Trends in Antarctic soil fungal research in the context of environmental changes.

Antarctic soils represent one of the most pristine environments on Earth, where highly adapted and often endemic microbial species withstand multiple extremes. Specifically, fungal diversity is extremely low in Antarctic soils and species distribution and diversity are still not fully characterized in the continent. Despite the unique features of this environment and the international interest in its preservation, several factors pose severe threats to the conservation of inhabiting ecosystems. In this light, we aimed to provide an overview of the effects on fungal communities of the main changes endangering the soils of the continent. Among these, the increasing human presence, both for touristic and scientific purposes, has led to increased use of fuels for transport and energy supply, which has been linked to an increase in unintentional environmental contamination. It has been reported that several fungal species have evolved cellular processes in response to these soil contamination episodes, which may be exploited for restoring contaminated areas at low temperatures. Additionally, the effects of climate change are another significant threat to Antarctic ecosystems, with the expected merging of previously isolated ecosystems and their homogenization. A possible reduction of biodiversity due to the disappearance of well-adapted, often endemic species, as well as an increase of biodiversity, due to the spreading of non-native, more competitive species have been suggested. Despite some studies describing the specialization of fungal communities and their correlation with environmental parameters, our comprehension of how soil communities may respond to these changes remains limited. The majority of studies attempting to precisely define the effects of climate change, including in situ and laboratory simulations, have mainly focused on the bacterial components of these soils, and further studies are necessary, including the other biotic components.

Amazonian soil fungi are efficient degraders of glyphosate herbicide; novel isolates of Penicillium, Aspergillus, and Trichoderma / Os fungos do solo amazônico são degradadores eficientes do herbicida glifosato; novos isolados de Penicillium, Aspergillus e Trichoderma

Pesticide residues that contaminate the environment circulate within the hydrological cycle can accumulate within the food chain and cause problems to both environmental and human health. Microbes, however, are well known for their metabolic versatility and the ability to degrade chemically stable substances, including recalcitrant xenobiotics. The current study focused on bio-prospecting within Amazonian rainforest soils to find novel strains fungi capable of efficiently degrading the agriculturally and environmentally ubiquitous herbicide, glyphosate. Of 50 fungal strains isolated (using culture media supplemented with glyphosate as the sole carbon-substrate), the majority were Penicillium strains (60%) and the others were Aspergillus and Trichoderma strains (26 and 8%, respectively). All 50 fungal isolates could use glyphosate as a phosphorous source. Eight of these isolates grew better on glyphosate-supplemented media than on regular Czapek Dox medium. LC-MS revealed that glyphosate degradation by Penicillium 4A21 resulted in sarcosine and aminomethylphosphonic acid.(AU)

Resíduos de agrotóxicos que contaminam o meio ambiente circulam no ciclo hidrológico, podendo se acumular na cadeia alimentar e causar problemas tanto à saúde ambiental quanto humana. Por sua vez, microrganismos são bem conhecidos por sua versatilidade metabólica e capacidade de degradar substâncias quimicamente estáveis, incluindo xenobióticos recalcitrantes. O estudo atual se concentrou na bioprospecção nos solos da floresta amazônica para encontrar novas linhagens de fungos capazes de degradar com eficiência o herbicida onipresente na agricultura e no meio ambiente, o glifosato. Entre os 50 fungos isolados (usando meio de cultura suplementado com glifosato como única fonte de carbono), a maioria eram isolados do gênero Penicillium (60%) e os outros eram isolados de Aspergillus e Trichoderma (26 e 8%, respectivamente). Todos os 50 isolados de fungos foram capazes de usar glifosato como fonte de fósforo. Oito desses isolados cresceram melhor em meio suplementado com glifosato do que em meio Czapek Dox regular. LC-MS revelou que a degradação do glifosato por Penicillium 4A21 resultou nos metabólitos sarcosina e ácido aminometilfosfônico.(AU)

Amazonian soil fungi are efficient degraders of glyphosate herbicide; novel isolates of Penicillium, Aspergillus, and Trichoderma / Os fungos do solo amazônico são degradadores eficientes do herbicida glifosato; novos isolados de Penicillium, Aspergillus e Trichoderma

