Environmental context of endophyte symbioses: Interacting effects of water stress and insect herbivory

Symbiotic associations between grasses and fungal endophytes are generally regarded as mutualistic, yet benefits to host plants may vary with environmental context. Previous studies have emphasized how endophytes influence plant responses to single stressors. In contrast, the outcome of endophyte-grass interactions under simultaneous biotic and abiotic stresses remains poorly explored. We hypothesized that benefits from endophyte symbiosis become most apparent in "complex" environments where hosts experience multiple stresses. We evaluated the performance of endophyte-infected (E+) vs. endophyte-uninfected (E-) Lolium multiflorum plants in a factorial experiment with water supply (control vs. drought) and insect herbivory (with aphids vs. without aphids). Endophyte infection delayed tiller production in well-watered plants, while water stress reduced tillering in E- plants. Endophyte mediation of herbivory tolerance was contingent on water supply. Whereas aphid herbivory was detrimental to E+ plants in well-watered soils, aphids interacted with drought stress in decreasing the reproductive output of E- but not E+ plants. Moreover, endophyte presence decreased aphid densities on drought-stressed plants only. Thus, endophyte symbiosis enhanced host tolerance to overlapping biotic and abiotic stresses, although infected plants failed to outgrow their uninfected counterparts. These results support the view that mutualistic endophyte effects may not arise in low-stress environments. © 2011 by The University of Chicago. All rights reserved.Fil: Miranda, M. Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Cuidado ambiental : manejo integral de residuos urbanos

Fil: Semmartin, María. Universidad de Buenos Aires. Facultad de Agronomía; Argentina.Fil: Omacini, Marina. Universidad de Buenos Aires; Facultad de Agronomía; Argentina.La enorme producción de residuos domésticos en las\ngrandes ciudades conforma una de las preocupaciones\nambientales más importantes de la sociedad actual.\nEn este contexto, la FAUBA creó en 2008 el programa\nManejo Integral de Residuos por el Ambiente (MIRA),\npara promover la conciencia y el cuidado del ambiente,\nla reducción del consumo de ciertos materiales y el\nmanejo racional de los residuos domésticos

Pampean-grassland heterogeneity on the intersection of science, art, and culture

Since prehistoric times, temperate grasslands have provided favorable habitat for human subsistence. Ease of exploitation, however, has caused that temperate grasslands are among the most destroyed terrestrial ecosystems. The region known as the Pampas or Rio de la PlataGrasslands, extending over some 750,000 sq. km in central eastern Argentina, Uruguay and southern Brazil, comprises the largest temperate grassland area in the southern hemisphere. Flat topography, humid temperate climate, grassy natural vegetation, and absence of large native herbivores have conditioned multiple aspects of human life in the region, like patterns of population settlement, techniques for acquisition and transportation of goods, aesthetic preferences, and social structure. In this article, we present some writers inspired by the Pampas, we briefly summarize the main results of scientific research on the drivers of vegetation physiognomy and heterogeneity in the Pampas, based on the invaluable floristic database compiled by Professor Rolando J. C. León, and we sketch one of Professor León´s scientific-historic tours to the Pampas. Finally, we call attention to currently threats to the persistence of Pampean Grassland.Fil: Perelman, S.B.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Tognetti, Pedro Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Batista, William B.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Mutualism effectiveness and vertical transmission of symbiotic fungal endophytes in response to host genetic backround

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Recordando a Silvia Burkart (07/12/1942-17/01/2018)

Tognetti, Pedro Maximiliano. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Omacini, Marina. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Oyarzabal, Mariano. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Striker, Gustavo Gabriel. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.606-60

Arbuscular mycorrhizal fungi are directly and indirectly affected byglyphosate application

Fil: Druille, Magdalena. IFEVA. Faculty of Agronomy. University of Buenos Aires; ArgentinaFil: Omacini, Marina. IFEVA. Faculty of Agronomy. University of Buenos Aires; ArgentinaFil: Golluscio, Rodolfo A.. IFEVA. Faculty of Agronomy. University of Buenos Aires; ArgentinaFil: Cabello, Marta Noemí. Instituto Spegazzini. Faculty of Natural Sciences and Museum. National University of La Plata; Argentin

Glyphosate vulnerability explains changes in root-symbionts propagules viability in Pampean grasslands

Research into the impact of agricultural practices on plant symbionts is essential for understanding the factors that modulate plant community productivity and diversity. Although glyphosate is used worldwide as an herbicide, its effects on root symbionts under natural conditions have not been sufficiently studied. We performed a field experiment to evaluate the influence of glyphosate, used for promoting winter forage production, on the viability of arbuscular mycorrhizal fungi (AMF) and rhizobium propagules and other ecosystem traits in native grasslands. The number of viable propagules was strongly reduced with a single application at the recommended dose. Spore viability reduction was dependent on AMF species. Furthermore, changes in plant community composition and soil salinity were detected, which may eventually influence these symbionts in the future. Considering the low nutrient availability and high root-symbiont dependency of several species with forage value, repeated applications might lead to a loss in the grassland diversity and productivity, decreasing livestock production. Application of sublethal doses of this herbicide could avoid these damages, although success in increasing winter forage production would be less. Our results are relevant for understanding the effects of glyphosate on non-target species and designing sustainable land management systems.Facultad de Ciencias Naturales y Muse

