Efecto de la aplicación de bacterias productoras de sustancias humicas mediante la biosolubilización de carbón de bajo rango en un suelo salino-sódico en el Valle del Cesar

La salinidad es un problema de degradación que es común en los suelos del Valle del Cesar y el departamento de la Guajira debido a la susceptibilidad que presentan por la presencia de sales y sodio elevados lo que afecta la productividad de los cultivos. Como alternativa para el manejo de la salinidad de los suelos se ha utilizado la aplicación de enmiendas orgánicas que permitan generar cambios favorables en las propiedades del suelo. Por tanto, el objetivo de esta investigación fue evaluar el efecto del carbón de bajo rango (CBR) y las bacterias solubilizadoras de carbón (BSC) Bacillus mycoides, Microbacterium sp y Acinetobacter baumannii sobre algunas propiedades químicas, biológicas y físicas de un suelo Salidic Calciustolls en el Valle del Cesar. Para ello se realizaron dos experimentos: uno en condiciones de invernadero y otro en campo que permitiera observar en un contexto real el efecto del CBR y las BSC. Como variables de respuesta se determinó la respiración del suelo, la actividad microbiológica mediante la hidrólisis del diacetato de fluoresceína (DAF), la actividad de enzimas ligninolíticas relacionadas con la biotransformación del carbón mediada por microorganismos. En complemento, se evaluaron algunas variables químicas asociadas a la salinidad sódica del suelo y la densidad aparente. Se encontró que el tratamiento del suelo con CBR al 1% bajo condiciones de invernadero favorece la actividad biológica, la cual se vio reflejada en el incremento de la respiración del suelo, la actividad de enzimas hidrolíticas sobre el DAF, la actividad de las enzimas lignino peroxidasas (LiP) y lacasas (Lac) asociadas a la biotransformación de CBR; también incrementó la capacidad de intercambio catiónico (CIC) y se registró una disminución en algunos parámetros químicos del suelo. En condiciones de campo la adición de CBR a razón de 5 kg de CBR/m2 contribuyó a disminuir la conductividad eléctrica (C.E.), la razón de absorción de sodio (RAS) y el porcentaje de sodio intercambiable (PSI); no se encontraron cambios significativos sobre el pH y la densidad aparente. En relación a los parámetros de actividad biológica se registraron incrementos en la respiración, la actividad microbiológica y la actividad de la actividad de las enzimas LiP, manganeso peroxidasa (MnP) y Lac; también se observó incrementos en la CIC. Los resultados de los dos experimentos muestran que hay un mayor efecto sobre las propiedades químicas y biológicas del suelo cuando se aplica el CBR en conjunto con las BSC, lo cual sugiere la posibilidad de utilizar y aprovechar el CBR como material orgánico humificado para el manejo de los suelos afectados por salinidad en el área de influencia de la minería del carbón en el Valle del Cesar, con ayuda de la microbiota que como se ha demostrado actúa sobre el CBR liberando la materia orgánica humificada.Abstract. Salinity is a problem of degradation that is common in the soils of the Valley of Cesar and Guajira Department due to susceptibility presented by the presence of salts and high sodium that affects crop productivity. As an alternative for the management of soil salinity has used the application of organic amendments that will generate favorable changes in soil properties. Therefore, the objective of this research was to evaluate the effect of low-rank coal (LRC) and coal-solubilizing bacteria (CSB) Bacillus mycoides, Microbacterium sp and Acinetobacter baumannii on chemical, biological and physical properties of a soil Salidic Calciustolls Valley of Cesar. For this, two experiments were performed: one in the greenhouse and one field that would be observed in a real context the effect of CBR and the BSC. As response variables soil respiration, microbiological activity by hydrolysis of fluorescein diacetate (DAF), ligninolytic activity related enzymes mediated biotransformation microorganisms coal were determined. In complement, some chemical variables associated with sodium soil salinity and bulk density were evaluated. It was found that treating the soil with LRC 1% under greenhouse conditions favors the biological activity, which was reflected in the increase in soil respiration activity of hydrolytic enzymes on the DAF, activity of enzymes lignin peroxidases (LiP) and laccase (Lac) associated with the biotransformation of LRC; also increased cationic exchange capacity (CEC) and a decrease was registered in some chemical soil parameters. Under field conditions the addition of LRC to reason 5 kg LRC/m2 contributed to decrease the electrical conductivity (EC), the sodium absorption ratio (SAR) and exchangeable sodium percentage (ESP); no significant change on the pH and the bulk density were found. In relation to the parameters of biological activity increases in respiration, microbiological activity and LiP enzymes, manganese peroxidase (MnP) and Lac activity were recorded; increases were also observed in the CEC. The results of the two experiments show that there is a greater effect on chemical and biological soil properties when the LRC is applied in conjunction with the CSB, which suggests the possibility to use and exploit the LRC as humified organic material for handling soils affected by salinity in the area of influence of coal mining in the Valle del Cesar, with the help of the microorganism as demonstrated acts on the LRC releasing the humified organic matter. Keywords:Maestrí