Pesticide residues that contaminate the environment circulate within the hydrological cycle can accumulate within the food chain and cause problems to both environmental and human health. Microbes, however, are well known for their metabolic versatility and the ability to degrade chemically stable substances, including recalcitrant xenobiotics. The current study focused on bio-prospecting within Amazonian rainforest soils to find novel strains fungi capable of efficiently degrading the agriculturally and environmentally ubiquitous herbicide, glyphosate. Of 50 fungal strains isolated (using culture media supplemented with glyphosate as the sole carbon-substrate), the majority were Penicillium strains (60%) and the others were Aspergillus and Trichoderma strains (26 and 8%, respectively). All 50 fungal isolates could use glyphosate as a phosphorous source. Eight of these isolates grew better on glyphosate-supplemented media than on regular Czapek Dox medium. LC-MS revealed that glyphosate degradation by Penicillium 4A21 resulted in sarcosine and aminomethylphosphonic acid.

Resíduos de agrotóxicos que contaminam o meio ambiente circulam no ciclo hidrológico, podendo se acumular na cadeia alimentar e causar problemas tanto à saúde ambiental quanto humana. Por sua vez, microrganismos são bem conhecidos por sua versatilidade metabólica e capacidade de degradar substâncias quimicamente estáveis, incluindo xenobióticos recalcitrantes. O estudo atual se concentrou na bioprospecção nos solos da floresta amazônica para encontrar novas linhagens de fungos capazes de degradar com eficiência o herbicida onipresente na agricultura e no meio ambiente, o glifosato. Entre os 50 fungos isolados (usando meio de cultura suplementado com glifosato como única fonte de carbono), a maioria eram isolados do gênero Penicillium (60%) e os outros eram isolados de Aspergillus e Trichoderma (26 e 8%, respectivamente). Todos os 50 isolados de fungos foram capazes de usar glifosato como fonte de fósforo. Oito desses isolados cresceram melhor em meio suplementado com glifosato do que em meio Czapek Dox regular. LC-MS revelou que a degradação do glifosato por Penicillium 4A21 resultou nos metabólitos sarcosina e ácido aminometilfosfônico.

Amazonian soil fungi are efficient degraders of glyphosate herbicide; novel isolates of Penicillium, Aspergillus, and Trichoderma / Os fungos do solo amazônico são degradadores eficientes do herbicida glifosato; novos isolados de Penicillium, Aspergillus e Trichoderma

Abstract Pesticide residues that contaminate the environment circulate within the hydrological cycle can accumulate within the food chain and cause problems to both environmental and human health. Microbes, however, are well known for their metabolic versatility and the ability to degrade chemically stable substances, including recalcitrant xenobiotics. The current study focused on bio-prospecting within Amazonian rainforest soils to find novel strains fungi capable of efficiently degrading the agriculturally and environmentally ubiquitous herbicide, glyphosate. Of 50 fungal strains isolated (using culture media supplemented with glyphosate as the sole carbon-substrate), the majority were Penicillium strains (60%) and the others were Aspergillus and Trichoderma strains (26 and 8%, respectively). All 50 fungal isolates could use glyphosate as a phosphorous source. Eight of these isolates grew better on glyphosate-supplemented media than on regular Czapek Dox medium. LC-MS revealed that glyphosate degradation by Penicillium 4A21 resulted in sarcosine and aminomethylphosphonic acid.

Resumo Resíduos de agrotóxicos que contaminam o meio ambiente circulam no ciclo hidrológico, podendo se acumular na cadeia alimentar e causar problemas tanto à saúde ambiental quanto humana. Por sua vez, microrganismos são bem conhecidos por sua versatilidade metabólica e capacidade de degradar substâncias quimicamente estáveis, incluindo xenobióticos recalcitrantes. O estudo atual se concentrou na bioprospecção nos solos da floresta amazônica para encontrar novas linhagens de fungos capazes de degradar com eficiência o herbicida onipresente na agricultura e no meio ambiente, o glifosato. Entre os 50 fungos isolados (usando meio de cultura suplementado com glifosato como única fonte de carbono), a maioria eram isolados do gênero Penicillium (60%) e os outros eram isolados de Aspergillus e Trichoderma (26 e 8%, respectivamente). Todos os 50 isolados de fungos foram capazes de usar glifosato como fonte de fósforo. Oito desses isolados cresceram melhor em meio suplementado com glifosato do que em meio Czapek Dox regular. LC-MS revelou que a degradação do glifosato por Penicillium 4A21 resultou nos metabólitos sarcosina e ácido aminometilfosfônico.

