Actividad antifúngica de metabolitos bacterianos frente a Mycosphaerella fijiensis Morelet
Fecha
2012-06-28
Autores
Mena Méndez, Eilyn
Título de la revista
ISSN de la revista
Título del volumen
Editor
Universidad Central ´´Marta Abreu´´ de Las Villas
Resumen
Las bacterias asociadas a cultivos han sido empleadas para incrementar la nutrición de la planta y como fuentes de agentes de biocontrol, pero pocas son las investigaciones relacionadas con la interacción Musa spp.-microorganismo-microorganismo. Por ello, este trabajo tuvo como objetivo caracterizar la actividad antifúngica de metabolitos producidos por bacterias frente a Mycosphaerella fijiensis. Con este fin se obtuvieron filtrados de cultivo a partir de bacterias que inhibieron in vitro el crecimiento del patógeno y se evaluó su efecto sobre la respuesta de plantas de Musa sp. inoculadas con este hongo. Así como también, se caracterizó la actividad antifúngica de estos con respecto a la estabilidad ante variaciones de la temperatura, el pH, susceptibilidad a la desnaturalización proteica por detergentes y proteinasa K. Además, se semipurificó la fracción proteica mediante la precipitación con sulfato de amonio (70%) y diálisis con membrana de 12kDa de exclusión. Los filtrados de cultivo de las cepas, mostraron actividad antifúngica in vitro a partir de las 48 horas de incubación y tuvieron efecto sobre la respuesta de plantas inoculadas con M. fijiensis en casa de cultivo, en dependencia de la cepa bacteriana empleada y del momento de su aplicación. La actividad antifúngica se vio afectada por la temperatura, el pH, así como, en presencia de detergentes CTAB, Tritón x-100 y Tween-80 y la enzima proteinasa K en dependencia de la cepa. Estos resultados sugirieron la posible naturaleza proteica de los metabolitos con actividad antifúngica. Se comprobó que la actividad antifúngica de los filtrados de cultivo frente a Mycosphaerella fijiensis estuvo relacionada con metabolitos de naturaleza proteica presentes en su composición.
Bacteria associated to crop have been employed to increase the nutrition of plants and as sources of biocontrol agent, but a few investigations are related the interaction Musa spp.-microorganism- microorganism. For that reason, the aim of this work is to characterize the antifungal activity of metabolites produced by bacteria against Mycosphaerella fijiensis. With this objective were obtained cell-free culture filtrate from bacteria who inhibited the pathogen growth in vitro and was evaluated their effect on the Musa spp. plants response inoculated with this fungus. As well as, were characterized the antifungal activity of these with respect to thermal and pH stability, susceptibility to protein denaturing detergents and proteinase K. In addition, was half-purified protein fraction by means of ammonium sulphate precipitation to achieve 70% saturation and dialysis with membrane of 12kDa shutting out. Cell-free cultures filtrate from bacteria, showed antifungal activity in vitro from 48 hours of incubation and had effect on the Musa spp. plants response inoculated with this fungus in greenhouse, dependence of the strain bacterium employed and the moment of its application. The antifungal activity look affected by temperature, pH, as well as, in the presence of detergents CTAB, Triton x-100 and Tween-80 and enzyme proteinase K in dependency of the strain. These results suggested the possible protein nature of the metabolites with antifungal activity. In this study, was verified that the antifungal activity of cell-free cultures filtrate against Mycosphaerella fijiensis was related with metabolites of protein nature in its composition.
Bacteria associated to crop have been employed to increase the nutrition of plants and as sources of biocontrol agent, but a few investigations are related the interaction Musa spp.-microorganism- microorganism. For that reason, the aim of this work is to characterize the antifungal activity of metabolites produced by bacteria against Mycosphaerella fijiensis. With this objective were obtained cell-free culture filtrate from bacteria who inhibited the pathogen growth in vitro and was evaluated their effect on the Musa spp. plants response inoculated with this fungus. As well as, were characterized the antifungal activity of these with respect to thermal and pH stability, susceptibility to protein denaturing detergents and proteinase K. In addition, was half-purified protein fraction by means of ammonium sulphate precipitation to achieve 70% saturation and dialysis with membrane of 12kDa shutting out. Cell-free cultures filtrate from bacteria, showed antifungal activity in vitro from 48 hours of incubation and had effect on the Musa spp. plants response inoculated with this fungus in greenhouse, dependence of the strain bacterium employed and the moment of its application. The antifungal activity look affected by temperature, pH, as well as, in the presence of detergents CTAB, Triton x-100 and Tween-80 and enzyme proteinase K in dependency of the strain. These results suggested the possible protein nature of the metabolites with antifungal activity. In this study, was verified that the antifungal activity of cell-free cultures filtrate against Mycosphaerella fijiensis was related with metabolites of protein nature in its composition.
Descripción
Palabras clave
Metabolitos, Mycosphaerella Fijiensis Morelet, Hongos