Laura tortora - Academia.edu (original) (raw)

Papers by Laura tortora

Las bacterias del género Azospirillum producen efectos benefciosos en el crecimiento de las plant... more Las bacterias del género Azospirillum producen efectos benefciosos en el crecimiento de las plantas y el rendimiento de los cultivos, debido a su capacidad de fijar el nitrógeno atmosférico y de producir sustancias estimuladoras del crecimiento. En Cuba, se utiliza de manera satisfactoria en la biofertilización de la caña de azúcar y otros cultivos económicos la cepa 8-INICA de Azospirillum sp. Su caracterización morfológica y bioquímica, indicó similitud conla especie A. brasilense. Por la importancia de esta cepa en la continuidad de las labores de biofertilización que se ejecutan en el país, el objetivo del trabajo fue corroborar la identidad de la misma mediante el empleo de técnicas inmunológicas y moleculares.Azospirillum is a bacterium that produces growth and yields increments due to its capacity of fix atmospheric nitrogen and to produce phytohormones. In Cuba, the 8-INICA strain of Azospirillum sp. has been used successfully in sugarcane biofertilization and others economi...

Plant and Soil, 2007

Azospirillum species are free-living nitrogen-fixing bacteria commonly found in soil and in assoc... more Azospirillum species are free-living nitrogen-fixing bacteria commonly found in soil and in association with roots of different plant species. For their capacity to stimulate growth they are known as plant growth-promoting bacteria (PGPB). In this work, we demonstrate the natural occurrence and colonization of different parts of strawberry plants by Azospirillum brasilense in the cropping area of Tucumán, Argentina. Although bacteria isolations were carried out from two strawberry cultivars, e.g., Camarosa and Pájaro, attempts were successful only with the cultivar Camarosa. Whereas different strains of Azospirillum were isolated from the root surface and inner tissues of roots and stolons of the cultivar Camarosa, we have not obtained Azospirillum isolates from the cultivar Pájaro. After microbiological and molecular characterization (ARDRA) we determined that the isolates belonged to the species A. brasilense. All isolates showed to have the capacity to fix nitrogen, to produce siderophores and indoles. Local isolates exhibited different yields of indoles production when growing in N-free NFb semisolid media supplemented or not with tryptophan (0.1 mg ml À1). This is the first report on the natural occurrence of A. brasilense in strawberry plants, especially colonizing inner tissues of stolons, as well as roots. The local isolates showed three important characteristics within the PGPB group: N 2-fixation, siderophores, and indoles production.

DOAJ: Directory of Open Access Journals - DOAJ, Jun 1, 2020

RESUMEN Efecto del residuo agrícola de la cosecha en verde de la caña de azúcar en el desarrollo ... more RESUMEN Efecto del residuo agrícola de la cosecha en verde de la caña de azúcar en el desarrollo de microorganismos de importancia agrícola y ambiental En la actualidad, la industria azucarera mundial tiende a reemplazar la quema del cañaveral previo a la cosecha, por el sistema de caña verde. Trabajos demuestran que cuando el residuo agrícola de cosecha (RAC) regresa al suelo, aporta nutrientes, materia orgánica y mejora su estructura. Sin embargo, el efecto del RAC en el desarrollo de microorganismos del suelo aún no ha sido evaluado en Tucumán, R. Argentina. Por esta razón, el objetivo de este trabajo fue evaluar los cambios que ocurren en el desarrollo de microorganismos de importancia agrícola y ambiental, en dos situaciones de manejo del suelo: con y sin mantenimiento de cobertura con RAC. Los ensayos se realizaron en el Dpto. Leales, Tucumán, utilizando la variedad LCP 85-384 en la edad de soca 4; es decir, los tratamientos se establecieron cuatro años antes del muestreo. Para el análisis microbiológico, se tomaron muestras de suelo y de diferentes tejidos durante los meses de junio, julio, noviembre 2011 y mayo 2012. El recuento de microorganismos se realizó utilizando diferentes medios de cultivo: LB para aerobios mesófilos totales, APG para hongos y levaduras, AC para Pseudomonas sp. y medios de cultivo semisólidos libres de N2 para bacterias microaeróbicas fijadoras de nitrógeno. En forma general, se observó que la cobertura con RAC aumentó el número de hongos, levaduras y Pseudomonas sp. durante las épocas con temperaturas más altas. Algunos hongos presentaron actividad ligninolítica y algunas Pseudomonas sp. fueron capaces de solubilizar fósforo, lo que indica que estos microorganismos podrían estar involucrados en la descomposición del residuo. Fue interesante observar que la cobertura con RAC también incrementó el número de bacterias fijadoras de nitrógeno asociadas a raíces y tallos, de junio a febrero. El mayor desarrollo de microorganismos degradadores de materia orgánica y una mejor colonización de los tejidos por bacterias fijadoras de nitrógeno podrían mejorar el crecimiento y desarrollo del cañaveral.

World Journal of Microbiology and Biotechnology, 2009

Azospirillum brasilense (strains REC3, RLC1, PEC5) were root inoculated in strawberry plants of t... more Azospirillum brasilense (strains REC3, RLC1, PEC5) were root inoculated in strawberry plants of the cultivars 'Milsei', 'Selva' and 'Camarosa' to assess plant growth-promoting effects. The bacteria were able to promote plant growth (expressed as root length, root area, and dry weight of root and shoot), depending on the genotypes of plants and bacteria used, whereas the stolon production (3-4) depended only on the strawberry cultivar. To explain whether root exudates plays any role on the growth-promotion observed herein, total protein and sugar were determined, and chemotaxis properties were evaluated. The strains showed positive chemotaxis toward the root exudates, being influenced by the total sugars content, suggesting that the latter plays an important role in the chemotaxis effect and may contribute to enhance the root capacity to recruit azospirilla from rhizosphere, thus improving the growth-promoting effect exerted by these bacteria.