Amazonian soil fungi are efficient degraders of glyphosate herbicide; novel isolates of Penicillium, Aspergillus, and Trichoderma

Abstract Pesticide residues that contaminate the environment circulate within the hydrological cycle can accumulate within the food chain and cause problems to both environmental and human health. Microbes, however, are well known for their metabolic versatility and the ability to degrade chemically stable substances, including recalcitrant xenobiotics. The current study focused on bio-prospecting within Amazonian rainforest soils to find novel strains fungi capable of efficiently degrading the agriculturally and environmentally ubiquitous herbicide, glyphosate. Of 50 fungal strains isolated (using culture media supplemented with glyphosate as the sole carbon-substrate), the majority were Penicillium strains (60%) and the others were Aspergillus and Trichoderma strains (26 and 8%, respectively). All 50 fungal isolates could use glyphosate as a phosphorous source. Eight of these isolates grew better on glyphosate-supplemented media than on regular Czapek Dox medium. LC-MS revealed that glyphosate degradation by Penicillium 4A21 resulted in sarcosine and aminomethylphosphonic acid.

Resumo Resíduos de agrotóxicos que contaminam o meio ambiente circulam no ciclo hidrológico, podendo se acumular na cadeia alimentar e causar problemas tanto à saúde ambiental quanto humana. Por sua vez, microrganismos são bem conhecidos por sua versatilidade metabólica e capacidade de degradar substâncias quimicamente estáveis, incluindo xenobióticos recalcitrantes. O estudo atual se concentrou na bioprospecção nos solos da floresta amazônica para encontrar novas linhagens de fungos capazes de degradar com eficiência o herbicida onipresente na agricultura e no meio ambiente, o glifosato. Entre os 50 fungos isolados (usando meio de cultura suplementado com glifosato como única fonte de carbono), a maioria eram isolados do gênero Penicillium (60%) e os outros eram isolados de Aspergillus e Trichoderma (26 e 8%, respectivamente). Todos os 50 isolados de fungos foram capazes de usar glifosato como fonte de fósforo. Oito desses isolados cresceram melhor em meio suplementado com glifosato do que em meio Czapek Dox regular. LC-MS revelou que a degradação do glifosato por Penicillium 4A21 resultou nos metabólitos sarcosina e ácido aminometilfosfônico.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study / ¿Los hongos endófitos septados oscuros (DSE) pueden movilizar selectivamente el fósforo inorgánico y promover así el crecimiento del sorgo? Un estudio preliminar

Abstract Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Resumen Los fertilizantes fosfatados tienden a precipitar con componentes del suelo, lo que afecta la eficiencia de la fertilización y causa efectos negativos. Para resolver este problema se han utilizado microorganismos del suelo. Sin embargo, no se conoce bien la capacidad de los hongos endófitos septados oscuros (ESO) para disolver fosfatos y aumentar el rendimiento de los cultivos. Se estudió en un hapludol típico (typic hapludoll) la actividad de hongos ESO capaces de solubilizar fosfatos de grado reactivo. Se evaluó el efecto de los hongos sobre las fracciones de fósforo inorgánico y se realizó un experimento en macetas con sorgo como cultivo. No se encontraron estructuras fúngicas en las raíces. Curvularia sp. aumentó la biomasa aérea y la longitud radical, pero la concentración de fósforo no se vio afectada. Aunque los resultados no son concluyentes, representan un avance en el uso potencial de hongos ESO como solubilizadores de fósforo para tratar la nutrición de cultivos.

Diversity of Root-Associated Fungi of the Terrestrial Orchids Gavilea lutea and Chloraea collicensis in a Temperate Forest Soil of South-Central Chile.

