Caracterización morfológica de hongos endófitos asociados a cacao nativo y su capacidad antagónica para el control de Moniliophthora Perniciosa

Abstract

This research was conducted with the objective of characterizing morphologically the endophytic fungi associated with native cocoa to assess their antagonistic ability to control Moniliophthora perniciosa. It was developed in the laboratory of Plant Pathology of Instituto de Cultivos Tropicales(ICT), located in the district of Banda Shilicayo, province and department of San Martin. For the morphological characterization was used 68 isolates of endophytic fungi from Alto Amazonas. Variables and categories were employed to determine the genetic distance with 185 markers, which was calculated using the DICE coefficient (Dice, 1945). Cluster analysis was done using the algorithm UPGMA (Unweighted Pair-Group Method Arithmetic Average usingn) using the Darwin program (Dissimilarity Analysis and Representation for Windows). To evaluate the antagonistic capacity of fungal endophytes, were carried out test for antibiosis and mycoparasitism through the production of soluble inhibitory metabolites and method of precolonizada plate respectively, for both tests was used the Completely Randomized Design (CRD). The cluster analysis was able to form eight big groups A, B, C, D, E, F, G and H corresponding to the genera of Trichoderma (T-E), Clonostachys (Cl-E), Botryosphaeria (Bo-E ) Xylaria (X-E), Pestalotiopsis (P-E), Acremonium (Acr-E), Fusarium (F-E) and Colletotrichum (Coll-E), respectively, and these at the same time are subdivided into 20 morphotypes (A1, A2, A3 , A4, B1, B2, B3, C1, C2, C3, D1, E1, F1, G1, G2, G3, G4, H1, H2 and H3). Likewise, the analysis of dispersion, was able to form four groups far between. The Trichoderma and Clonostachys genera showed a close approach; between Colletotrichum and Fusarium, and Botryosphaeria, Pestalotiopsis, Xylaria showed a slightly approach . However, the Acremonium genus was the most distant of the other genera. The isolation TE-17 proved to be a potential biocontrol in vitro, was able to inhibit (100%) the mycelial growth of M. perniciosa, followed by isolation Bo-E-107 that inhibited 45.2% compared of isolates Cl-E-61, Cl-E-119 and Coll-E-33 that had no effect on mycelial inhibition. Likewise, TE-17 proved to be the only aggressive mycoparasite (100% colonization), compared to other isolates of endophyte fungi that had no effect on mycoparasitism of M. perniciosa.

El presente trabajo de investigación se realizó con el objetivo de caracterizar morfológicamente los hongos endófitos asociados a cacao nativo para evaluar su capacidad antagónica para el control de Moniliophthora perniciosa. Se desarrolló en el Laboratorio de Fitopatología del Instituto de Cultivos Tropicales (ICT), ubicado en el distrito de la Banda de Shilicayo, provincia y departamento de San Martín. Para la caracterización morfológica se utilizó 68 aislamientos de hongos endófitos procedentes del Alto Amazonas. Se empleo variables y categorías, para determinar la distancia genética con 185 marcadores, la cual fue calculada con el coeficiente de DICE (Dice, 1945). El análisis de agrupamiento se realizó mediante el algoritmo UPGMA (Unweighted Pair-Group Method usingn Arithmetic Average) utilizando el Programa DARwin (Dissimilarity Analysis and Representation for Windows). Para evaluar la capacidad antagónica de los hongos endófitos, se realizaron pruebas de antibiosis y micoparasitismo mediante la producción de metabolitos inhibitorios solubles y el método de placa precolonizada respectivamente, para ambas pruebas se utilizó el Diseño Completamente al Azar (DCA). Con el análisis de agrupamiento, se logró formar ocho grandes grupos A, B, C, D, E, F, G y H que corresponden a los géneros: Trichoderma (T-E), Clonostachys (Cl-E), Botryosphaeria (Bo-E), Xylaria (X-E), Pestalotiopsis (P-E), Acremonium (Acr-E), Fusarium (F-E) y Colletotrichum (Coll-E); respectivamente, y estos a su vez se subdividen en 20 morfotipos, (A1, A2, A3, A4, B1, B2, B3, C1, C2, C3, D1, E1, F1, G1, G2, G3, G4, H1, H2, y H3). Así mismo, en el análisis de dispersión, se logro formar cuatro grupos distantes entre si. Los géneros Trichoderma y Clonostachys, muestran un estrecho acercamiento y ligero acercamiento entre los géneros Colletotrichum y Fusarium, y Botryosphaeria, Xylaria y Pestalotiopsis; sin embargo, el género Acremonium se encuentra muy distante a los demás géneros. El aislamiento T-E-17, resultó ser un potencial biocontrolador in vitro, logró inhibir (100%) el crecimiento micelial de M. perniciosa, seguido del aislamiento Bo-E-107 que inhibió el 45,2 % a comparación de los aislamientos Cl-E-61, Cl-E- 119 y Coll-E- 33 no tuvieron efecto en la inhibición micelial. Así mismo, T-E-17 resulto ser el único micoparásito más agresivo (100% de colonización), a comparación de los demás aislamientos de hongos endófitos que no tuvieron efecto en micoparasitar a M. perniciosa. This research was conducted with the objective of characterizing morphologically the endophytic fungi associated with native cocoa to assess their antagonistic ability to control Moniliophthora perniciosa. It was developed in the laboratory of Plant Pathology of Instituto de Cultivos Tropicales(ICT), located in the district of Banda Shilicayo, province and department of San Martin. For the morphological characterization was used 68 isolates of endophytic fungi from Alto Amazonas. Variables and categories were employed to determine the genetic distance with 185 markers, which was calculated using the DICE coefficient (Dice, 1945). Cluster analysis was done using the algorithm UPGMA (Unweighted Pair-Group Method Arithmetic Average usingn) using the Darwin program (Dissimilarity Analysis and Representation for Windows). To evaluate the antagonistic capacity of fungal endophytes, were carried out test for antibiosis and mycoparasitism through the production of soluble inhibitory metabolites and method of precolonizada plate respectively, for both tests was used the Completely Randomized Design (CRD). The cluster analysis was able to form eight big groups A, B, C, D, E, F, G and H corresponding to the genera of Trichoderma (T-E), Clonostachys (Cl-E), Botryosphaeria (Bo-E ) Xylaria (X-E), Pestalotiopsis (P-E), Acremonium (Acr-E), Fusarium (F-E) and Colletotrichum (Coll-E), respectively, and these at the same time are subdivided into 20 morphotypes (A1, A2, A3 , A4, B1, B2, B3, C1, C2, C3, D1, E1, F1, G1, G2, G3, G4, H1, H2 and H3). Likewise, the analysis of dispersion, was able to form four groups far between. The Trichoderma and Clonostachys genera showed a close approach; between Colletotrichum and Fusarium, and Botryosphaeria, Pestalotiopsis, Xylaria showed a slightly approach . However, the Acremonium genus was the most distant of the other genera. The isolation TE-17 proved to be a potential biocontrol in vitro, was able to inhibit (100%) the mycelial growth of M. perniciosa, followed by isolation Bo-E-107 that inhibited 45.2% compared of isolates Cl-E-61, Cl-E-119 and Coll-E-33 that had no effect on mycelial inhibition. Likewise, TE-17 proved to be the only aggressive mycoparasite (100% colonization), compared to other isolates of endophyte fungi that had no effect on mycoparasitism of M. perniciosa.