Trichoderma harzianum como promotor del crecimiento vegetal del maracuyá (passiflora edulis var. flavicarpa degener)

Se realizó un experimento en condiciones de laboratorio e invernadero, con el propósito de evaluar el efecto de la cepa nativa TCN-014 y la cepa comercial TCC-005 de Trichoderma harzianum sobre la germinación y el crecimiento temprano del maracuyá. Se adecuaron inóculos de 104, 106 y 108 conidias/mL para cada cepa y se aplicaron a semillas de maracuyá; se evaluó el número de semillas germinadas durante 15 días; se calculó el porcentaje de germinación, el índice de velocidad de germinación y el tiempo medio de germinación. Posteriormente las semillas germinadas se llevaron a condiciones de invernadero y transcurridos dos meses se midió la altura de las plántulas, el grosor del tallo, el número de hojas, la longitud de la raíz y el peso seco total. Todos los tratamientos estimularon la germinación de las semillas y el desarrollo de las plántulas; sin embargo la cepa nativa en concentraciones 106 y 108 conidias/mL mostró resultados superiores frente a la cepa comercial. Los resultados sugieren una acción efectiva de T. harzianum como promotor de crecimiento vegetal, mostrando que tiene potencial para la elaboración de un bioproducto útil para el manejo ecológico del cultivo de maracuyá

Efficiency of rhizobia selection in Rio Grande do Sul, Brazil using biological nitrogen fixation in Phaseolus lunatus

The aim of this research was to evaluate the capacity of symbiotic efficiency of native rhizobia from soils of the state of Rio Grande do Sul (RS), Brazil in Phaseolus lunatus L. plants. Soil and nodule samples from predominant legume plants such as Desmodium species were collected in seven locations of the state of RS. For the isolation of the rhizobia from the soil samples, lima bean “olho de cabra preto” variety and “leucena” (Leucena leucocephala) and plants were used as baits. Subsequently, the symbiotic characterization of the isolates was performed by inoculation on lima bean plants in vitro conditions. The selected bacterial isolates were evaluated for biological nitrogen fixation efficiency in a greenhouse experiment, being determined after: shoot dry mass, root dry mass, nodule dry mass, nitrogen (N) accumulated shoot and calculated the N fixation relative efficiency index. Among the 28 rhizobia isolates tested, 11 induced nodule formation in lima bean. The rhizobia Plu03 and Plu14 stimulated a greater increase of plant dry mass, nodule dry mass and nitrogen accumulation in the shoot, reflecting in a higher relative efficiency index. These results suggest that the isolates Plu03 and Plu14 are more efficient in promoting growth of lima bean, which could be recommended for future agronomic efficiency studies

Effect of a low rank coal inoculated with coal solubilizing bacteria for the rehabilitation of a saline-sodic soil in field conditions

