Abstract Wheat is one of the most important cultivated cereals in Uruguay for human consumption; however, when harvest yields are low, wheat is usually used in ensiling for animal feeding. Ensiling is a forage preservation method that allows for storage during extended periods of time while maintaining nutritional values comparable to fresh pastures. Silage is vulnerable to contamination by spoilage molds and mycotoxins because ensilage materials are excellent substrates for fungal growth. The aim of the study was to identify the mycobiota composition and occurrence of aflatoxins and DON from wheat silage. A total of 220 samples of wheat were collected from four farms in the southwest region of Uruguay were silage practices are developed. The main fungi isolated were Fusarium (43%) and Aspergillus (36%), with Fusarium graminearum sensu lato and Aspergillus section Flavi being the most prevalent species. Aflatoxin concentrations in silo bags ranged from 6.1 to 23.3 µg/kg, whereas DON levels ranged between 3000 µg/kg and 12,400 µg/kg. When evaluating aflatoxigenic capacity, 27.5% of Aspergillus section Flavi strains produced AFB1, 5% AFB2, 10% AFG1 and 17.5% AFG2. All isolates of F. graminearum sensu lato produced DON and 15-AcDON. The results from this study contribute to the knowledge of mycobiota and mycotoxins present in wheat silage.

Fusarium circinatum Nirenberg & O’Donnell, the pitch canker fungus, has been recently reported in Uruguay affecting Pinus taeda L. seedlings. The spread of this pathogen to plantations constitute a risk to forestry production. The aim of this work was to evaluate the inhibitory effect of live bacteria and their thermostable metabolites on F. circinatum growth in vitro. Four Bacillus subtilis strains and one of Burkholderia sp. isolated as P. taeda endophytes were evaluated as biological control agents of F. circinatum. Dual cultures between live bacteria and pathogen were performed. Furthermore, bacteria metabolites obtained from liquid cultures were sterilized and added to the culture media where fungus was grown. In this study all bacteria showed an antagonist effect on the pathogen growth arresting the mycelia at one cm of the edge of the bacteria colony. Bacteria thermostable metabolites reduced over 50% fungal growth. These results demonstrates that endophytic bacteria, well adapted to live in host tissues, constitute a good alternative to control F. circinatum affecting Pinus seedlings.

La presencia de Fusarium circinatum Niremberg & O’Donnell, agente causal del cancro resinoso en pino, ha sido detectada recientemente en plántulas de Pinus taeda L. en Uruguay. La propagación de este patógeno en las plantaciones constituye un riesgo para la producción forestal. El objetivo de este trabajo fue determinar la capacidad inhibitoria de bacterias vivas y de sus metabolitos termoestables sobre el crecimiento de F. circinatum in vitro. Cuatro cepas de Bacillus subtilis y una de Burkholderia sp. aisladas como endófitas de P. taeda, fueron evaluadas como potenciales agentes de control biológico sobre F. circinatum. Para ello, se realizaron enfrentamientos directos entre las bacterias vivas y el micelio del patógeno. Por otra parte, los metabolitos bacterianos obtenidos de cultivos líquidos fueron esterilizados en autoclave y se incorporaron al medio de cultivo donde se hizo crecer el patógeno. En este estudio todas las bacterias mostraron un efecto antagónico sobre el crecimiento del patógeno, deteniéndose el avance del micelio a 1 cm del borde de la colonia bacteriana. Los metabolitos termoestables de las bacterias produjeron una disminución significativa en la tasa de crecimiento del hongo mayor al 50%. Estos resultados muestran que las bacterias que viven dentro de los tejidos sanos del hospedante son una buena alternativa para el control del patógeno F. circinatum en plántulas de Pinus.

The surface coverage of certain dry fermented sausages such as Italian salami by some species of Penicillium provides their characteristic flavor and other beneficial properties. One of them is the protective effect by means of a uniform film of white mold against undesirable microorganisms. The aim of this work was to identify and to isolate the fungal species present in mature Italian type of salami and to evaluate if it is possible to obtain some of them as starters. In addition, the effects of temperature (14 °C and 25 °C), water activity (a w) (0.90, 0.95 and 0.995) and 2.5 % sodium chloride (NaCl) on fungal growth were determined. Similarly, the proteolytic and lipolytic activity and the ability to produce toxic secondary metabolites were evaluated in order to characterize some possible starter strain. All species found belong to the genus Penicillium, including a performing starter as Penicillium nalgiovense and some potentially toxicogenic species. All the strains showed a higher growth rate at 25 °C. The production of extracellular proteases and lipases was significantly higher at 25 °C than at 14 °C with and without sodium chloride. Only Penicillium expansum produced patulin. On the other hand, Penicillium griseofulvum was the only species that produced ciclopiazonic acid but none of the strains produced penicillin. The species present on salami, Penicillium nalgiovense, Penicillium minioluteum, Penicillium brevicompactum and Penicillium puberulum were unable to produce any of the evaluated toxins. These findings suggest that some fungal isolates from the surface of salami such as P. nalgiovense are potentially useful as starters in sausage manufacture.

