Molecular Insights into the Defense of Dioscorea opposita Cultivar Tiegun Callus Against Pathogenic and Endophytic Fungal Infection Through Transcriptome Analysis.

Dioscorea opposita cultivar Tiegun is an economically important crop with high nutritional and medicinal value. Plants can activate complex and diverse defense mechanisms after infection by pathogenic fungi. Moreover, endophytic fungi can also trigger the plant immune system to resist pathogen invasion. However, the study of the effects of endophytic fungi on plant infection lags far behind that of pathogenic fungi, and the underlying mechanism is not fully understood. Here, the black spot pathogen Alternaria alternata and the endophytic fungus Penicillium halotolerans of Tiegun were identified and used to infect calli. The results showed that A. alternata could cause more severe membrane lipid peroxidation, whereas P. halotolerans could rapidly increase the activity of the plant antioxidant enzymes superoxide dismutase, peroxidase, and catalase; thus, the degree of damage to the callus caused by P. halotolerans was weaker than that caused by A. alternata. RNA sequencing analysis revealed that various plant defense pathways, such as phenylpropanoid biosynthesis, flavonoid biosynthesis, plant hormone signal transduction, and the mitogen-activated protein kinase signaling pathway, play important roles in triggering the plant immune response during fungal infection. Furthermore, the tryptophan metabolism, betalain biosynthesis, fatty acid degradation, flavonoid biosynthesis, tyrosine metabolism, and isoquinoline alkaloid biosynthesis pathways may accelerate the infection of pathogenic fungi, and the ribosome biogenesis pathway in eukaryotes may retard the damage caused by endophytic fungi. This study lays a foundation for exploring the infection mechanism of yam pathogens and endophytic fungi and provides insight for effective fungal disease control in agriculture.

WSC1 Regulates the Growth, Development, Patulin Production, and Pathogenicity of Penicillium expansum Infecting Pear Fruits.

In this study, the role of WSC1 in the infection of pear fruit by Penicillium expansum was investigated. The WSC1 gene was knocked out and complemented by Agrobacterium-mediated homologous recombination technology. Then, the changes in growth, development, and pathogenic processes of the knockout mutant and the complement mutant were analyzed. The results indicated that deletion of WSC1 slowed the growth rate, reduced the mycelial and spore yield, and reduced the ability to produce toxins and pathogenicity of P. expansum in pear fruits. At the same time, the deletion of WSC1 reduced the tolerance of P. expansum to cell wall stress factors, enhanced antioxidant capacity, decreased hypertonic sensitivity, decreased salt stress resistance, and was more sensitive to most metal ions. Our results confirmed that WSC1 plays an important role in maintaining cell wall integrity and responding to stress, toxin production, and the pathogenicity of P. expansum.

Hongos anamorfos biodegradan los libros del Área Histórica de la Universidad Central del Ecuador (UCE) / Anamorphous fungi biodegrade the books of the Historical Area from the Central University of Ecuador (CUE)

Determinamos los géneros de hongos anamorfos que contaminan los libros del área de cuarentena y limpieza, dentro del Área Histórica de la Universidad Central del Ecuador (UCE). Realizamos un hisopado aleatorio a una muestra representativa de 50 de estos libros de acuerdo a una Tabla militarizada estándar. También hisopamos como muestra preferencial a 21 libros gravemente contaminados con hongos. Los hisopados tuvieron una superficie de 5x5 cm, friccionando en la pasta, el borde y el interior de estos libros. Las 213 muestras tomadas fueron inoculadas en medio de cultivo Agar Malta. Los medios fueron incubados a una temperatura de 28°C durante 7 días. Realizamos observaciones por microscopía a 40 y 100x además de usar literatura especializada para la identificación hasta el nivel de género de hongos anamorfos. Los géneros más abundantes en este estudio fueron Penicillium (80,2%) y Mucor (8,1%). (AU)

