Comparación del efecto antifúngico de Clonostachys spp. y Chaetomium spp. sobre Botrytis cinerea : caracterización de las moléculas producidas por el mejor biocontrolador
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Fecha
2015
Profesor/a Guía
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Botrytis cinerea es un hongo fitopatógeno que infecta una amplia variedad de frutas
y hortalizas, causando la pudrición gris. Uno de los blancos de este fitopatógeno es la uva
de mesa de exportación, provocando pérdidas económicas importantes para Chile.
Actualmente se utilizan fungicidas químicos para controlar la infección provocada por
Botrytis, sin embargo, se ha observado la aparición de cepas resistentes y efectos
secundarios. Una alternativa al uso de fungicidas químicos son los controladores
biológicos, pero a nivel comercial sólo Trichoderma spp. y Bacillus subtilis, han sido
utilizados en precosecha. En nuestro laboratorio se aisló una cepa de Clonostachys rosea
(RP1505) y una cepa de Chaetomium globosum (RP2808) capaces de controlar a Botrytis
en condiciones de poscosecha de uva de mesa. Según lo reportado en la literatura, C. rosea
es mejor biocontrolador de B. cinerea que C. globosum, pero estudios con las cepas de
nuestro laboratorio indican lo contrario. Con el objeto de comprender mejor este fenómeno
nos planteamos la siguiente hipótesis: La cepa RP2808 es mejor biocontrolador de B.
cinerea que la cepa RP1505, ya que produce una mayor diversidad de metabolitos
difusibles y termoestables. Se establecieron las mejores condiciones de cultivo de la cepa
RP2808 y RP1505 para la producción de metabolitos termoestables con actividad
biocontroladora sobre B. cinerea. Utilizando solventes de distinta polaridad, se aislaron los
metabolitos contenidos en los extractos con mayor actividad antifúngica de cada cepa y se
determinó que la cepa RP2808 produce metabolitos polares y apoares con actividad sobre
el crecimiento y la germinación de B. cinerea. En cambio, la cepa RP1505 solamente
produce metabolitos polares con actividad antifúngica contra B. cinerea. Mediante análisis
de HPLC-MS se identificaron 2 posibles moléculas producidas por RP2808 en medio
sólido, que presentan en su estructura un grupo fenilpirrol, descrito en otras moldculas con
actividad botricida, por lo que serian responsables del efecto antifúngico.
Botrytis cinerea is a phytopathogen fungus that infects a wide variety of fruits and vegetables, causing the gray mold disease. One target of this plant pathogen is the export table grapes, causing significant economic losses to Chile. Currently, chemical fungicides are used to control infection by Botrytis, however, there has been the emergence of resistant strains and side effects. An alternative to the use of chemical fungicides are biological control agents, but commercially only Trichoderma spp. and Bacillus subtilis have been used at preharvest. In our laboratory it was isolated a strain of Clonostachys rosea (RP1505) and a strain of Chaetomium globosum (RP2808) able to control Botrytis in postharvest conditions of table grapes. As reported in the literature, C. rosea is a better biocontrol agent of B. cinerea than C. globosum, but studies from our laboratory strains indicate otherwise. In order to better understand this phenomenon, we propose the following hypothesis: The RP2808 is better biocontrol agent of B. cinerea than strain RP1505, because it produces a greater diversity of diffusible and thermostable metabolites. The best conditions for growing of the strain RP2808 and RP1505 and for the production of thermostable metabolites to B. cinerea biocontrol, were established. Using solvents of different polarities, the metabolites contained in the extracts with increased antifungal activity of each strain were isolated and was determined that the RP2808 strain produces polar and nonpolar metabolites with activity on growth and germination of B. cinerea. In contrast, the strain RP1505 only produces polar metabolites with antifungal activity against B. cinerea. Using HPLC-MS analysis, two possible molecules produced by RP2808 on solid medium, responsible for the antifungal activity, which has in their structure a phenylpyrrole group, as such other molecules described with botricide activity.
Botrytis cinerea is a phytopathogen fungus that infects a wide variety of fruits and vegetables, causing the gray mold disease. One target of this plant pathogen is the export table grapes, causing significant economic losses to Chile. Currently, chemical fungicides are used to control infection by Botrytis, however, there has been the emergence of resistant strains and side effects. An alternative to the use of chemical fungicides are biological control agents, but commercially only Trichoderma spp. and Bacillus subtilis have been used at preharvest. In our laboratory it was isolated a strain of Clonostachys rosea (RP1505) and a strain of Chaetomium globosum (RP2808) able to control Botrytis in postharvest conditions of table grapes. As reported in the literature, C. rosea is a better biocontrol agent of B. cinerea than C. globosum, but studies from our laboratory strains indicate otherwise. In order to better understand this phenomenon, we propose the following hypothesis: The RP2808 is better biocontrol agent of B. cinerea than strain RP1505, because it produces a greater diversity of diffusible and thermostable metabolites. The best conditions for growing of the strain RP2808 and RP1505 and for the production of thermostable metabolites to B. cinerea biocontrol, were established. Using solvents of different polarities, the metabolites contained in the extracts with increased antifungal activity of each strain were isolated and was determined that the RP2808 strain produces polar and nonpolar metabolites with activity on growth and germination of B. cinerea. In contrast, the strain RP1505 only produces polar metabolites with antifungal activity against B. cinerea. Using HPLC-MS analysis, two possible molecules produced by RP2808 on solid medium, responsible for the antifungal activity, which has in their structure a phenylpyrrole group, as such other molecules described with botricide activity.
Notas
Tesis (Bioquímico, Magíster en Bioquímica)
Esta tesis se realizó en el Laboratorio de Bioquímica de la Facultad de Ciencias Biológicas de la Universidad Andrés Bello y fue financiada por el proyecto FONDEF IDEA en 2 etapas ID 14I10192.
Esta tesis se realizó en el Laboratorio de Bioquímica de la Facultad de Ciencias Biológicas de la Universidad Andrés Bello y fue financiada por el proyecto FONDEF IDEA en 2 etapas ID 14I10192.
Palabras clave
Hongos Fitopatógenos, Uvas, Enfermedades por Hongos, Control Biológico, Fungicidas