Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production
The genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, iden...
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| Language: | English |
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Wiley
2013-01-01
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| Series: | The Scientific World Journal |
| Online Access: | http://dx.doi.org/10.1155/2013/519603 |
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| author | Esteban Julián Rubio Marcela Susana Montecchia Micaela Tosi Fabricio Darío Cassán Alejandro Perticari Olga Susana Correa |
| author_facet | Esteban Julián Rubio Marcela Susana Montecchia Micaela Tosi Fabricio Darío Cassán Alejandro Perticari Olga Susana Correa |
| author_sort | Esteban Julián Rubio |
| collection | DOAJ |
| description | The genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified as A. chroococcum, A. salinestris, and A. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3) and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2–18.2 μg IAA mL−1, 0.3–0.7 μg GA3 mL−1, and 0.5–1.2 μg Z mL−1. Seed inoculations with further selected Azotobacter strains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solutions, but it was not related to bacterial root colonization. Our survey constitutes a first approach to the knowledge of Azotobacter species inhabiting Argentinean soils in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection of Azotobacter strains for biofertilizer formulations. |
| format | Article |
| id | doaj-art-24c72a9b4a5e426bb1efedc12d82859d |
| institution | Kabale University |
| issn | 1537-744X |
| language | English |
| publishDate | 2013-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | The Scientific World Journal |
| spelling | doaj-art-24c72a9b4a5e426bb1efedc12d82859d2025-02-03T05:44:50ZengWileyThe Scientific World Journal1537-744X2013-01-01201310.1155/2013/519603519603Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer ProductionEsteban Julián Rubio0Marcela Susana Montecchia1Micaela Tosi2Fabricio Darío Cassán3Alejandro Perticari4Olga Susana Correa5Instituto de Microbiología y Zoología Agrícola (IMYZA), Instituto Nacional de Tecnología Agropecuaria (INTA), Dr. Nicolás Repetto y De los Reseros s/n, 1686 Hurlingham, Buenos Aires, ArgentinaCátedra de Microbiología Agrícola/INBA (CONICET/UBA), Facultad de Agronomía, Universidad de Buenos Aires, Av San Martín 4453, C1417DSE Ciudad Autónoma de Buenos Aires, ArgentinaCátedra de Microbiología Agrícola/INBA (CONICET/UBA), Facultad de Agronomía, Universidad de Buenos Aires, Av San Martín 4453, C1417DSE Ciudad Autónoma de Buenos Aires, ArgentinaLaboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 8, Km 601, 5800 Río Cuarto, Córdoba, ArgentinaInstituto de Microbiología y Zoología Agrícola (IMYZA), Instituto Nacional de Tecnología Agropecuaria (INTA), Dr. Nicolás Repetto y De los Reseros s/n, 1686 Hurlingham, Buenos Aires, ArgentinaCátedra de Microbiología Agrícola/INBA (CONICET/UBA), Facultad de Agronomía, Universidad de Buenos Aires, Av San Martín 4453, C1417DSE Ciudad Autónoma de Buenos Aires, ArgentinaThe genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified as A. chroococcum, A. salinestris, and A. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3) and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2–18.2 μg IAA mL−1, 0.3–0.7 μg GA3 mL−1, and 0.5–1.2 μg Z mL−1. Seed inoculations with further selected Azotobacter strains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solutions, but it was not related to bacterial root colonization. Our survey constitutes a first approach to the knowledge of Azotobacter species inhabiting Argentinean soils in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection of Azotobacter strains for biofertilizer formulations.http://dx.doi.org/10.1155/2013/519603 |
| spellingShingle | Esteban Julián Rubio Marcela Susana Montecchia Micaela Tosi Fabricio Darío Cassán Alejandro Perticari Olga Susana Correa Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production The Scientific World Journal |
| title | Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production |
| title_full | Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production |
| title_fullStr | Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production |
| title_full_unstemmed | Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production |
| title_short | Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production |
| title_sort | genotypic characterization of azotobacteria isolated from argentinean soils and plant growth promoting traits of selected strains with prospects for biofertilizer production |
| url | http://dx.doi.org/10.1155/2013/519603 |
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