Una sociedad con mucho para brindar

Muchas veces desconocemos la importancia de aquello que no podemos observar a simple vista. Los invitamos a conocer a las micorrizas, una simbiosis fundamental para el desarrollo vegetal y con gran potencial en producción forestal.Fil: Fernández, Natalia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Fontenla, Sonia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentin

Natives helping foreigners? The effect of inoculation of poplar with patagonian beneficial microorganisms

Inoculation with microorganisms represents an opportunity to enhance tree production, directly affecting plant growth or survival at planting. The aim of the present study was to evaluate the effect of mixed inoculation with native mycorrhizae, two yeasts and one endophytic bacterium, on the growth of two poplar clones commonly used in Patagonia, Argentina. Yeasts and bacteria were selected base on their ability to produce IAA and siderophores, as well as P solubilization in-vitro. A greenhouse trial was performed using hardwood cuttings of Populus nigra ‘Italica’ and Populus trichocarpa ‘SP1456’. Only yeasts modified growth traits, in a host-related response: Tausonia pullulans reduced the root/shoot ratio in P. nigra, and Candida saitoana and increased shoot dry biomass in P. trichocarpa. All plants presented arbuscular mycorrhizal colonization but ectomycorrhizae were absent. Two types of arbuscular mycorrhizal colonization were observed, one of them similar to Glomus tenue. We found a tendency for a higher percentage of arbuscular mycorrhizal colonization when plants were inoculated with T. pullulans. The used of native yeast along with mycorrhizal inocula appears to be a promising tool to improve poplar forestry.EEA BarilocheFil: Mestre, María Cecilia. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; ArgentinaFil: Pastorino, Mario Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte; ArgentinaFil: Aparicio, Alejandro Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentin

Ectomycorrhizas naturally established in Nothofagus nervosa seedlings under different cultivation practices in a forest nursery

Mycorrhizas are mutualistic associations between soil fungi and plant roots which usually improve water and nutrient uptake, influencing plant fitness. Nothofagus nervosa (Raulí) is an ecologically and economically important species of South American temperate forests. Since this native tree species yields valuable timber, it was overexploited and its natural distribution area was critically reduced, so it is currently included in domestication and conservation programs. Among the factors that should be considered in these programs are the ectomycorrhizas (EcM), which would be important for the successful establishment and survival of outplanted seedlings. The aim of this work was to analyze the abundance and diversity of EcM in N. nervosa nursery-cultivated seedlings assessed by morphotyping, fungal isolation, and DNA sequencing. Arbuscular mycorrhiza (AM) occurrence was also studied. A 2-year trial was conducted following the cultivation conditions used for domestication programs. Seedlings were cultivated under two different cultivation practices (greenhouse and nursery soil) without artificial inoculation of mycorrhizal fungi. Seedlings’ roots were examined at different times. It was observed that they developed EcM between 6 and 12 months after germination and AMs were not detected in any plant. The most abundant ectomycorrhizal fungi present in seedlings’ roots were Tomentella ellisii (Basidiomycota) and an unidentified fungus named Ascomicetous EcM sp. 1. Abundance and diversity of EcM varied between the two cultivation techniques analyzed in this study, since seedlings that continued growing in the greenhouse had higher colonization values, but those transplanted to the nursery soil were colonized by a higher diversity of fungal taxa.EEA BarilocheFil: Fernández, Natalia Verónica. Universidad Nacional del Comahue. Centro Regional Universidad de Bariloche. Departamento de Biologia. Laboratorio de Microbiologia Aplicada y Biotecnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Unidad de Genética Ecológica y Mejoramiento Forestal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentin

Environmental Conditions and Grazing Exerted Effects on Arbuscular Mycorrhizal in Plants at Southern Patagonia Rangelands

Arbuscular mycorrhizal (AM) fungi play a major role in maintaining ecosystem functions. AM fungi are found in most ecosystems including rangelands currently under increasing pressures from human activities. Southern Patagonia (Argentina) is a semiarid region influenced by extensive livestock production in rangelands. There is a lack of information about the environmental conditions and functionality of AM fungi in plant species of Patagonia ecosystems associated with livestock grazing. We assessed how soil properties, climatic conditions, and grazing intensities influence the response of AM fungi colonization. We studied most palatable and representative plant species (Poa dusenii, Rytidosperma virescens, Festuca gracillima, Nardophylum bryoides, Mulguraea tridens, and Carex argentina) growing in main ecological areas of Southern Patagonia. Most of the studied plant species (except C. argentina) presented AM symbiosis. AM colonization showed a negative relationship with soil organic carbon and nitrogen and a positive relationship with soil bulk density and pH. Results suggest that plants promoted a higher root AM colonization when soil nutrients and water availability (rainfall) are limiting. Sheep stocking rates had a differential impact depending on the ecological areas and plant life forms. High grazing decreased the AM colonization in the ecological areas with palatable plant dominance, suggesting that the impacts of grazing could lead to further negative effects on the ecosystem. Moderate grazing allows to maintain higher AM colonization, which would probably benefit the aboveground production of palatable plant and, consequently, to herbivores, particularly in degraded rangelands like Patagonian steppes. This study improves the knowledge of AM association in Patagonian semiarid rangelands by increasing our understanding of the impacts of grazing on belowground ecology. This information becomes relevant for grazing sustainable management, which may contribute to food security.EEA Santa CruzFil: Toledo, Santiago. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Toledo, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. CIT Santa Cruz; Argentina.Fil: Toledo, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Fontenla, Sonia B. Universidad Nacional del Comahue. Laboratorio de Biotecnología y Microbiologia Aplicad; Argentina

