Biocontrol de penicillium digitatum en cítricos de poscosecha mediante el uso de bacillus safensis
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Archivos
Fecha
2023
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Profesor/a Guía
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Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Penicillium digitatum es el hongo causante de la pudrición verde de los cítricos, siendo
el tipo de lesión más común en la poscosecha cuando se presentan heridas en su superficie
y/o se encuentra en un entorno con una temperatura mayor a 20° C con alta humedad
relativa. Actualmente, la prevención de esta patología se basa en el uso de tratamientos
físicos y químicos, estos últimos pudiendo ser perjudicial tanto para la fruta como para el
consumidor final si no se emplean responsablemente. Más aún, algunos aislados
nacionales de este fitopatógeno han demostrado niveles de resistencia a estos compuestos
químicos, pudiendo disminuir su eficiencia a largo plazo. Bajo este contexto, en la búsqueda
de soluciones sustentables a este problema, se logró seleccionar una bacteria capaz de
inhibir el crecimiento del hongo tanto in vitro como a través de en ensayos de infección en
fruta.
Inicialmente, este aislado bacteriano denominado UDLA501, fue sometido a pruebas de
caracterización microbiológica y bioquímica. Además, su identidad fue determinada
mediante la secuenciación del gen 16SrRNA. El aislado UDLA501 fue sometida a pruebas
de secreción de compuestos con actividad antífúngica mediante un enfoque OSMAC (One
Strain Many Compounds). En paralelo, se lograron caracterizar diferentes aislados de P.
digitatum desde fruta sintomatológica mediante la secuenciación de la región ITS.
Las pruebas de inhibición del hongo iniciaron verificando si la bacteria producía estos
compuestos antifúngicos de forma constitutiva, confirmando que solo ocurrían en presencia
del mismo hongo (por co-cultivo). Con el co-cultivo microbiano en placa, se logró obtener
una inhibición del crecimiento del hongo desde un 79,25% hasta un 91,09%. Finalmente,
se realizaron pruebas de patogenicidad en el fruto, obteniendo una reducción significativa
del crecimiento y esporulación del hongo a su concentración mínima infectiva (103 conidios
(o esporas) mL-1
). Estos resultados proponen un nuevo modelo de interacción bacteriahongo no descrita hasta la fecha, y con un gran potencial biotecnológico en el combate de
la pudrición verde en cítricos.
Penicillium digitatum is the fungus that causes citrus green rot, being the most common type of lesion in postharvest when there are wounds on its surface and/or it is in an environment with a temperature higher than 20° C with high relative humidity. Currently, the prevention of this pathology is based on the use of physical and chemical treatments, the latter being harmful to both the fruit and the final consumer if not used responsibly. Moreover, some national isolates of this phytopathogen have demonstrated levels of resistance to these chemical compounds, which may reduce their efficiency in the long term. In this context, in the search for sustainable solutions to this problem, we have selected a bacterium capable of inhibiting the growth of the fungus both in vitro and in fruit infection assays. Initially, this bacterial isolate, named UDLA501, was subjected to microbiological and biochemical characterization tests. In addition, its identity was determined by sequencing the 16SrRNA gene. The UDLA501 isolate was tested for secretion of compounds with antifungal activity using an OSMAC (One Strain Many Compounds) approach. In parallel, we have characterized different isolates of P. digitatum from symptomatological fruit by sequencing the ITS region. The fungal inhibition tests started by verifying whether the bacterium produced these antifungal compounds constitutively, confirming that they only occurred in the presence of the fungus itself (by co-culture). With the microbial co-culture on a plate, it was possible to obtain an inhibition of fungal growth from 79.25% to 91.09%. Finally, pathogenicity tests were performed on the fruit, obtaining a significant reduction in the growth and sporulation of the fungus at its minimum infective concentration (103 conidia (or spores) mL-1). These results propose a new model of bacteria-fungus interaction not described to date, and with a great biotechnological potential in the combat of green rot in citrus.
Penicillium digitatum is the fungus that causes citrus green rot, being the most common type of lesion in postharvest when there are wounds on its surface and/or it is in an environment with a temperature higher than 20° C with high relative humidity. Currently, the prevention of this pathology is based on the use of physical and chemical treatments, the latter being harmful to both the fruit and the final consumer if not used responsibly. Moreover, some national isolates of this phytopathogen have demonstrated levels of resistance to these chemical compounds, which may reduce their efficiency in the long term. In this context, in the search for sustainable solutions to this problem, we have selected a bacterium capable of inhibiting the growth of the fungus both in vitro and in fruit infection assays. Initially, this bacterial isolate, named UDLA501, was subjected to microbiological and biochemical characterization tests. In addition, its identity was determined by sequencing the 16SrRNA gene. The UDLA501 isolate was tested for secretion of compounds with antifungal activity using an OSMAC (One Strain Many Compounds) approach. In parallel, we have characterized different isolates of P. digitatum from symptomatological fruit by sequencing the ITS region. The fungal inhibition tests started by verifying whether the bacterium produced these antifungal compounds constitutively, confirming that they only occurred in the presence of the fungus itself (by co-culture). With the microbial co-culture on a plate, it was possible to obtain an inhibition of fungal growth from 79.25% to 91.09%. Finally, pathogenicity tests were performed on the fruit, obtaining a significant reduction in the growth and sporulation of the fungus at its minimum infective concentration (103 conidia (or spores) mL-1). These results propose a new model of bacteria-fungus interaction not described to date, and with a great biotechnological potential in the combat of green rot in citrus.
Notas
Memoria de título (Ingeniero en Biotecnología)