The diversity of orchid mycorrhizal fungi (OMF) and other beneficial root-associated fungi in temperate forests has scarcely been examined. This study aimed to analyze the diversity of mycorrhizal and rhizosphere-associated fungal communities in the terrestrial orchids Gavilea lutea and Chloraea collicensis growing in high-orchid-population-density areas in the piedmont of the Andes Cordillera with native forest (Nothofagus-Araucaria) and Coastal Cordillera with an exotic plantation (Pinus-Eucalyptus) in south-central Chile. We focused on rhizosphere-inhabiting and peloton-associated OMF in a native forest (Andes Cordillera) and a mixed forest (Coastal Cordillera). The native terrestrial orchids G. lutea and C. collicensis were localized, mycorrhizal root segments were taken to isolate peloton-associated OMF, and rhizosphere soil was taken to perform the metabarcoding approach. The results revealed that Basidiomycota and Ascomycota were the main rhizosphere-inhabiting fungal phyla, showing significant differences in the composition of fungal communities in both sites. Sebacina was the most-abundant OMF genera in the rhizosphere of G. lutea growing in the native forest soil. In contrast, Thanatephorus was the most abundant mycorrhizal taxa growing in the rhizosphere of orchids from the Coastal Cordillera. Besides, other OMF genera such as Inocybe, Tomentella, and Mycena were detected. The diversity of OMF in pelotons differed, being mainly related to Ceratobasidium sp. and Tulasnella sp. These results provide evidence of differences in OMF from pelotons and the rhizosphere soil in G. lutea growing in the Andes Cordillera and a selection of microbial communities in the rhizosphere of C. collicensis in the Coastal Cordillera. This raises questions about the efficiency of propagation strategies based only on mycorrhizal fungi obtained by culture-dependent methods, especially in orchids that depend on non-culturable taxa for seed germination and plantlet development.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study.

Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Efficiency of different strains of Trichoderma on the control of Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotium cepivorum

The aim of this work was to verify the efficiency of different isolates of Trichoderma spp.on the control of Sclerotiniasclerotiorum, Sclerotiumrolfsii and Sclerotiumcepivorum, and the influence they pose on the conidia production of Trichoderma spp.For mycelial growth, discs with inoculum of phytopathogens were placed on the center of the Petri dishes followed by the addition of two Trichodermasp. discs on the opposite sides of the plate after 24hours. Every 12hoursdata were collected from colonies diameters and used for the analyses of Mycelial Growth Index (MGI) and Area Under the Curve of Mycelial Growth (AUCMG). The analyses were performed by a completely randomized design with two controls, a negative one without Trichodermasp. and one with acommercial strain of Trichodermaharzianum. Spore solution for evaluation of conidia production were made by adding 10 mL of distilled water and scratching the surface of the colonies. For S. cepivorum, all Trichoderma spp. strains reduced both indexes tested. However, while for MGI S. sclerotiorum also presented some reduction on the growth rate, the total area of this fungus was not affected. Sclerotiumrolfsii strains of Trichodermasp. from Lages and Curitibanosshowed an effect on the reduction of AUCMG of this fungus, although none of the Trichodermaaffected the growth rate of this phytopathogen. On the presence of S. sclerotiorumand S. cepivorum, none of the Trichodermaspp. showed any difference on conidia production when compared among themselves, nonetheless we did notice that on the presence of S. cepivorum, the strain from Rio do Sul retained its reproductive ability compared to control. Results obtained from this research can demonstrate the importance of biocontrol agents against different plant pathogens since it might have a specific antagonist-pathogen relation.(AU)

Fungicidal potential of essential oils in control of Fusarium spp. and Sclerotinia sclerotiorum / Potencial fungicida de óleos essenciais no controle de Fusarium spp. e Sclerotinia sclerotiorum

The use of highly toxic pesticides to control soil pathogens, such as Fusarium spp. and Sclerotinia sclerotiorum has generated concern, due to the irreversible impacts caused on the environment, in addition to selecting resistant isolates. In this way, essential oils appear as an efficient alternative in control of diseases. Facing the problem of soil pathogens control and high antimicrobial fungicide that essential oils present, this work aimed to evaluate the in vitro fungicidal potential of essential oils in control of Fusarium spp. and S. sclerotiorum. A completely randomized design, factorial scheme 2×4×8 was used, with two isolates (Fusarium spp. and S. sclerotiorum), four essential oils (Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum), eight essential oil concentrations (0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 and 1.4 ?L·mL-1), and ten replicates. The essential oils inhibited mycelial growth of the fungi in different concentrations, being their potential justified by the presence of antifungal chemical compounds. Essential oils of A. citriodora, C. winterianus, L. alba and O. americanum present high fungicidal potential, being viable alternatives for formulation of commercial products, boosting the pesticides industry.(AU)