We determined the genera of anamorphic fungi that contaminate the books in the quarantine and cleaning area, within the Historical Area of the Central University of Ecuador (CUE). We performed a random swab on a representative sample of 50 of these books according to a standard militarized Table. We also swabbed as a preferential sample 21 books seriously contaminated with fungi. The swabs had a surface area of 5x5 cm, rubbing on the paste, the edge and the interior of these books. The 213 samples taken were inoculated in Agar Malta culture medium. The media were incubated at a temperature of 28° C for 7 days. We made observations by microscopy at 40 and 100x in addition to using specialized literature for the identification down to the genus level of anamorphic fungi. The most abundant genus in this study were Penicillium(80,2%) and Mucor(8,1%). (AU)

Levedura antagonista no controle de fungos filamentosos deteriorantes de alimentos / Antagonistic yeast against deteriorating mold of food

Este trabalho avaliou o efeito antifúngico in vitro de toxina killer de Hansenula wingei contra Aspergillus ochraceus e Penicillium expansum deteriorantes de alimentos. O extrato livre de células-ELC contendo a toxina killer (obtido a partir do cultivo da levedura em Caldo MPL a 25ºC/96 horas) foi submetido ao ensaio antifúngico por meio de análise microscópica, determinando-se a porcentagem de germinação conidial e o desenvolvimento de hifas dos fungos testados. H. wingei inibiu a germinação conidial de A. ochraceus e P. expansum em 98,91% e 96,49%, respectivamente, bem como a inibição do desenvolvimento micelial de ambos os fungos foi maior que 78%. O composto antifúngico mostrou-se estável ao tratamento térmico de 90ºC/30 min., indicando a possibilidade de aplicação no biocontrole in situ de frutos pós-colheita.

La sensibilización a hongos ambientales y su relación con enfermedades atópicas en escolares / The sensitivity to environmental fungus and its relation to atopic diseases present in school children

Las enfermedades alérgicas y el asma, sobre todo en la población infantil, son afecciones muy frecuentes en todo el mundo y en Cuba. Con el objetivo de determinar la frecuencia de sensibilización a hongos ambientales y su relación con enfermedades atópicas, se realizó un estudio analítico transversal en 100 escolares de 6 a 7 años de una escuela primaria de San Antonio de los Baños, provincia La Habana, en el período comprendido entre septiembre de 2006 y marzo de 2007. El 27 por ciento de la muestra seleccionada padecía de asma, el 40 por ciento de rinitis alérgica y el 26 por ciento de dermatitis atópica. La sensibilización micótica más frecuente resultó Penicillium, para un 50 por ciento de la muestra. No hubo una asociación estadísticamente significativa entre reactividad cutánea a hongos ambientales y la presencia de enfermedades atópicas; tampoco fue significativa su asociación con la enfermedad alérgica respiratoria ni dermatitis atópica. Se concluye que la mayor sensibilización a hongos anemófilos se apreció al Penicillium, aunque sin asociación con la presencia de enfermedades atópicas

The allergic diseases and the asthma, mainly in children, are very frequent affections at world level and in Cuba. The objective of present paper was to determine the sensitization frequency to environmental fungi and its relation to atopic diseases, thus, a cross-sectional and analytical study was conducted in 100 school children aged 6 to 7 from a primary school of San Antonio de los Ba±os, La Habana province, from September 2006 to March, 2007. The 27 percent of the selected sample suffered from asthma, the 40 percent of allergic rhinitis, and the 26 percent had Penicillium for the 50 percent of sample. There was not a significant statistic association between the cutaneous reactivity to environmental fungi and the presence of atopic diseases and its association with the respiratory allergic disease as well as the atopic dermatitis was not significant. We conclude that the greater sensitization to anemophilic fungi was to Penicillium, although without an association with the presence of atopic diseases

Study of the interactions between Penicillium oxalicum Currie & Thom and Alternaria alternata (Fr. ) Keissler

The aim of this research was the analysis of the possible antagonistic effect of Penicillium oxalicum over the pathogen rice fungus A. alternata under different conditions of temperature, water activity and culture media. The macroscopic study of the dual growth revealed that according to the Index of Dominance P. oxalicum was more competitive that A. alternata at 25ºC whereas at 15ºC was this species. Microscopic analysis showed that P. oxalicum was a mycoparasite of A. alternata at all conditions tested. The antagonist penetrated into A. alternata and disintegrated its conidiophores and conidia. The results suggests that P. oxalicum may be a possible biological control agent of the rice pathogens in a future.