The aim of this research was to assessing changes on some chemical, biological and physical properties of a Salidic Calciustolls, in response enhanced by treatment with low rank coal (LRC) and coal solubilizing bacteria (CSB): Bacillus mycoides, Microbacterium sp and Acinetobacter baumannii, that release humified organic matter (HOM) due to biotrasnsformation of this coal. Over field conditions, plots of 5m2 were treated with the addition of LRC at a dose of 5kg/m2 and the inoculum of coal solubilizing bacteria in suspension of 1x108 bacteria.mL-1 at a dose of 100 mL/m2. Soil respiration, microbiological activity, lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac) enzyme activities were determined. The variables associated with saline sodic soils (electrical conductivity – EC, sodium adsorption ratio – SAR and exchangeable sodium percentage – ESP), cation exchange capacity (CEC) and bulk density (BD) also were determined. The LRC application contributed to the decrease of EC, SAR and ESP, but were not observed significant changes in pH. No significant changes were found in the BD; however, treatment was able to increase soil respiration, microbiological activity, and stimulation of LiP, MnP and Lac enzymes activity, as well as an increase in soil CEC. These results suggest the possibility of using the LRC as HOM source for the rehabilitation of degraded saline soils, considering that this kind of involvement is a common problem in soils of the Cesar River Valley in the Colombian Caribbean dry lands influenced by coal mining opencast. Keywords: lignite, humic substances, biotransformation coal, soil salinit

Biological nitrogen fixation by rhizobium sp. native gliricidia (gliricidia sepium [jacq.] kunth ex walp.) under greenhouse conditions

An experiment was conducted under greenhouse conditions in order to evaluate the association and biological nitrogen fixation (BNF), six native strains of Rhizobium sp isolated from nodules gliricidia and a commercial strain (Rhizobiolc). Suspensions of 106 and 108 cells/mL for each of the strains studied and applied in two separate trials: the first with seeds and the second with seedlings 35 days of age gliricidia. In the seed test is calculated the cumulative percentage of germination for 7 days. In both trials after 42 days in seeds and seedlings 52 days in length was measured and stem diameter, leaf number, dry weight of aerial parts, number of nodules/plant and percentage of nitrogen. All treatments stimulated germination, growth and BNF, being better in the native strains at a concentration of 108 cells/mL, compared with the commercial strain and the control. These results indicate the positive effect exerted by Rhizobium sp., in promoting growth and BNF, which could be used for further studies to establish the production of a biofertilizer, allowing potentiate the production of crops by gliricidia for food arich cattle as source of protein in the Caribbean Biotechnology Center

Rizóbios autóctones eficientes na fixação de nitrogênio em Leucaena leucocephalano Rio Grande do Sul, Brasil

La selección de rizobios nativos fijadores de nitrógeno (N) es importante para la producción de leucaena utilizada en la producción pecuaria. En el estado de Rio Grande do Sul (RS), Brasil es escasa la información de cepas nativas de rizobios con capacidad simbiótica con plantas de leucaena. El objetivo de este trabajo fue seleccionar rizobios nativos, eficientes en la fijación biológica de N en plantas de leucaena en RS. Se tomaron muestras de suelo y nódulos en diferentes localidades de RS, luego se utilizaron semillas de leucaena para obtener nódulos que fueron procesados en medios de cultivo para la obtención de los aislamientos. Se realizó un experimento en condiciones de invernade-ro para evaluar la eficiencia de los rizobios, mediante la determinación de la masa seca de la parte aérea (MSPA), masa seca de la raíz, número de nódulos y N acumulado de las plantas. Se seleccionaron los aislamientos de rizobios Leu01 y Leu02 como eficientes en la fijación de N por proporcionar aumento de la MSPA y acumulo de N en las plantas de leucaena similar al tratamiento control que recibió N mineral. Por tanto, estos aislamientos podrían ser promi-sores en futuros estudios en invernadero y campo de esta leguminosa.The selection of native rhizobia nitrogen (N)-fixing is important for the pro-duction of leucaena used in livestock production. In the state of Rio Grande do Sul (RS), Brazil there is little information of native isolates of rhizobia with symbiotic capacity with leucaena plants. The objective of this research was to select native rhizobia, efficient in the biological N fixation in leucaena plants in RS state. Soil and nodule samples were taken at different locations in RS, then leucaena seeds were used to obtain nodules that were processed in culture media to obtain the isolates. An experiment under greenhouse conditions was conducted to evaluate the efficiency of rhizobia isolates. The dry shoot dry mass (SDM), dry mass of the root, number of nodules and the N accumulated N of the plants were determined. The isolates of rhizobia Leu01 and Leu02 were selected as efficient in N fixation because they provide increase in MSPA and an accumulation of N in leucaena plants similar to the control treatment that received N mineral. These isolates could be promising in future greenhou-se and field studies of this legume.A seleção de rizóbios autóctones fixadores de nitrogênio (N) é importante para a produção de leucena utilizada para a produção pecuária. No estado do Rio Grande do Sul (RS), Brasil, existem poucas informações sobre isolados de rizóbios autócto-nes com capacidade simbiótica com plantas de leucena. O objetivo deste trabalho foi selecionar isolados de rizóbios autóctones, eficientes na fixação biológica de ni-trogênio em plantas de leucena no estado do RS. Foram coletadas amostras de solo e nódulos em diferentes locais do RS e, logo foram utilizadas sementes de leucena para obter os nódulos que em seguida foram processados em meios de cultura para obtenção dos isolados. Foi conduzido um experimento em casa de vegetação para avaliar a eficiência dos isolados de rizóbios, determinando-se a massa seca da parte aérea, massa seca da raiz, número de nódulos e nitrogênio acumulado nas plantas. Foram selecionados os isolados de rizóbios Leu01 e Leu02 como eficientes na fixação de N por proporcionarem o aumento da MSPA e acumulo de N nas plantas de leuce-na, semelhante ao tratamento controle não inoculado que recebeu fertilização nitrogenada, sendo estes isolados considerados como promissores que poderiam ser utilizados em outros estudos em casa de vegetação e campo desta leguminosa