O uso de pesticidas com alta toxicidade para controlar patógenos do solo, como Fusarium spp. e Sclerotinia sclerotiorum, tem gerado preocupação, devido aos impactos irreversíveis causados no meio ambiente, além de selecionar isolados resistentes. Dessa forma, os óleos essenciais surgem como uma alternativa eficiente no controle de doenças. Diante da problemática de controle de patógenos do solo e alto potencial antimicrobiano que os óleos essenciais possuem, este trabalho teve como objetivo avaliar o potencial fungicida de óleos essenciais no controle de Fusarium spp. e S. sclerotiorum, in vitro. Utilizou-se um delineamento inteiramente randomizado, esquema fatorial 2×4×8, com dois isolados (Fusarium spp. e S. sclerotiorum), quatro óleos essenciais (Aloysia citriodora, Cymbopogon winterianus, Lippia alba e Ocimum americanum) e oito concentrações de óleo essencial (0,0; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2 e 1,4 ?L·mL-1), com dez repetições. Os óleos essenciais inibiram o crescimento micelial dos fungos em diferentes concentrações, sendo seu potencial justificado pela presença de compostos químicos antifúngicos. Os óleos essenciais de A. citriodora, C. winterianus, L. alba e O. americanum apresentam alto potencial fungicida, sendo alternativas viáveis para formulação de produtos comerciais, impulsionando a indústria de agrotóxicos.(AU)

Fungicidal potential of essential oils in control of Fusarium spp. and Sclerotinia sclerotiorum / Potencial fungicida de óleos essenciais no controle de Fusarium spp. e Sclerotinia sclerotiorum

The use of highly toxic pesticides to control soil pathogens, such as Fusarium spp. and Sclerotinia sclerotiorum has generated concern, due to the irreversible impacts caused on the environment, in addition to selecting resistant isolates. In this way, essential oils appear as an efficient alternative in control of diseases. Facing the problem of soil pathogens control and high antimicrobial fungicide that essential oils present, this work aimed to evaluate the in vitro fungicidal potential of essential oils in control of Fusarium spp. and S. sclerotiorum. A completely randomized design, factorial scheme 2×4×8 was used, with two isolates (Fusarium spp. and S. sclerotiorum), four essential oils (Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum), eight essential oil concentrations (0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 and 1.4 ?L·mL-1), and ten replicates. The essential oils inhibited mycelial growth of the fungi in different concentrations, being their potential justified by the presence of antifungal chemical compounds. Essential oils of A. citriodora, C. winterianus, L. alba and O. americanum present high fungicidal potential, being viable alternatives for formulation of commercial products, boosting the pesticides industry.(AU)

O uso de pesticidas com alta toxicidade para controlar patógenos do solo, como Fusarium spp. e Sclerotinia sclerotiorum, tem gerado preocupação, devido aos impactos irreversíveis causados no meio ambiente, além de selecionar isolados resistentes. Dessa forma, os óleos essenciais surgem como uma alternativa eficiente no controle de doenças. Diante da problemática de controle de patógenos do solo e alto potencial antimicrobiano que os óleos essenciais possuem, este trabalho teve como objetivo avaliar o potencial fungicida de óleos essenciais no controle de Fusarium spp. e S. sclerotiorum, in vitro. Utilizou-se um delineamento inteiramente randomizado, esquema fatorial 2×4×8, com dois isolados (Fusarium spp. e S. sclerotiorum), quatro óleos essenciais (Aloysia citriodora, Cymbopogon winterianus, Lippia alba e Ocimum americanum) e oito concentrações de óleo essencial (0,0; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2 e 1,4 ?L·mL-1), com dez repetições. Os óleos essenciais inibiram o crescimento micelial dos fungos em diferentes concentrações, sendo seu potencial justificado pela presença de compostos químicos antifúngicos. Os óleos essenciais de A. citriodora, C. winterianus, L. alba e O. americanum apresentam alto potencial fungicida, sendo alternativas viáveis para formulação de produtos comerciais, impulsionando a indústria de agrotóxicos.(AU)

Root-Associated Fungal Communities in Two Populations of the Fully Mycoheterotrophic Plant Arachnitis uniflora Phil. (Corsiaceae) in Southern Chile.