Glyphosate decreases mycorrhizal colonization and affects plant-soil feedback

Our aim was to study the effects of glyphosate, tilling practice and cultivation history on mycorrhizal colonization and growth of target (weeds) and non-target (crops) plants. Glyphosate, the world's most widely used pesticide, inhibits an enzyme found in plants but also in microbes. We examined the effects of glyphosate treatment applied in the preceding fall on growth of a perennial weed, Elymus repens (target plant) and a forage grass, Festuca pratensis (non-target plant) and their arbuscular mycorrhizal fungal (AMP) root colonization in a field pot experiment. Nontarget plants were sown in the following spring. Furthermore, we tested if glyphosate effects depend on tillage or soil properties modulated by long cultivation history of endophyte symbiotic grass (E+ grass). AM' root colonization, plant establishment and growth, glyphosate residues in plants, and soil chemistry were measured. Glyphosate reduced the mycorrhizal colonization and growth of both target and non-target grasses. The magnitude of reduction depended on tillage and soil properties due to cultivation history of E+ grass. We detected glyphosate residues in weeds and crop plants in the growing season following the glyphosate treatment. Residues were higher in plants growing in no-till pots compared to conspecifics in tilled pots. These results demonstrate negative effects of glyphosate on non-target organisms in agricultural environments and grassland ecosystems. (C) 2018 The Authors. Published by Elsevier B.V

Arbuscular mycorrhizal fungi can shift plant-soil feedback of grass-endophyte symbiosis from negative to positive

Aims: Plants affect each other by modifying soils conditions in plant-soil feedbacks, where associated microbes have an integral role. Since epichloid endophytes and arbuscular mycorrhizal fungi (AMF) are highly widespread grass symbionts, here we explore the role of AMF and endophyte in plant-soil feedback within the same grass population.Methods: Through a manipulative experiment, we evaluated the performance of endophyte-free and endophyte-associated Lolium multiflorum plants grown in soils previously conditioned by endophyte-free and endophyte-associated plants and inoculated or not with three AMF species.Results: The biomass of endophyte-free and endophyte-associated plants was increased by AMF inoculation, when growing in soils conditioned by equal endophytic status plants (i.e. home soils). When growing in soils conditioned by plants with different endophytic status, plant biomass was higher than in home soil only in absence of AMF. The content of P and the arbuscular colonization also increased in plants growing in home soils.Conclusion: We demonstrated that AMF shift the intraspecific feedback effects between E+ and E- conspecific plants from negative to positive. Furthermore, we found that the outcome of simultaneous occurrence of foliar and root symbionts on grass performance depends on the matching with the endophytic status of the previous plant.Fil: Garcia Parisi, Pablo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Broad-scale variation of fungal-endophyte incidence in temperate grasses

1.The strength of many interactions between plants and other organisms changes across regional gradients. For example, the relevance of plant-herbivore interactions increases with primary production. Likewise, biotic interactions collectively become more intense from the poles to the equator. Yet, the regional variation of the interaction between grasses and systemic fungal endophytes, which provide resistance to biotic and abiotic environmental factors (i.e. herbivory and drought), is poorly understood.2. We compiled 1008 records of the incidence level of fungal endophytes (Epichlo?e, Ascomycetes: Clavicipitaceae) on wild populations of 48 cool season grasses, encompassing 10 biomes across a broad latitudinal expanse and primary production gradient. Symbiosis incidence was analysed as a function of mean primary production, precipitation, temperature and latitude of each site, which in turn were obtained from climatic and satellital sources.3. Across a 30-fold variation of mean primary production, average symbiosis incidence increased from 20% to 70%. The pattern became stronger when the analysis was restricted to the single grass genus Festuca, which accounted for half of the total data.4. The number of grass populations showing no symbiosis incidence (0%) decreased as primary production increased, whereas those with 100% of incidence increased.5. Primary production at the regional scale was negatively correlated with latitude but positively with mean annual temperature and precipitation. Symbiosis incidence was similarly correlated with latitude and temperature, and it was not with mean annual precipitation. 6. Synthesis. Different descriptors of this grass-fungus symbiosis show that average incidence in wild populations world-wide increases with mean primary production. As at large spatial scales herbivory and temperature increase and aridity decreases with primary production, our results suggest that, at broad-scales, these biotic and abiotic factors may be important drivers of the symbiosis success.Fil: Semmartin, María Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Gundel, Pedro Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Hernández Agramonte, Ignacio M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin