Endophytic Trichoderma strains increase soya bean growth and promote charcoal rot control

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goid., is one of the world's most serious diseases because it reduces yield and seed quality. Nowadays, biological control is an environment-friendly option for controlling plant diseases. The goals of this study were to (i) test eight endophytic Trichoderma spp. strains as biocontrol agents against M. phaseolina and (ii) further investigate two selected strains showing good behaviour against the pathogen. Pathogen-antagonist interactions were studied in dual culture, and the morphological alterations of M. phaseolina mycelia in the interaction zone were examined by light microscopy. Trichoderma strains were applied to soya bean seeds by a seed coating technique. Their bioprotective effects were assessed by in vitro and in vivo assays to evaluate radicle length, the germination percentage and the presence of typical charcoal rot symptoms in seedlings. Two Trichoderma strains were selected and they were molecularly identified as T. harzianum species complex. Their antagonistic ability against M. phaseolina was evaluated under different water availability conditions. The mechanisms used by these two endophytic strains against the pathogen were evaluated by cryo-scanning electron microscopy. The results showed that all eight Trichoderma strains successfully performed biocontrol activity against M. phaseolina by reducing colony growth and causing morphological alterations in the mycelia of M. phaseolina. All endophytes improved seed germination and radicle length, and reduced typical symptoms and disease progression on seedlings. Water availability in the medium impacted on fungal growth. At 0.995 ɑw, all the fungi grew more and faster. At 0.95 ɑw M. phaseolina grew more than the Trichoderma strains, while the pathogen grew slightly more at 0.98 ɑw than the Trichoderma strains. However, both selected Trichoderma strains grew larger and faster than the pathogen at 0.995 ɑw. The mechanisms involved in pathogen control revealed by the light and cryo-scanning microscopy studies included competition for nutrients or space and direct mycoparasitism. All the endophytic Trichoderma strains were antagonistic against M. phaseolina, however our study allowed us to select two Trichoderma strains with good potential to be included for charcoal rot management.Fil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; ArgentinaFil: Simon, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Santamarina, María Pilar. Universidad Politécnica de Valencia; EspañaFil: Roselló Caselles, Josefa. Universidad Politécnica de Valencia; EspañaFil: Consolo, Verónica Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas. Centro de Estudios de Biodiversidad y Biotecnología; ArgentinaFil: Perello, Analia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentin

In Vitro Antagonistic Activity of <i>Trichoderma harzianum</i> against <i>Fusarium sudanense</i> Causing Seedling Blight and Seed Rot on Wheat

Fusarium sudanense is a novel fungus recently isolated from asymptomatic samples of wheat grains in Argentina. The fungus caused symptoms of seedling blight and seed rot on wheat after artificial inoculations. It is known that the production of mycotoxins by pathogens belonging to the Fusarium genus is harmful to human and animal health. Moreover, the warm and humid conditions that are favorable for growth and mycotoxin production of these species put the Argentinian wheat production area at a high risk of mycotoxin contamination with this novel pathogen. The aim of this work was to evaluate the antagonistic effect of Trichoderma harzianum against F. sudanense under in vitro tests at different environmental conditions. Fungi were screened in dual culture at different water activities (αw) (0.995, 0.98, 0.95, and 0.90) and temperatures (25 and 15 °C). The growth rate of the fungi, interaction types, and dominance index were evaluated. Also, the interaction between T. harzianum and F. sudanense was examined by light and cryo-scanning microscopy. T. harzianum suppressed the growth of F. sudanense at 0.995, 0.98, and 0.95 αw at 25 °C and 0.995 and 0.98 αw at 15 °C. Macroscopic study revealed different interaction types between F. sudanense and T. harzianum on dual culture. Dominance on contact where the colonies of T. harzianum overgrew the pathogen was the most common interaction type determined. The competitive capacity of T. harzianum was diminished by decreasing the temperature and αw. At 0.95 αw and 15 °C, both fungi grew slowly, and interaction type "A" was assigned. Microscopic analysis from the interaction zone of dual cultures revealed an attachment of T. harzianum to the F. sudanense hyphae, penetration with or without formation of appressorium-like structures, coiling, plasmolysis, and a veil formation. According to our results, T. harzianum demonstrated capability to antagonize F. sudanense and could be a promising biocontrol agent.Centro de Investigación y Desarrollo en Fermentaciones Industriale

Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat

An endophytic fungus isolated from healthy wheat seeds cultivar Klein Yarará in Buenos Aires Province, Argentina, was initially identified as belonging to the Fusarium fujikuroi species complex based on morphological and cultural characteristics. The fungus role in pathogenicity was investigated by artificial inoculation of wheat seeds. Symptoms evaluated 7 and 14 days after inoculation showed that the fungus was pathogenic on seed and seedlings causing symptoms as seed decay, seedling blight and seed rot. The fungus was re-isolated to fulfill Koch’s Postulates and was identified as F. sudanense (strain LBEA 3100), a new species recorded in Argentina. The fungal identity was corroborated using molecular techniques by sequencing the ITS region, D1/D2 domains of the LSU gene and TEF-1 alpha region and by comparison with international databases. Ecophysiological studies of F. sudanense (LBEA 3100) performed at different water activities and temperatures showed faster growth rate at the highest water activity and 25 C. This is the first report of F. sudanense, isolated from healthy wheat seeds, causing typical symptoms of seedling blight and seed rot on wheat.Centro de Investigaciones en Fitopatologí