The microbiological interactions of the roots of non-photosynthetic plants in South America have been scarcely explored. This study analyzes culturable fungal diversity associated with the mycoheterotrophic plant Arachnitis uniflora Phil. (Corsiaceae) in southern Chile, growing in two different understoreys of native (Nothofagus-dominated) and mixed forest (native, Cupressus sempervirens, and Pinus radiata). Rhizospheric and endophytic fungi were isolated, cultured, and purified to identify microorganisms associated with A. uniflora roots. We showed the different fungi associated with the plant, and that these distributions are influenced by the sampling site. We isolated 410 fungal strains (144 endophytic and 266 from the rhizosphere). We identified 13 operative taxonomical units from plants sampled in the mixed forest, while 15 were from the native forest. Rhizospheric microorganisms were mainly related to Penicillium spp., whereas some pathogenic and saprophytic strains were more frequent inside the roots. Our results have also shown that the fungal strains are weak for phosphate solubilization, but other pathways such as organic acid exudation and indole acetic acid production can be considered as major mechanisms to stimulate plant growth. Our results point to new fungal associates of A. uniflora plants reported in Andean ecosystems, identifying new beneficial endophytic fungi associated with roots of this fully mycoheterotrophic plant.

Conceptos fundamentales en ecología de hongos del suelo: una propuesta pedagógica y de divulgación / Fundamental concepts in ecology of soil fungi: a pedagogic and outreach proposal

El estudio de los procesos biogeoquímicos implica entender cómo los macro y micro nutrientes que componen los seres vivos se mueven de un componente a otro del ecosistema (incluyendo la atmósfera, organismos, suelo, cuerpos de agua, etc.). Usualmente, una mayor diversidad biótica y una mayor complejidad de las interacciones bióticas y abióticas, resultan en una mayor estabilidad ecosistémica. El rol de los hongos en los ciclos biogeoquímicos se suele estudiar superficialmente, no mucho más allá de sus funciones ecosistémicas generales: descomposición, simbiosis mutualista, y parasitismo. Esta revisión tiene por objetivo ilustrar los conceptos base de los roles ecológicos de los hongos del suelo, que debieran enseñarse en tres públicos objetivo: universitario, tomadores de decisiones, y estudiantes de educación secundaria/público general. En estos públicos, se propone abordar cuatro áreas temáticas: introducción al suelo, ecología de comunidades, interacciones de hongos con otros organismos, y biogeoquímica. Aunque los roles ecosistémicos de los hongos del suelo están bien documentados, su estudio debería partir de la base de que estos afectan y son afectados tanto por variables climáticas, como por características físico-químicas del suelo, y por flujos biogeoquímicos. Los roles ecológicos de los hongos del suelo debieran entenderse en un contexto holístico de integración multidisciplinar, y el nivel de especialización del conocimiento debiera darse hacia niveles superiores de la jerarquía biológica, es decir, conocer más en detalle la ecología de ecosistemas y comunidades de hongos que la de poblaciones y organismos, o que sus procesos bioquímicos y edáficos específicos.

The study of biogeochemical processes involves understanding how the macro and micro nutrients that make up living things move from one ecosystem component to another (including the atmosphere, organisms, soil, waterbodies, etc.). Usually, a greater diversity of biotic diversity and a greater complexity of biotic and abiotic interactions, result in a greater ecosystemic stability. The role of fungi in biogeochemical cycles is usually studied superficially, not much beyond their general ecosystem functions: decomposition, mutualistic symbiosis, and parasitism. The objective of this review is to illustrate the basic concepts of the ecological roles of soil fungi, which should be taught in three target audiences: university students, decision makers, and secondary school students / general public. In these audiences, it is proposed to address four thematic areas: introduction to soil, community ecology, interactions of fungi with other organisms, and biogeochemistry. Although the ecosystemic roles of soil fungi are well documented, their study should be based on the fact that they affect and are affected by climatic variables, physical-chemical soil characteristics, and biogeochemical flows. The ecological roles of soil fungi should be understood in an holistic context of multidisciplinary integration, and the level of specialization of knowledge should be given to higher levels of the biological hierarchy, that is, to know more in detail the ecology of ecosystems and communities of fungi than that of populations and organisms, or than that of their specific biochemical and edaphic processes.

Antagonism of Trichoderma isolates against Leucoagaricus gongylophorus (Singer) Möller.