Efecto de carbón tipo lignito sobre el crecimiento y producción de pigmentos de Arthrospira platensis

La producción de biomasa y pigmentos a partir de Arthrospira platensis ha cobrado gran importancia, debido a que estos  tienen aplicaciones en producción de alimentos, metabolitos de interés biotecnológico e industrial. No obstante, para la producción de biomasa y pigmentos se han utilizadodiversos sustratos que generan altos costos. Se estudió el crecimiento y producción de pigmentos de A. platensis bajo la influencia de seis concentraciones de carbón de bajo rango (CBR) tipo lignito (10, 20, 30, 40, 50, 60 mg/L) frente a una concentración de AIA (80 mg/L), se realizaron cultivos en batch en medio Zarrouk suplementados con CBR tipo lignito y AIA, bajo condiciones de aireación constante y fotoperiodos de 12:12 horas, durante 33 días. Los valores promedios más altos que se obtuvieron en cuanto a producción de biomasa y pigmentos se lograron en los cultivos suplementados con 50 y 60 mg/L de CBR tipo lignito con respecto a los controles. Los resultados  obtenidos dan constancia al uso potencial del CBR como materia orgánica humificada, rica en nutrientes para el cultivo A. platensis que podrían ser aprovechado en medios acuíferos que son expuestos a la explotación carbonífera, contribuyendo a procesos de depuración y biorremediación de aguas contaminadas con materiales carboníferos.The Biomass production and pigments from Arthrospira platensis has become very important, because these have applications in food production, metabolites of biotechnological and industrial products. However, for the production of biomass and pigments they have been used various substrates that generate high costs. Growth and pigment production A. platensis under the influence of six concentrations of low rank coal (LRC) type lignite (10, 20, 30, 40, 50, 60 mg / L) was tested against a concentration of AIA (80 mg / L), in batch cultures, performed in Zarrouk medium supplemented with LRC type lignite and AIA, under constant aeration and photoperiod of 12:12 hours, for 33 days. The highest average values obtained in terms of biomass production and pigments were achieved in the cultures supplemented with 50 and 60 mg/L of LRC type lignite with respect to the controls. The results provide evidence of the potential use of CBR as humified organic matter, rich in nutrients for growing A. platensis that could be tapped into aquifers means they are exposed to coal mining, contributing to processes of purification and bioremediation of contaminated waters carboniferous materials.Key words: lignite coal type, pigments, solubilization, growth rate

Selección de rizobios eficientes en líneas de frijol común (Phaseolus vulgaris L.) tolerantes a sequía

