Bibliographic citations
Chumpitaz, C., (2015). Caracterización de la diversidad de bacterias fijadoras de nitrógeno con capacidad promotora de crecimiento vegetal asociada a una Brassicaceae altoandina, Lepidium meyenii Walp. [Tesis, Universidad Nacional Agraria La Molina]. https://hdl.handle.net/20.500.12996/2695
Chumpitaz, C., Caracterización de la diversidad de bacterias fijadoras de nitrógeno con capacidad promotora de crecimiento vegetal asociada a una Brassicaceae altoandina, Lepidium meyenii Walp. [Tesis]. PE: Universidad Nacional Agraria La Molina; 2015. https://hdl.handle.net/20.500.12996/2695
@misc{renati/2048261,
title = "Caracterización de la diversidad de bacterias fijadoras de nitrógeno con capacidad promotora de crecimiento vegetal asociada a una Brassicaceae altoandina, Lepidium meyenii Walp.",
author = "Chumpitaz Segovia, Carolina Alhelí",
publisher = "Universidad Nacional Agraria La Molina",
year = "2015"
}
Lepidium meyenii W. is the only Brassicaceae that grows in the highlands of Peru. Its root has high value in international markets, due to its nutritional properties. However, this crop needs nutrients to grow, impoverishing the soil after two harvest campaigns; which makes it unsustainable. Diazotrophic bacteria inoculums seems to be a friendly alternative way to improve plant growth and maintain the soil fertility. Therefore, this study was focused in the molecular and phenotypic characterization of the diazotrophs PGPR diversity that belongs to the strain bank of the Laboratorio de Ecologia Microbiana y Biotecnologia Marino Tabusso, Department of Biology, in Universidad Nacional Agraria La Molina. Bacterias were isolated from a maca field located in La Meseta del Bombom, San Pedro de Cajas province - Junin. Forty-seven strains were able to grow on nitrogen free culture medium and all of them were classified into five morphotypes. The majority of the isolates showed big and mucous colonies with the ability to acidify the culture medium. 95.7% of the strains were psicrotrophyles and all of them were neutrophilic with a wide range of pH tolerance between 3 to 9. All bacteria produced indolacetic acid, ranging from values between 0.1 to 75 ug/ml. 74.5% of the isolates were able to solubilize phosphate salts. BOX-PCR fingerprint pattern was done, resulting in 19 different profiles that were identified using 16S rRNA analysis. According to this analysis, it was obtained that bacterias were related to γ-proteobacteria (Pseudomonas, Pantoea, Rahnella, Stenotrophomonas, Serratia and Erwingella), β-proteobacteria (Burkholderia, Achromobacter class and Variovorax); and α-proteobacteria (Rhizobium). Presence of nifH gene was detected in six BOX-PCR clusters. Species related with Rahnella aqualitis, Pseudomonas brenneri, Stenotrophomonas panacihumi, Burkholderia caledonica, Pantoea agglomerans and Serratia liquefaciens, showed the nifH gene, indicating their potential as PGPR with nitrogenase activity (nifH+). Finally, nifH+ PGPR strains were tested in its capability of improve germination of maca seeds, showing a significant (p <0.05) increase in the germination percentage and in dry weight suggesting the relevance of these bacteria for been used as inoculums in this crop.
Tesis en proceso de presentación de artículo científico. Embargo solicitado por el autor el 3 de agosto 2019.
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