Filamentous fungi from the genus Trichoderma are commonly found in soil. They are considered facultative mycoparasites, and are antagonists of other fungi such as the cultivar of leaf-cutting ants (Leucoagaricus gongylophorus). The aim of the present study was to bioprospect Trichoderma spp. from different soils collected from Gurupi, Tocantins, Brazil, for antagonistic effects against the mutualistic fungus of leaf-cutting ants. To isolate filamentous fungi, samples were collected from six locations. Preliminarily, isolates were identified by morphological analysis as belonging to Trichoderma. Trichoderma spp. had their internal transcribed spacer region (ITS) of ribosomal RNA genes (rRNA) sequenced to confirm species-level taxonomy. L. gongylophorus was isolated from a laboratory ant colony. Antagonistic properties of seven isolates of Trichoderma against L. gongylophorus were measured using paired disks in Petri dishes with potato dextrose agar medium (PDA). All Trichoderma isolates inhibited the growth of L. gongylophorus in Petri dishes. Isolate 2 of Trichoderma spirale group exhibited slow mycelial growth in the Petri dish, and a high rate of inhibition against L. gongylophorus. This isolate is a promising fungus for field tests of biological control methods for leaf-cutting ants.

The Role of Hydrophobicity and Surface Receptors at Hyphae of Lyophyllum sp. Strain Karsten in the Interaction with Burkholderia terrae BS001 - Implications for Interactions in Soil.

The soil bacterium Burkholderia terrae strain BS001 can interact with varying soil fungi, using mechanisms that range from the utilization of carbon/energy sources such as glycerol to the ability to reach novel territories in soil via co-migration with growing fungal mycelia. Here, we investigate the intrinsic properties of the B. terrae BS001 interaction with the basidiomycetous soil fungus Lyophyllum sp. strain Karsten. In some experiments, the ascomycetous Trichoderma asperellum 302 was also used. The hyphae of Lyophyllum sp. strain Karsten were largely hydrophilic on water-containing media versus hydrophobic when aerial, as evidenced by contact angle analyses (CA). Co-migration of B. terrae strain BS001 cells with the hyphae of the two fungi occurred preferentially along the - presumably hydrophilic - soil-dwelling hyphae, whereas aerial hyphae did not allow efficient migration, due to reduced thickness of their surrounding mucous films. Moreover, the cell numbers over the length of the hyphae in soil showed an uneven distribution, i.e., the CFU numbers increased from minima at the inoculation point to maximal numbers in the middle of the extended hyphae, then decreasing toward the terminal side. Microscopic analyses of the strain BS001 associations with the Lyophyllum sp. strain Karsten hyphae in the microcosms confirmed the presence of B. terrae BS001 cells on the mucous matter that was present at the hyphal surfaces of the fungi used. Cell agglomerates were found to accumulate at defined sites on the hyphal surfaces, which were coined 'fungal-interactive' hot spots. Evidence was further obtained for the contention that receptors for a physical bacterium-fungus interaction occur at the Lyophyllum sp. strain Karsten hyphal surface, in which the specific glycosphingolipid ceramide monohexoside (CMH) plays an important role. Thus, bacterial adherence may be mediated by heterogeneously distributed fungal-specific receptors, implying the CMH moieties. This study sheds light on the physical aspects of the B. terrae BS001 - Lyophyllum sp. strain Karsten interaction, highlighting heterogeneity along the hyphae with respect to hydrophobicity and the presence of potential anchoring sites.

Long-lasting effects of land use history on soil fungal communities in second-growth tropical rain forests.

Our understanding of the long-lasting effects of human land use on soil fungal communities in tropical forests is limited. Yet, over 70% of all remaining tropical forests are growing in former agricultural or logged areas. We investigated the relationship among land use history, biotic and abiotic factors, and soil fungal community composition and diversity in a second-growth tropical forest in Puerto Rico. We coupled high-throughput DNA sequencing with tree community and environmental data to determine whether land use history had an effect on soil fungal community descriptors. We also investigated the biotic and abiotic factors that underlie such differences and asked whether the relative importance of biotic (tree diversity, basal tree area, and litterfall biomass) and abiotic (soil type, pH, iron, and total carbon, water flow, and canopy openness) factors in structuring soil fungal communities differed according to land use history. We demonstrated long-lasting effects of land use history on soil fungal communities. At our research site, most of the explained variation in soil fungal composition (R2  = 18.6%), richness (R2  = 11.4%), and evenness (R2  = 10%) was associated with edaphic factors. Areas previously subject to both logging and farming had a soil fungal community with lower beta diversity and greater evenness of fungal operational taxonomic units (OTUs) than areas subject to light logging. Yet, fungal richness was similar between the two areas of historical land use. Together, these results suggest that fungal communities in disturbed areas are more homogeneous and diverse than in areas subject to light logging. Edaphic factors were the most strongly correlated with soil fungal composition, especially in areas subject to light logging, where soils are more heterogenous. High functional tree diversity in areas subject to both logging and farming led to stronger correlations between biotic factors and fungal composition than in areas subject to light logging. In contrast, fungal richness and evenness were more strongly correlated with biotic factors in areas of light logging, suggesting that these metrics might reflect long-term associations in old-growth forests. The large amount of unexplained variance in fungal composition suggests that these communities are structured by both stochastic and niche assemblage processes.