Endophytic Trichoderma strains increase soya bean growth and promote charcoal rot control

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goid., is one of the world’s most serious diseases because it reduces yield and seed quality. Nowadays, biological control is an environment-friendly option for controlling plant diseases. The goals of this study were to (i) test eight endophytic Trichoderma spp. strains as biocontrol agents against M. phaseolina and (ii) further investigate two selected strains showing good behaviour against the pathogen. Pathogen-antagonist interactions were studied in dual culture, and the morphological alterations of M. phaseolina mycelia in the interaction zone were examined by light microscopy. Trichoderma strains were applied to soya bean seeds by a seed coating technique. Their bioprotective effects were assessed by in vitro and in vivo assays to evaluate radicle length, the germination percentage and the presence of typical charcoal rot symptoms in seedlings. Two Trichoderma strains were selected and they were molecularly identified as T. harzianum species complex. Their antagonistic ability against M. phaseolina was evaluated under different water availability conditions. The mechanisms used by these two endophytic strains against the pathogen were evaluated by cryo-scanning electron microscopy. The results showed that all eight Trichoderma strains successfully performed biocontrol activity against M. phaseolina by reducing colony growth and causing morphological alterations in the mycelia of M. phaseolina. All endophytes improved seed germination and radicle length, and reduced typical symptoms and disease progression on seedlings. Water availability in the medium impacted on fungal growth. At 0.995 ɑw, all the fungi grew more and faster. At 0.95 ɑw M. phaseolina grew more than the Trichoderma strains, while the pathogen grew slightly more at 0.98 ɑw than the Trichoderma strains. However, both selected Trichoderma strains grew larger and faster than the pathogen at 0.995 ɑw. The mechanisms involved in pathogen control revealed by the light and cryo-scanning microscopy studies included competition for nutrients or space and direct mycoparasitism. All the endophytic Trichoderma strains were antagonistic against M. phaseolina, however our study allowed us to select two Trichoderma strains with good potential to be included for charcoal rot management.Centro de Investigaciones en Fitopatologí

Flipped classroom en el aprendizaje multidisciplinar colaborativo en diferentes Grados Universitarios

La implementación de nuevas metodologías que nos permita valorar si el estudiante ha alcanzado los conocimientos necesarios así como una serie de competencias y habilidades, es una de las prioridades docentes del proceso de convergencia en el espacio europeo de educación superior. El empleo de la clase inversa (flipped classroom) con el cambio en los roles aula/casa y profesor/estudiante consigue que el estudiante adquiera un papel protagonista en el proceso de la enseñanza, alcanzando destrezas en el aprendizaje autónomo, trabajo en equipo y empleo de las nuevas tecnologías. Al mismo tiempo, esta metodología hace posible la participación de estudiantes de distintos grados que trabajen en grupos temas relacionados con su titulación, así como la consecución de competencias básicas (que los estudiantes puedan transmitir información, ideas, problemas y soluciones a un público tanto especializado como no especializado), generales (capacidad para las relaciones interpersonales y el trabajo en equipo) y específicas. Esta experiencia piloto tiene como objetivo mejorar el proceso enseñanza-aprendizaje de los estudiantes del grado en farmacia, grado en ingeniería agroalimentaria y medio rural y grado en biotecnología, mediante la implementación de la metodología flipped classroom para potenciar el aprendizaje autónomo, desarrollo de competencias cognitivas y habilidades interpersonales de comunicación

Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat

An endophytic fungus isolated from healthy wheat seeds cultivar Klein Yarará in Buenos Aires Province, Argentina, was initially identified as belonging to the Fusarium fujikuroi species complex based on morphological and cultural characteristics. The fungus role in pathogenicity was investigated by artificial inoculation of wheat seeds. Symptoms evaluated 7 and 14 days after inoculation showed that the fungus was pathogenic on seed and seedlings causing symptoms as seed decay, seedling blight and seed rot. The fungus was re-isolated to fulfill Koch`s Postulates and was identified as F. sudanense (strain LBEA 3100), a new species recorded in Argentina. The fungal identity was corroborated using molecular techniques by sequencing the ITS region, D1/D2 domains of the LSU gene and TEF-1 alpha region and by comparison with international databases. Ecophysiological studies of F. sudanense (LBEA 3100) performed at different water activities and temperatures showed faster growth rate at the highest water activity and 25 ºC. This is the first report of F. sudanense, isolated from healthy wheat seeds, causing typical symptoms of seedling blight and seed rot on wheat.Fil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; ArgentinaFil: Siurana, María Pilar Santamarina. Universidad Politécnica de Valencia; EspañaFil: Caselles, Josefa Roselló. Universidad Politécnica de Valencia; EspañaFil: Simón, María Rosa. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Tecnología Agropecuaria y Forestal; ArgentinaFil: Perello, Analia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentin