Actividad antifúngica contra botrytis cinerea de hongo endófito aislado desde planta endémica de Chile

Los hongos endófitos son organismos capaces de vivir dentro de las plantas sin causar síntomas de enfermedad, otorgándoles beneficios adaptativos, incluyendo defensa contra patógenos. Se ha descrito que estos hongos son capaces de secretar diversos metabolitos antifúngicos. Botrytis cinerea es un hongo fitopatógeno que afecta a más de 250 cultivos de importancia agrícola y ornamental, causando la enfermedad denominada “pudrición gris" provocando grandes pérdidas económicas alrededor del mundo. El método de control mayormente utilizado es el control por medio de aplicación de fungicidas, pero la selección de cepas resistentes y la preocupación por el cuidado del medio ambiente, han llevado al desarrollo de métodos alternativos para el control de la enfermedad. El objetivo de este trabajo fue evaluar la capacidad antifúngica del endófito Alternaria sp. aislado de la planta endémica Lithraea caustica. Para esto, se realizaron ensayos de confrontación y se comprobó el efecto biocontrolador del endófito sobre B. cinerea. Luego se obtuvo un extracto desde el endófito y se evaluó la actividad antifúngica in- vitro sobre el crecimiento de B. cinerea, mostrando que el extracto obtenido tiene actividad antifúngica con un IC50 de 102,4 ppm. Los compuestos presentes en el extracto fueron separados por cromatografía, visualizándose doce compuestos, de los cuales cinco presentaron actividad antifúngica evaluada mediante bioautografía. Finalmente, se determinó que los metabolitos antifúngicos corresponden a compuestos fenólicos. La identificación de hongos endófitos capaces de secretar compuestos antifúngicos puede ayudar en el desarrollo de nuevas alternativas al uso de fungicidas convencionales para el control de la pudrición grisFil: Vidal, Araceli. Universidad de Santiago de ChileFil: Cotoras, Milena. Universidad de Santiago de ChileFil: Mendoza Leonora. Universidad de Santiago de Chil

Colonización de lolium perenne y polypogon australis por hondos endófitos obtenidos de poáceas provenientes de un relave minero de Puerto Cristal, Chile

Los hongos endófitos son un grupo polifilético de organismos que poseen la capacidad de colonizar tejidos vegetales sin causar síntomas aparentes de enfermedad y se ha demostrado que mejoran el crecimiento de las plantas sometidas a condiciones desfavorables ya sea por factores bióticos como abióticos. En nuestro laboratorio se aisló y cultivó exitosamente tres hongos endófitos provenientes de las plantas identificadas como Poa stuckertii y P. pratensis. Estas plantas se desarrollan espontáneamente en un relave de una empresa de extracción y refinamiento de minerales de Pb y Zn. Para identificar los hongos endófitos, estos fueron cultivados para visualizar la morfología de las hifas aéreas. Además, se realizaron extracciones de DNA para amplificar la región que codifica para el RNA ribosomal utilizando los marcadores fúngicos ITS1 e ITS4. Al secuenciar los productos de amplificación y realizar un dendrograma con los resultados con mayor puntaje en BLAST, se lograron identificar los hongos endófitos hasta el nivel de género, los cuales corresponden a Microdochium sp., Sarocladium sp. y Bjerkandera sp. Pensando en una proyección biotecnológica en el uso de estos hongos en fitorremediación bioasistida, se inocularon plantas de Lolium perenne y Polypogon australis, lográndose la colonización exitosa con el hongo Microdochium sp. en ambas plantas. La colonización se evaluó utilizando la amplificación los marcadores moleculares ITS y a través del cultivo de tejidos vegetales inoculadosFil: Parada, Rodolfo. Universidad de Santiago de ChileFil: Barros, Daniel. Universidad de Santiago de ChileFil: Cotoras, Milena. Universidad de Santiago de ChileFil: Ortiz, Claudia. Universidad de Santiago de Chil

Endophytic Fungi Isolated from Plants Growing in Central Andean Precordillera of Chile with Antifungal Activity against Botrytis cinerea

Botrytis cinerea is an important phytopathogenic fungus affecting the fruit production around the world. This fungus is controlled mainly by using synthetic fungicides, but many resistant isolates have been selected by the indiscriminate use of fungicides. Endophytic fungi or secondary metabolites obtained from them become an alternative method of control for this fungus. The aim of this work was to identify endophytic fungi with antifungal activity against the plant pathogenic fungus B. cinerea isolated from plants from Central Andean Precordillera of Chile. Three endophytic fungi (Ac1, Lc1 and Ec1) with antifungal activity against B. cinerea were isolated from native and endemic plants growing in Central Andean Precordillera of Chile. The isolates Lc1 (isolated from Lithraea caustica) and Ac1 (isolated from Acacia caven) were identified as Alternaria spp. and the isolate Ec1 (isolated from Echinopsis chiloensis) was identified as Aureobasidium spp. The isolated endophytic fungi would inhibit B. cinerea through the secretion of diffusible and volatile compounds affecting the mycelial growth, conidia germination and interestingly, it was also shown that the volatile compounds produced by the three isolated endophytic fungi suppressed the sporulation of B. cinerea

In Vitro Antifungal Activity of the Diterpenoid 7α-Hydroxy- 8(17)-labden-15-oic Acid and Its Derivatives against Botrytis cinerea

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Endophytic Fungi Isolated from Baccharis linearis and Echinopsis chiloensis with Antifungal Activity against Botrytis cinerea

Botrytis cinerea is one of the most important phytopathogens in agriculture worldwide, infecting economically important crops. The main control of this fungus is by synthetic fungicides, causing the selection of resistant isolates. Compounds produced by endophytic fungi have been shown to have antifungal activity against this pathogen and can be used as an alternative to synthetic fungicides. The aim of this work was to isolate endophytic fungi from Chilean foothills in the Metropolitan Region. Ten fungi were isolated from Echinopsis chiloensis and Baccharis linearis, however, only two isolates inhibited the mycelial growth of B. cinerea by antibiosis and were identified as Epicoccum sp. and Pleosporales sp. Extracts at 200 mg L−1 from Epicoccum sp. and Pleosporales sp. showed antifungal activity against B. cinerea of 54.6 and 44.6% respectively. Active compounds in the Epicoccum sp. extracts were mainly alkaloids and phenolic compounds; meanwhile, in the Pleosporales sp. extracts, terpenes and/or saponins were responsible for the antifungal activity

In Vitro and in Vivo Evaluation of the Antioxidant and Prooxidant Activity of Phenolic Compounds Obtained from Grape (Vitis vinifera) Pomace

The antioxidant and/or prooxidant ability of extracts obtained from wine waste were analyzed using in vitro and in vivo assays. Cyclic voltammetry was used as the in vitro assay to determine the antioxidant and/or prooxidant properties and, the in vivo effect on mycelial growth of the fungus Botrytis cinerea was evaluated. In addition, the prooxidant activity was evaluated by intracellular oxidation of compound 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) in B. cinerea. The extracts used in this study were obtained from grape pomace of Cabernet Sauvignon, Carménère and Syrah varieties from the Misiones de Rengo Vineyard by simple extraction, using methanol/HCl 1% (v/v), ethanol 70% (v/v), or Soxhlet extraction. According to the results obtained, gallic acid was the most represented phenolic compound independent of grape variety and extraction method. In addition, vanillic acid; protocatechuic acid, syringic acid, quercetin and kaempferol were found in the extracts. From this study it was possible concluded that, depending of the method of extraction of the grape residues and the grape variety (Cabernet Sauvignon, Carménère and Syrah), the extracts showed antioxidant and/or prooxidant activity. However, no correlation can be established between the anodic oxidation potentials of the extracts and their effect on the fungus B. cinerea

Fungitoxicity against Botrytis cinerea of a Flavonoid Isolated from Pseudognaphalium robustum

The fungotoxicity against Botrytis cinerea of a flavonoid isolated from Pseudognaphalium robustum was analyzed. Two absorption column chromatographies and one semipreparative thin layer chromatography were used to purify the active flavonoid. It was determined, by 1H-NMR spectroscopy and co-elution with standards in HPLC, that this compound was 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A). To determine the fungitoxicity of the purified compound, the effect on in vitro mycelial growth and conidial germination was studied. The compound concentration that reduced mycelial growth by 50% was 45.5 mg/mL. This compound also partially affected conidial germination of B. cinerea, reduced oxygen consumption by germinating conidia and affected the integrity of plasma membrane. Finally, using cyclic voltammetry, it was shown that the purified flavone had a pro-oxidant effect