Hongos celulolíticos asociados al rastrojo de trigo y su relación con algunas variables ambientales / Cellulolytic fungi associated to stubble of wheat and its relationship with some environmental variables

Se cuantificó e identificó la población de hongos celulolíticos, asociados al rastrojo de trigo, relacionándolos con algunas variables ambientales. En parcelas bajo siembra directa del grano, incluidas en un diseño en bloques aleatorizados con tres repeticiones, los restos de cosecha de trigo obtenidos de 1 m(2) se cortaron y distribuyeron en bolsas de malla. Mensualmente se procedió a determinar la pérdida de peso del rastrojo y a registrar las variables agroclimáticas. Se cuantificó e identificó la población fúngica celulolítica por el método de dilución en placas en medio selectivo. Por análisis de regresión múltiple, se examinó la relación entre las variables ambientales y el peso del rastrojo con la micota celulolítica (r(2)= 0,95). Por análisis stepwise, la temperatura edáfica, la variación de la humedad relativa y las precipitaciones fueron las variables más explicativas. Los hongos celulolíticos más aislados fueron especies de penicillium y fusarium. En este último género se destaca la presencia de f. solani y f. graminearum, potenciales patógenos de cultivos vegetales

Biodeterioro de materiales plásticos por microhongos / Biodegradation of plastic compounds by microfungi

Mediante la selección de 8 compuestos plásticos utilizados en el mercado, adquiridos a la firma Aldrich Química SRL (Alemania), se valoró su capacidad de ser asimiladas como única fuente de carbono in vitro, por 2 grupos de microhongos pertenecientes a los asco-deuteromycetes. Estos compuestos fueron: poliestireno, polivinilacetato, poliacrilonitrito, policaprolactona, polimetacrilato de metilo, polivinilcloruro, acetato de celulosa y polietileno. Solo la policaprolactona y el polivinilacetato fueron utilizados por los 2 grupos de hongos en estudio, en especial por cepas de aspergillus, chaetomiun, cladosporium, fusarium, penicillium y scopulariopsis. La policaprolactona fue el polímero más utilizado entre ph 6.5 a 8. Las diferentes especies pertenecientes a los géneros aspergillus y fusarium, presentaron la mayor actividad en la utilización de estos compusetos

Aspectos micromorfológicos do Penicillium marneffei em vida saprofítica. Produçäo de clamidoconídos com septaçöes transversas / Micromorphologic aspects of Penicillium marneffei in saprophytic life. Chlamydoconidia production with transversal septations

Examinando, ao microscópico óptico comum, Penicillium marneffei Segretain, 1959, amostra isolada de um paciente francês com AIDS, apó seu retorno da Indonésia (Ancelle e dols), cultivada em ágar-Sabouraud a 37-C, após 14 dias de incubaçäo, verificamos ao lado de formas de frutificaçäo caracteristicas do gênero Penicillium, clamidoconídios de parede espessa, com septaçöes transversais formando dois a três elementos fúngicos. Estes foram semelhantes aos observados por Drouhet e cols. quando estudaram à microscopia eletrônica as formas parasitárias desse microrganismo no hamster dourado inoculado com a referida amostra. Justifica-se este trabalho para mostrar que, tanto em vida parasitária como em vida saprofítica os clamidoconídios com parede espessa e septos transversais ocorrem com freqüência, näo havendo brotamento como em casos de histoplasmose clássica, em sua forma parasitária. Graças a este tipo de reproduçäo, podemos separar a histoplasmose da peniciliose pelo Penicillium marneffei com a qual as duas infecçöes podem se confundir ao exame histopatológico. Na histoplasmose, os fungos näo se dividem por fissäo binária