Influencia de factores edafo/climáticos sobre poblaciones microbianas de suelos áridos con agricultura bajo riego

El objetivo de este trabajo exploratorio fue evaluar el efecto de las prácticas agrícolas a largo plazo (30 años) sobre la actividad y los aspectos estructurales de la comunidad microbiana de los suelos áridos con agricultura bajo riego. Para ello, se evaluaron tres ambientes, recolectando muestras de un suelo árido Prístino (sin riego y sin disturbar) y dos suelos agrícolas bajo riego con diferente historial de manejo (Alfalfa y Maíz) a lo largo de la temporada 2014-2015. Se realizó un análisis fisicoquímico de los suelos, se registró la temperatura y humedad, así como la actividad biológica total (hidrólisis FDA) y la huella molecular (DGGE y T-RFLP) para cada tratamiento.The agricultural frontier over the arid marginal zones is steadily expanding by means of irrigation technology. Considering the impact of bacterial population and its biological activity on soil homeostasis, information on soil biodiversity and its biological activity are a significant input to maximize the production with minimal impact on these susceptible environments. The aim of this exploratory work was to assess the effect of long term agricultural practices (30 years) on the activity and structural aspects of the microbial community from arid irrigated agricultural soils. For this, three environments were evaluated, collecting samples of a Pristine arid soil (without irrigation and undisturbed) and two different irrigated agricultural (Alfalfa and Corn) throughout the 2014-2015 season. For this, samples from Pristine (without irrigation) arid soil and (Alfalfa and Corn) were collected along the 2014-2015 season. Soil physicochemical analysis was performed, temperature and humidity were recorded, as well as total biological activity (FDA hydrolysis test) and molecular fingerprinting (DGGE and T-RFLP) for each treatment. Soil physicochemical analysis show that agricultural practice improved the edaphic properties like organic matter level, although the contribution of water in limited quantities (pressurized irrigation) an increase in electrical conductivity. Total biological activity along the seasons showed similar profiles for all scenarios, and the coldest/unirrigated and hottest/irrigated-rainy months showed the lowest and highest activities respectively. Overall, the Pristine condition presented significantly lower biological activity levels along the season. The DGGE fingerprint showed a discrete pattern with low number of bands and, against expected, showed no differences between the three scenarios. Subsequent T-RFLP analysis confirmed that soil bacterial biodiversity was not modified by decades of intensive irrigated agricultural activity.AER INTA Colonia 25 de MayoFil: Masseroni, María Lujan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural Colonia 25 de Mayo; ArgentinaFil: Sartor, Paolo Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural Colonia 25 de Mayo; ArgentinaFil: Perez, María Micaela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Rorig, Marcela Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; ArgentinaFil: Merini, Luciano. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentin

Occurrence of powdery mildew disease in wheat fertilized with increasing silicon doses: a chemometric analysis of antioxidant response

Blumeria graminis (Bgt) is a pathogenic fungus that affects severally wheat plants provoking high losses in wheat production. Biochemical parameters like enzyme activity of catalase, superoxide dismutase, or peroxidases can be used to detect changes of metabolism in response to pathogen infection. We evaluated different biochemical and biometrics parameters to assess the effect of silicon, a widely recognized beneficial nutrient, in wheat infected naturally with Bgt. Integral study and interpretation of results obtained by multivariate analysis is the challenge of present work. Wheat plants growing in hydroponic solution were fertilized with increasing concentration of silicon. Responses of wheat plants to silicon treatments were assessed through the analysis of lipid peroxidation and antioxidant enzymes activity (catalase, ascorbate peroxidase and superoxide dismutase). Furthermore, biometric measures such as Pathogen Index, dry weight of shoot and roots, tiller height, spike length, spike mass, grain number and grain mass production were assessed. Pathogen Index decreased while mass and number of grain, dry weight of shoots were significantly increased, proportionally to silicon concentration increasing in culture media; biochemical parameters were also influenced by the concentration of silicon. Multivariate analysis indicated correspondence between increase of silicon treatments and decrease of antioxidant activities of APX, CAT and SOD. Relationships between the applied doses of silicon and decreasing Bgt expansion in foliar surfaces were also observed. Chemometrics proved to be an optimal tool for integrating data about metabolic status and demonstrate, in present case, that increasing concentration of silicon and the reduction of antioxidant enzyme activity are closely related to decreasing of powdery mildew disease.EEA AnguilFil: Moldes, Carlos Alberto. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Lima Filho, Oscar Fontão de. Empresa Brasileira de Pesquisa Agropecuária Oeste; BrasilFil: Merini, Luciano J. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Laboratorio de Malezas y Herbicidas; ArgentinaFil: Tsai, Siu M. Universidade de Sao Paulo. Centro de Energia Nuclear na Agricultura; BrasilFil: Camiña, José Manuel. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentin

Bioaugmentation with PGP-trace element tolerant bacterial consortia affects Pb uptake by Helianthus annuus grown on trace element polluted military soils

In this study, we sought to compose consortia of plant growth-promoting (PGP) and trace element tolerant bacteria, to improve plant growth and inhibit uptake and translocation of trace elements, eventually allowing the cultivation of profitmaking crops on trace elements polluted soils, reducing the risks of entrance of these elements into the food chain. Sunflower (Helianthus annuus L.) was grown on two polluted military soils (MS1 and MS2) in greenhouse microcosms and inoculated with three different bacterial consortia (C1, C2, C3). Growth and physiological status of the plants were unaffected during the experiment with the inoculation. After 2months, plants were harvested. Consortium C2 and C3 decreased Pb shoot bioaccumulation by respectively 80–85% when plants were grown in the MS1 and even to concentrations below detection limit in plants grown in MS2. Differences in uptake and (sub)cellular localization of Pb and Cd in selected bacterial isolates were investigated in vitro by TEM-EDX. Pb absorption was observed by Bacillus wiedmanni ST29 and Bacillus paramycoides ST9 cultures. While adsorption at the bacterial cell wall was observed by Bacillus paramycoides ST9 and retention in the extracellular matrix by Cellulosimicrobium cellulans ST54.Fil: Saran, Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; Argentina. Hasselt University; BélgicaFil: Imperato, V.. Hasselt University; BélgicaFil: Fernandez, L.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Vannucchi, F.. Scuola Superiore Sant’Anna; ItaliaFil: Steffanie, N. M.. Hasselt University; BélgicaFil: d'Haen, J.. Hasselt University; BélgicaFil: Merini, Luciano Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Vangronsveld, Jaco. Hasselt University; Bélgica. Maria Curie Sklodowska University; PoloniaFil: Thijs, Sofie. Hasselt University; Bélgic

Effect of Lippia alba and Cymbopogon citratus essential oils on biofilms of Streptococcus mutans and cytotoxicity in CHO cells

Background: Caries is a public health problem, given that it prevails in 60 to 90% of the school-age global population. Multiple factors interact in its etiology, among them dental plaque is necessary to have lactic acid producing microorganisms like Streptococcus from he Mutans group. Existing prevention and treatment measures are not totally effective and generate adverse effects, which is why it is necessary to search for complementary strategies for their management. Aim: The study sought to evaluate the eradication capacity of Streptococcus mutans biofilms and the toxicity on eukaryotic cells of Lippia alba and Cymbopogon citratus essential oils. Methodology: Essential oils were extracted from plant material through steam distillation and then its chemical composition was determined. The MBEC-high-throughput (MBEC-HTP) (Innovotech, Edmonton, Alberta, Canada) assay used to determine the eradication concentration of S. mutans ATCC 35668 strain biofilms. Cytotoxicity was evaluated on CHO cells through the MTT cell proliferation assay. Results: The major components in both oils were Geraniol and Citral; in L. alba 18.9% and 15.9%, respectively, and in C. citratus 31.3% and 26.7%. The L. alba essential oils presented eradication activity against S. mutans biofilms of 95.8% in 0.01 mg/dL concentration and C. citratus essential oils showed said eradication activity of 95.4% at 0.1, 0.01 mg/dL concentrations and of 93.1% in the 0.001 mg/dL concentration; none of the concentrations of both essential oils showed toxicity on CHO cells during 24 h. Conclusion: The L. alba and C. citratus essential oils showed eradication activity against S. mutans biofilms and null cytotoxicity, evidencing the need to conduct further studies that can identify their active components and in order to guide a safe use in treating and preventing dental caries.EEA AnguilFil: Tofiño Rivera, Adriana Patricia. Universidad de Santander. Facultad de Salud. Grupo de Investigación Cienciaudes; ColombiaFil: Ortega Cuadros, Mailen. Universidad Popular del Cesar; ColombiaFil: Galvis Pareja, David Andrés. Universidad CES; ColombiaFil: Jimenez Rios, Hedilka. Universidad de Santander. Facultad de Salud. Grupo de Investigación Cienciaudes; ColombiaFil: Merini, Luciano J. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Martínez Pabón, María Cecilia. Universidad de Antioquía. Facultad de Odontología. Laboratorio de Microbiología Bucal. Grupo de Investigación en Patología Oral, Periodoncia y Cirugía Alvéolo-Dentaria; Colombi