of isolates) that was closely related to that of R. tropici. This result was also supported by the 16S rRNA sequence analysis. Finally, type A isolates (20%) were grouped with R. etli in both analyses. This is the first report of R. tropici and R. etli strains nodulating bean plants in Chilean soils. | |
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Internacional
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Nombre congreso
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23ª Reunión Latinoamericana de Rhizobiología y I Workshop sobre Perspectivas de las Biofertilizaciones en Iberoamérica. |
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Tipo de participación
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960 |
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Lugar del congreso
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La Falda, Argentina |
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Revisores
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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25/03/2007 |
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Fecha fin congreso
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29/03/2007 |
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