Common bean (Phaseolus vulgaris L.) yield is limited by prolonged drought conditions and nutrients scarcity in the soil. The Colombian Agricultural Research Corporation (AGROSAVIA) selected five common bean genotypes for presenting biofortification characteristics, good grain size and water deficit tolerance, however, sustainable techniques are required that contribute to the adaptation of these genotypes, and mitigate the impact of drought and nutrient scarcity on the crop production. Plant growth promoting rhizobacteria is an alternative to improve nutrients absorption and plants adaptation to adverse conditions. In this work, the efficiency of rhizobia in biological nitrogen fixation (BNF) in selected common bean genotypes was evaluated. Soil samples were taken in the rhizosphere and roots of the five bean genotypes at the Motilonia Research Center, as well as two alternative samplings in other areas of the Cesar department. Bean seeds were used as a trap to obtain nodules in the laboratory. The nodulation and biological nitrogen fixation of 11 strains from the AGROSAVIA bank in five bean genotypes were evaluated and the symbiotic efficiency of 7 of the strains in four of the genotypes was measured. Three isolates with rhizobia characteristics, symbionts of the 77-SMG22 genotype, were obtained. The most efficient strains in BNF were P17 and P22 in genotype 45-HTA10-2, strains C229 and P37 in 48-HTA14-1, in genotype 56-DAB295 all symbiont strains were efficient (C229, P03, P22 and P37), and in the 77-SMG22 genotype the most efficient treatment was the commercial inoculant Rhizobiol®. Therefore, the strains from the AGROSAVIA bank promote the development of some common bean genotypes reflected in the growth of the plants.El rendimiento de frijol común (Phaseolus vulgaris L.) se ve limitado por condiciones de sequía prolongada y escasez de nutrientes en el suelo. La Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA) seleccionó cinco genotipos de frijol común por presentar características de biofortificación, buen tamaño de grano y tolerancia al déficit hídrico, sin embargo, se requiere técnicas sostenibles que contribuyan a la adaptación de estos genotipos, y mitiguen el impacto de la sequía y escasez de nutrientes en la producción de este cultivo. Las rizobacterias promotoras de crecimiento vegetal son una alternativa para mejorar la absorción de nutrientes y la adaptación de las plantas a condiciones adversas. En este trabajo se evaluó la eficiencia de rizobios en la fijación biológica de nitrógeno (FBN) en los genotipos de frijol común seleccionados. Se tomaron muestras de suelo en la rizósfera y raíces de los cinco genotipos de frijol en el Centro de Investigación Motilonia, como también dos muestreos alternativos en otras zonas del departamento del Cesar. Se utilizaron las semillas de frijol como trampa para obtener nódulos en el laboratorio. También se evaluó la nodulación y la FBN de 11 cepas del banco de AGROSAVIA en los cinco genotipos de frijol y se midió la eficiencia simbiótica de 7 de las cepas en cuatro de los genotipos. Se obtuvieron 3 aislados con características de rizobios, simbiontes del genotipo 77-SMG22. Las cepas más eficientes en la FBN fueron la P17 y P22 en el genotipo 45-HTA10-2, las cepas C229 y P37 en el 48-HTA14-1, en el genotipo 56-DAB295 todas las cepas simbiontes fueron eficientes (C229, P03, P22 Y P37), y en el genotipo 77-SMG22 el tratamiento más eficiente fue el inoculante comercial Rhizobiol®. Por tanto, las cepas del banco de AGROSAVIA promueven el desarrollo de algunos genotipos de frijol común reflejado en el crecimiento de las plantas

Restoration of soil quality using biochar and brown coal waste: A review

Soils in intensively farmed areas of the world are prone to degradation. Amendment of such soils with organic waste materials attempts to restore soil quality. Organic amendments are heterogeneous media, which are a source of soil organic matter (SOM) and maintain or restore chemical, physical, biological and ecological functionality. More specifically, an increase in SOM can influence the soil microclimate, microbial community structure, biomass turnover and mineralisation of nutrients. The search is on-going for locally sourced alternatives as many forms may be costly or geographically limiting. The present review focuses on a heterogeneous group of amendments i.e. biochar and brown coal waste (BCW). Both biochar (made from a variety of feedstocks at various temperatures) and BCW (mined extensively) are options that have worldwide applicability. These materials have very high C contents and soil stability, therefore can be used for long-term C sequestration to abate greenhouse gas emissions and as conditioners to improve soil quality. However, biochar is costly for large-scale applications and BCW may have inherently high moisture and pollutant contents. Future studies should focus on the long-term application of these amendments and determine the physicochemical properties of the soil, bioavailability of soil contaminants, diversity of soil communities and productivity of selected crops. Furthermore, the development of in situ technologies to lower production and processing costs of biochar and BCW would improve their economic feasibility for large-scale application

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field