La cobertura de la superficie de los embutidos fermentados secos -como el salamín tipo italiano- por algunas especies de Penicillium les proporciona un sabor característico y otras propiedades beneficiosas. Una de ellas es el efecto de protección contra microorganismos indeseables, al formarse una película blanca uniforme de mohos. El objetivo de este trabajo fue aislar e identificar los hongos filamentosos encontrados en la superficie de salamines tipo italiano y evaluar la posibilidad de obtener especies para utilizarse como cultivos iniciadores. Se determinó el efecto de la temperatura, la actividad de agua y del cloruro de sodio sobre el crecimiento fúngico. La actividad proteolítica y lipolítica y la capacidad de producir metabolitos secundarios tóxicos fueron evaluadas con el fin de caracterizar algunos posibles cultivos iniciadores. Todas las cepas fúngicas aisladas e identificadas correspondieron a especies del género Penicillium, algunas benéficas, como Penicillium nalgiovense, y otras potencialmente toxicogénicas. Estas cepas tuvieron diferentes tasas de crecimiento en respuesta a las diferentes condiciones de cultivo. Todas las cepas mostraron mayor crecimiento a 25 °C. La producción de proteasas y lipasas extracelulares fue significativamente mayor a 25 °C que a 14 °C. Penicillium expansum fue la única especie que produjo patulina y Penicillium griseofulvum fue la única que produjo ácido ciclopiazónico. Ninguna de las especies produjo penicilina. Penicillium nalgiovense, Penicillium minioluteum, Penicillium brevicompactum y Penicillium puberulum no produjeron ninguna de las toxinas evaluadas. Estos resultados sugieren que algunos aislamientos fúngicos, como P. nalgiovense, son potencialmente útiles como cultivos iniciadores en la fabricación de estos productos.

As lesões na casca de Eucalyptus globulus Labill. são frequentemente observadas nas plantações da Região Centro-Oeste do Uruguai. Constituem problema para o descortiçamento na colheita e, além disso, facilita a penetraçao de fungos apodrecedores da madeira. Selecionaram-se plantações com 1, 3 e 7 anos de idade, em três localidades próximas, para serem estudadas. Quatro tipos de lesões em caule foram encontrados nas árvores, independentemente da idade destas. Numa mesma plantaçao, havia mais de um tipo de lesão. Os objetivos deste estudo foram identificar a composição da micobiota associada a cada tipo de lesão da casca, compará-la com a dos tecidos sadios e investigar a origem desses sintomas. Outro objetivo foi verificar o papel de alguns colonizadores considerados patógenos, através de inoculações experimentais. Obtiveram-se 897 isolamentos correspondentes, a 32 taxa, 681 de casca lesionada e 216 dos tecidos sadios. Tanto os tecidos lesionados quanto os sadios mostraram composição micobiota específica similar, mas diferentes na frequência de colonização. Cytospora eucalyptica Van der Westhuizen, Botryosphaeria spp., Pestalotiopsis guepinii (Desm.) Stey. e Penicillum spp. foram as espécies dominantes isoladas. Devido à não reprodução dos sintomas depois da inoculação experimental com Botryosphaeria ribis Grossenb. & Duggar e B. eucalyptorum Crous & Wingf, foi sugerido que as lesões aqui estudadas fossem originadas de condições ambientais desfavoráveis. A ocorrência de geadas fora de estação associada à inundação pode ter influenciado o desenvolvimento dessas lesões na casca.

Trees with stem bark lesions are frequently observed in Eucalyptus globulus Labill. plantations, particularly in the central west region of Uruguay. These lesions constitute a problem for trunk decortications at harvest and they also facilitate the access of fungi that could cause wood decay. Seven, three and oneyear-old plantations, located at three sites in close proximity were selected. Four types of trunk lesions were present in trees regardless the age of plantation and more than one type was found in each plantation. The aim of this study was to investigate the fungal composition associated with these lesions and compare them to healthy tissues and try to find out the origin of these symptoms. Another purpose was to elucidate the real role of the fungi considered pathogens by means of experimental inoculations. Segments from lesions and healthy tissues yielded 897 fungal isolates belonging to 32 taxa, 681 isolates from bark lesions and 216 from healthy tissues. Both healthy and symptomatic tissues showed similar fungal species composition, but with differences in frequencies of colonization. Cytospora eucalypticola Van der Westhuizen, Botryosphaeria spp., Pestalotiopsis guepinii (Desm.) Stey. and Penicillium spp. were the dominant species isolated. As symptoms were not reproduced after experimental inoculation with Botryosphaeria ribis Grossenb. & Duggar and B. eucalyptorum Crous, & M.J. Wingf, it could be suggested that these lesions were originated by unfavorable environmental conditions. The frost that occurred for several days out of season and flooding may have been involved in the development of bark lesion.