Revista Argentina de Microbiología

et al., The drop plate method as an alternative for Azospirillum spp viable cell enumeration with... more et al., The drop plate method as an alternative for Azospirillum spp viable cell enumeration within the consensus protocol of the REDCAI network,

Estación Experimental Agroindustrial Obispo Colombres, Mar 1, 2017

Revista Agronómica del Noroeste Argentino, 2017

Revista Industrial y Agrícola de Tucumán, Dec 20, 2017

Revista Industrial y Agrícola de Tucumán, Apr 25, 2018

Sugarcane is one of the most relevant bioenergy crops in Argentina. Due to its high capacity for ... more Sugarcane is one of the most relevant bioenergy crops in Argentina. Due to its high capacity for biomass production, the crop has a high nitrogen requirement that can be supplied using chemical fertilizers. To ensure the sustainability of bioenergy programs and reduce the environmental issues caused by synthetic fertilizers, it is necessary to replace them in a short term. In this sense, Azospirillum inoculation constitutes the most used alternatives in our region to increase sugarcane plantations yields. The objective of this work was to isolate and characterize Azospirillum bacteria from sugarcane, analyze some of their PGPB characteristics and evaluate the effect of bioproducts formulated with the obtained isolates on crop sprouting. Three endophytic isolates (Ls1, Ls2 and Ls3) and two from the rhizosphere (Tv1 and Tv2) were obtained, with potential ability to fix atmospheric nitrogen and produce total indoles. Using 16S gene restriction and sequencing, the isolates were identifi...

$Research paper thumbnail of {"__content__"=>"The Endophytic Strain Kd70 Lacks Pathogenic Island-Like Regions in Its Genome and Is Incapable of Infecting the Urinary Tract in Mice.", "i"=>{"__content__"=>"Klebsiella michiganensis"}}$

Frontiers in microbiology, 2018

spp. have been isolated from many different environmental habitats but have mainly been associate... more spp. have been isolated from many different environmental habitats but have mainly been associated with nosocomial acquired diseases in humans. Although there are many recently published sequenced genomes of members of this genus, there are very few studies on whole genome comparisons between clinical and non-clinical isolates, and it is therefore still an open question if a strain found in nature is capable of infecting humans/animals. Kd70 was isolated from the intestine of larvae of but genome analysis revealed multiple genes associated with colonization and growth promotion in plants suggesting an endophytic lifestyle. Kd70 cells labeled with confirmed capability of root colonization and soil application of Kd70 promoted growth in greenhouse grown sugarcane. Further genomic analysis showed that the Kd70 genome harbored fewer mammalian virulence factors and no pathogen island-like regions when compared to clinical isolates of this species, suggesting attenuated animal/human patho...

evaluate the dynamics of sugarcane residue decomposition and to study nutrient release from resid... more evaluate the dynamics of sugarcane residue decomposition and to study nutrient release from residue. The trial was conducted in Tucumán-Argentina from 2008 to 2012. The sugarcane cultivars used were LCP 85-384 and RA 87-3. Every 25–35 days we evaluated: 1) residue fresh and dry weight and 2) residue C/N ratios. At the beginning and end of each cycle, we evaluated residue P and K content. LCP 85-384 initial residue amounts ranged from 11.6 t/ha to 15.2 t/ha, whereas decomposition rates were between 43% and 59%. RA-87-3 initial residue amounts ranged from 12.5 t/ha to 18.1 t/ha, with decomposition rates between 36% and 60%. Fresh residue C/N ratios were over 60. The highest initial C/N ratios were 79.2 (in 2008/09) and 102.9 (in 2009/10) for LCP 85-384 and RA 87-3, respectively. At the end of each crop cycle, trash C/N ratios dropped significantly. Residue initial C concentration was between 42%–45.5% and 38.8%–47.5% for LCP 85-384 and RA 87- 3, respectively. Residue initial N concent...

Archives of Microbiology, 2011

Anthracnose, caused by the fungus Colletotrichum acutatum is one of the most important diseases i... more Anthracnose, caused by the fungus Colletotrichum acutatum is one of the most important diseases in strawberry crop. Due to environmental pollution and resistance produced by chemical fungicides, nowadays biological control is considered a good alternative for crop protection. Among biocontrol agents, there are plant growth-promoting bacteria, such as members of the genus Azospirillum. In this work, we demonstrate that under iron limiting conditions different strains of A. brasilense produce siderophores, exhibiting different yields and rates of production according to their origin. Chemical assays revealed that strains REC2 and REC3 secrete catechol type siderophores, including salicylic acid, detected by thin layer chromatography coupled with fluorescence spectroscopy and gas chromatography-mass spectrometry analysis. Siderophores produced by them showed in vitro antifungal activity against C. acutatum M11. Furthermore, this latter coincided with results obtained from phytopathological tests performed in planta, where a reduction of anthracnose symptoms on strawberry plants previously inoculated with A. brasilense was observed. These outcomes suggest that some strains of A. brasilense could act as biocontrol agent preventing anthracnose disease in strawberry.