Unexpectedly High Beta-Diversity of Root-Associated Fungal Communities in the Bolivian Andes.

Bolivia is one of the most biologically diverse countries on the planet. Between the Andes and the Amazon drainage basin spans the Yungas, a vast forested region shown to be extremely species rich in macro-organisms. However, it remains unclear whether this high diversity is also reflected in microbial diversity. Here we assess the genetic, taxonomic and functional diversity of root-associated fungi surrounding Cinchona calisaya trees, a typical element of the intermediate altitudes of the Bolivian Yungas. We determine the relative effects of edaphic properties, climate, and geography in regulating fungal community assembly. We show that α-diversity for these fungal communities was similar to temperate and arid ecosystems, averaging 90.1 operational taxonomic units (OTUs) per sample, with reads predominantly assigned to the Ascomycota phylum and with a saprotrophic lifestyle. ß-diversity was calculated as the distance-decay rate, and in contrast to α-diversity, was exceptionally high with a rate of -0.407. Soil properties (pH and P) principally regulated fungal community assembly in an analogous manner to temperate environments, with pH and phosphorus explaining 7.8 and 7.2% of community variation respectively. Surprisingly, altitude does not influence community formation, and there is limited evidence that climate (precipitation and temperature) play a role. Our results suggest that sampling should be performed over a wide geographical and environmental range in order to capture the full root-associated fungal diversity in subtropical regions. This study sheds further light on the diversity and distribution of the world's "hidden biodiversity."

Primer registro de Talaromyces udagawae relacionado con cuerpos humanos en descomposición, en suelo de la Argentina / First record of Talaromyces udagawae in soil related to decomposing human remains in Argentina

The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs.

Se describen e ilustran las características morfológicas de Talaromyces udagawae Stolk y Samson. Se aisló el estado teleomórfico de este hongo Ascomycota de suelo obtenido en la provincia de Buenos Aires (Argentina), por debajo de un cadáver humano en avanzado estado de descomposición. Las muestras de suelo fueron analizadas mediante lavado, dilución seriada y cámaras húmedas, técnicas ampliamente usadas para el estudio de hongos de suelo. T. udagawae formó colonias muy restringidas de color amarillo brillante en diferentes medios de cultivo, con ascos con 8 ascosporas. Las ascosporas eran elipsoidales y ornamentadas. No fue hallado el estado anamórfico. La especie también fue identificada mediante técnicas moleculares. El presente registro es el primero de la especie en la Argentina y el único que la postula como herramienta para identificar suelos donde ocurre una descomposición cadavérica.

First record of Talaromyces udagawae in soil related to decomposing human remains in Argentina.

The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs.

Comparison of soil microbial communities inhabiting vineyards and native sclerophyllous forests in central Chile.

Natural ecosystems provide services to agriculture such as pest control, soil nutrients, and key microbial components. These services and others in turn provide essential elements that fuel biomass productivity. Responsible agricultural management and conservation of natural habitats can enhance these ecosystem services. Vineyards are currently driving land-use changes in many Mediterranean ecosystems. These land-use changes could have important effects on the supporting ecosystems services related to the soil properties and the microbial communities associated with forests and vineyard soils. Here, we explore soil bacterial and fungal communities present in sclerophyllous forests and organic vineyards from three different wine growing areas in central Chile. We employed terminal restriction fragment length polymorphisms (T-RFLP) to describe the soil microbial communities inhabiting native forests and vineyards in central Chile. We found that the bacterial community changed between the sampled growing areas; however, the fungal community did not differ. At the local scale, our findings show that fungal communities differed between habitats because fungi species might be more sensitive to land-use change compared to bacterial species, as bacterial communities did not change between forests and vineyards. We discuss these findings based on the sensitivity of microbial communities to soil properties and land-use change. Finally, we focus our conclusions on the importance of naturally derived ecosystem services to vineyards.