Effect of defoliation frequency on Rytidosperma virescens plants and arbuscular mycorrhizal fungi colonization

Rangelands provide different ecosystem services to satisfy human needs. Although grazing management in southern Patagonia is mostly characterized by extensive continuous grazing, rotational grazing management may improve plant productivity and its associated microbiome. Arbuscular mycorrhizal (AM) symbioses play an important role in the functioning of arid rangelands. However, in most arid and semiarid grasslands, little is known about the environment-plant-symbiont interaction under different defoliation frequencies and contrasting growth conditions. In this context, the objective of the present study was to evaluate the response of Rytidosperma virescens native grass and the associated AM fungi under different defoliation frequency treatments (plants undefoliated, two clippings with 50-d intervals between defoliations, four clippings with 30-d intervals, and six clippings with 21-d intervals) and two growth conditions (field and greenhouse) in a 150-d experiment. Defoliation frequency with 21-d clipping intervals negatively affected plants and AM colonization. We found a negative linear relationship between AM colonization and removal of aboveground biomass and a positive relationship with root biomass and leaf area of R. virescens plants. We determined that the appropriate recovery period for rotational grazing systems should be at least 50 d (threshold) to optimize forage production and AM symbiosis during spring-summer seasons. Sustainable grazing management practices should be designed to improve or restore AM communities to maintain positive feedback with plant development.EEA Santa CruzFil: Toledo, Santiago. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Toledo, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. CIT Santa Cruz; Argentina.Fil: Toledo, Santiago: Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Laboratorio de Biotecnología y Microbiología Aplicada; Argentina.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Occurrence of arbuscular mycorrhizas and dark septate endophytes in pteridophytes from a patagonian rainforest, Argentina

Arbuscular mycorrhizas (AM) are one of the most widespread types of symbiotic associations. Pteridophytes occupy an important position in the evolution of vascular plants. However, their mycorrhizal state remains poorly understood. The aim of this work was to describe the general mycorrhizal status and the occurrence of dark septate endophytes (DSE) in the pteridophytic flora of a Valdivian temperate forest in Patagonia, Argentina. First, the roots of nine terrestrial species representing six families were examined, and this information was then compared with other surveys concerning the occurrence of AM in other pteridophytic species within the same Valdivian temperate forest. Arbuscular mycorrhizas were recorded in 98.6% of the samples analyzed in this work and all of them corresponded to the Paris-type morphology. Dark septate endophytes were also present within the roots of all terrestrial species. A comparison to published results in other ferns and lycophytes that have been studied in this Valdivian temperate forest (161 sporophytes, 21 species and 10 families) was made. Clear differences in colonization patterns between eusporangiate/leptosporangiate and epiphytic/terrestrial species became evident and are discussed.Fil: Fernández, Natalia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; ArgentinaFil: Messuti, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; ArgentinaFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentin

Yeast and yeast‐like fungi associated with dry indehiscent fruits of Nothofagus nervosa in Patagonia, Argentina

Nothofagus nervosa (Raulí) is a native tree species that yields valuable timber. It was overexploited in the past and is currently included in domestication and conservation programs. Several research programs have focused on the characterization of epiphytic microorganisms because it has been demonstrated that they can affect plant–pathogen interactions and/or promote plant growth. Although the microbial ecology of leaves has been well studied, less is known about microorganisms occurring on seeds and noncommercial fruits. In this work, we analyzed the yeast and yeast‐like fungi present on N. nervosa fruits destined for the propagation of this species, as well as the effects of fruit preservation and seed dormancy‐breaking processes on fungal diversity. Morphological and molecular methods were used, and differences between fungal communities were analyzed using a similarity index. A total of 171 isolates corresponding to 17 species were recovered, most of which belong to the phylum Ascomycota. The majority of the species develop mycelia, produce pigments and mycosporines, and these adaptation strategies are discussed. It was observed that the preservation process considerably reduced yeast and yeast‐like fungal diversity. This is the first study concerning microbial communities associated with this ecologically and economically important species, and the information presented is relevant to domestication programs.EEA BarilocheFil: Fernández, Natalia Verónica. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mestre, María Cecilia. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Unidad de Genética Ecológica y Mejoramiento Forestal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentin

Are the rhizosphere fungal communities of Nothofagus alpina established in two different environments influenced by plant genetic diversity?