Este trabalho objetivou isolar fungos causadores da podridão-branca da madeira, a partir de basidiocarpos e de fragmentos de madeira de eucalipto coletados em várias regiões do país, bem como testar seu potencial de degradação de cepas e raízes mortas em plantios comerciais de eucalipto, após o corte raso. Para o isolamento dos fungos foi desenvolvido um meio de cultura de serragem de eucalipto-ágar. Dentre 292 isolados obtidos e submetidos ao teste de Bavendamm, 144 foram classificados como causadores de podridão-branca, capazes de produzir fenoloxidases. Dentre as nove relações C/N testadas, observou-se uma tendência de ocorrer maior degradação de cavacos naquelas iguais a 60 : 1, 200 : 1 e 300 : 1. Utilizando a relação C/N igual a 60 : 1, realizaram-se dois experimentos para avaliar a degradação de cavacos de Eucalyptus saligna por isolados fúngicos de podridão-branca. No primeiro experimento, avaliado aos 90 dias de incubação, foram selecionados sete isolados, que causaram perda de peso em cavacos superior ou igual à causada por Trametes versicolor, usado para comparação. No segundo experimento foram testados 46 isolados fúngicos. Dentre os mais eficientes estavam os sete isolados selecionados no primeiro teste, além de outros quatro isolados. Baseado na análise de DNA, seis isolados foram identificados, sendo três pertencentes à espécie Pycnoporus sanguineus, um ao gênero Peniophora sp., um ao gênero Pestalotiopsis sp. e um ao gênero Ganoderma sp.

The aim of this work was to isolate native wood white-rot fungi from fungal fruit-bodies and eucalyptus wood fragments from different regions of Brazil and to test their potential for degrading dead stumps and roots in Eucalyptus plantings after harvest. Fungi isolates were obtained in a culture medium composed by Eucalyptus sawdust and agar. Among 292 isolates submitted to the Banvedamm test, 144 were classified as phenoloxidases producing isolates. Among nine C/N ratios tested, it was observed a tendency of occurring larger chip decay in the C/N ratios equal to 60 : 1, 200 : 1 and 300 : 1. Two decay assays were performed in wood chips of Eucalyptus saligna using the C/N ratio 60 : 1 in order to verify which isolates were able to cause larger reduction of dry matter. In the first assay, which was evaluated at 90 days of incubation, seven isolates that stood out in relation to Trametes versicolor were selected. The second assay evaluated the capacity of 46 isolates in promoting decay. The isolates selected in the first assay were among the 11 most efficient in the second assay. Based on DNA analysis, six isolates were identified as Pycnoporus sanguineus (3 isolates), Peniophora sp., Pestalotiopsis sp. e Ganoderma sp.

Cytospora eucalypticola tem sido, freqüentemente, associado a lesões de pequenos ramos e cancros de caules e como endofíto de Eucalyptus globulus e E. grandis no Uruguai. Discos de micélio de dois isolados do C. eucalypticola obtidos de colônias crescendo ativamente foram inoculados superficialmente e em caules de E. globulus e E. grandis feridos experimentalmente. Não se observou exsudação de goma, descoloraçao, necrose, nem lesões dez meses depois nos controles. O tecido de calo foi formado, parcialmente ou totalmente fechando as feridas. A capacidade de penetrar tecidos saudáveis e a incapacidade de produzir lesões evidenciou que a presença de C. eucalypticola em cancro do caule pode resultar em uma expansão saprofítica do micélio em tecidos enfraquecidos. O cancro provavelmente foi produzido por algum tipo de estresse abiotico

Cytospora eucalypticola has been frequently associated with twig and stem cankers and as endophyte of Eucalyptus globulus and E. grandis in Uruguay. Mycelium discs of two C. eucalypticola isolates obtained from actively growing colonies were inoculated, both superficially and on experimentally wounded stems of E. globulus and E. grandis. No inoculated and control plants have shown any discoloration, gumosis or necrosis nor did they display lesions ten months after inoculation. Callus tissue was formed, partially or wholly occluding the wounds. The ability to penetrate healthy tissues and the inability to produce lesions evidenced that the presence of C. eucalypticola in twig and stem cankers could result from saprotrophic expansion of the endophytic mycelium in dying tissues, cankers probably being produced by different environmental stress conditions.

Inonotus splitbergeri é relatado pela primeira vez o Uruguay causando podridáo-do-lenho de Eucalyptus globulus. Durante as tempestades ocorre o tombamento de árvores, mesmo daquelas totalmente enfolhadas.