Fungi are one of the most important soil microorganisms due to their abundance and the importance of the ecosystem processes they carry out, like decomposition, nutrient cycling, and the establishment of biological interactions such as mycorrhizas. Fungi can be used as bioindicators because they are highly sensitive to alterations in their surroundings, thus being useful for monitoring ecological changes and effects of human activity on natural ecosystems. Nothofagus alpina (raulí) is an ecologically and economically important species of South American temperate forests. It is currently included in domestication and conservation programs, and provenance trials have been installed in different ecosystems of Patagonia. These trials are ideal for studying how tree genetics might influence the associated microbiota. Afforestation with fast-growing exotic conifers (mainly Pinus ponderosa) had been promoted as an important economic activity in Patagonia, but nowadays there is an increasing interest for the establishment of mix Pinus + Nothofagus plantations instead of monospecific Pinus stands and for using Pinus plantations as refugee for assisted Nothofagus migration. The main objective of this work was to explore the structure of different fungal communities in the rhizosphere of N. alpina with different genetic diversity (high, intermediate, and low) implanted under a native Nothofagus forest and a P. ponderosa plantation. Fingerprinting based on Temperature Gradient Gel Electrophoresis revealed differences in the structure of the rhizosphere fungal communities. Some relationships between N. alpina genetic diversity and composition of rhizosphere fungal communities were observed. In the native forest, one of the provenances (intermediate genetic diversity) was associated with the highest richness of Basidiomycetes and total fungi. In addition, individual genetic parameters of N. alpina specimens implanted in the native forest significantly correlated with Ascomycetes richness. It was also found that Basidiomycetes were the dominating fungal taxa in the native forest, and Ascomycetes in the P. ponderosa plantation. Factors as soil physicochemical characteristics and the dominant forestry species, which provide different quantity and quality of litter inputs and are associated with different ectomycorrhizal fungi, seemed to be the main factors determining this significant difference between the native forest and the plantation. Beyond highlighting the potential of applying soil fungi as bioindicators, our study contributes to understanding the relationship between host genetics and rhizosphere fungi. This information is relevant not only for conservation and restoration programs, but also for taking management decisions related with sustainable forestry and domestication of native tree species.Estación Experimental Agropecuaria BarilocheFil: Fernandez, Natalia Veronica. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Tenreiro, Rogério. Universidade de Lisboa. Faculdade de Ciências, Biosystems and Integrative Sciences Institute; PortugalFil: Chaves, Sandra. Universidade de Lisboa. Faculdade de Ciências, Biosystems and Integrative Sciences Institute; PortugalFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Microbiología Aplicada y Biotecnología; Argentin

Raulí (Nothofagus alpina = N. nervosa): The Best Quality Hardwood in Patagonia

Nothofagus alpina (Poepp. and Endl.) Oerst. (= N. nervosa (Phil.) Dim. et Mil.), raulí, is an iconic forest tree species of the South American temperate forests due to its hardwood quality. With a pinkish colour and light red tints, raulí’s wood is very appreciated in the regional and international market for its excellent physical and mechanical characteristics. The texture is fine and homogeneous, presenting a very smooth veining with linear fibres that allow obtaining even excellent roof tiles and a density of approximately 0.55 g/cm3 at 12% moisture content. Easy to dry, once dry it is dimensionally stable, easy to saw, brush and turn, achieving excellent terminations and therefore very suitable for door and window frames, furniture and fine woodwork (Diaz-Vaz 1987). Owing to this superb wood quality, raulí has been extensively logged, mainly during the first half of the twentieth century, causing a dramatic reduction of its forests (Donoso and Lara 1995; Gonzalez Peñalba et al. 1997).Estación Experimental Agropecuaria BarilocheFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Marchelli, Paula. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Pastorino, Mario Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Pastorino, Mario Juan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Azpilicueta, Maria Marta. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Azpilicueta, Maria Marta. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Duboscq Carra, Virginia Gisela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Duboscq Carra, Virginia Gisela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Sola, Georgina Giselle. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Sola, Georgina Giselle. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: El Mujtar, Veronica Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: El Mujtar, Veronica Andrea. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Arana, María Veronica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Arana, María Veronica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Arias Rios, Jorge Andrés. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Arias Rios, Jorge Andrés. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Fernandez, Natalia. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Instituto Andino Patagónico de Tecnologias Biologicas; ArgentinaFil: Fontenla, Sonia Beatriz. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Instituto Andino Patagónico de Tecnologias Biologicas; ArgentinaFil: González Peñalba, Marcelo. Administración de Parques Nacionales. Parque Nacional Lanín; ArgentinaFil: Gallo, Leonardo Ariel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Gallo, Leonardo Ariel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; Argentin