Caracterización morfológica y patogénica de Lasiodiplodia theobromae en Vaccinium corymbosum L., Trujillo, La Libertad
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Date
2021
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Universidad Nacional de Trujillo
Abstract
El objetivo del presente trabajo fue la caracterización morfológica y patogénica de un aislamiento de Lasiodiplodia theobromae obtenido de arándano variedad Ventura con muerte regresiva. De este aislamiento se obtuvo un cultivo monoconidial del cual se tomó un disco de 5mm de agar colonizado por el patógeno y se sembró en placas con medio de cultivo a base de papa dextrosa y agar con antibióticos (PDAA) diariamente se observó y midió la velocidad de crecimiento y coloración del micelio. Asimismo, se hicieron preparaciones en láminas fijas para observar al microscopio óptico la forma y color de las picnidias y conidias y se tomaron las dimensiones de largo y ancho de las mismas. Para evaluar la patogenicidad se utilizaron plantas de arándano de las variedades Biloxi y Bluecrop, de 5 meses de edad, a las cuales se le podo tres tallos por planta y en la zona de corte con una micropipeta se colocó 30 microlitros que contenían 5 conidias de L. theobromae, los síntomas se evaluaron considerando el avance descendente de la lesión necrótica a partir de la zona de corte y la colonización sistémica del patógeno en centímetros. La velocidad de crecimiento del micelio de L. theobroame fue de 9.4 mm por día, y la colonización total de las placas de Petri se dio en aproximadamente 5 días. Las picnidias fueron de forma globosa de color marrón oscuro a negro, con dimensiones promedio de 542.56 µm de largo por 441.11 µm de ancho. Las conidias maduras fueron de forma elipsoide de color marrón oscuro, bicelulares y con estriaciones en la superficie, las dimensiones en promedio fueron de 27.19 µm de largo y 11.54 µm de ancho. Las variedades Biloxi y Bluecrop presentaron 100% y 90% de incidencia, y con grado 4 de severidad que implica lesiones necróticas y colonización vascular sistémica que compromete toda la longitud de los tallos inoculados.
ABSTRACT The objective of the present work was the morphological and pathogenic characterization of an isolation of Lasiodiplodia theobromae obtained from Ventura variety blueberry with regressive death. From this isolation a monoconidial culture was obtained from which a 5mm disk of agar colonized by the pathogen was taken and sown in plates with culture medium based on potato dextrose and agar with antibiotics (PDAA) daily, the speed was observed and measured. growth and coloration of the mycelium. Likewise, preparations were made on fixed slides to observe the shape and color of pycnidia and conidia under the light microscope, and length and width dimensions were taken. To evaluate the pathogenicity, blueberry plants of the Biloxi and Bluecrop varieties were used, 5 months old, to which three stems per plant were pruned and in the cutting area with a micropipette was aditioned, 30 microliters containing 5 conidia of L. theobromae. The symptoms were evaluated considering the downward progression of the necrotic lesion from the cut zone and the systemic colonization of the pathogen in centimeters. The mycelium colored dark gray to black, growth rate was 9.4 mm per day, and the total colonization of the Petri dishes occurred in approximately 5 days. The pycnidia globose in shape colour from dark brown and black, with average dimensions of 542.56 µm long by 441.11 µm wide. The mature conidia were ellipsoid in shape, dark brown in color, bicellular and with striations on the surface, the average dimensions were 27.19 µm long and 11.54 µm wide. The Biloxi and Bluecrop varieties presented 100% and 90% incidence respectively, and grade 4 severity that implies necrotic lesions and systemic vascular colonization that compromises the entire length of the inoculated stems.
ABSTRACT The objective of the present work was the morphological and pathogenic characterization of an isolation of Lasiodiplodia theobromae obtained from Ventura variety blueberry with regressive death. From this isolation a monoconidial culture was obtained from which a 5mm disk of agar colonized by the pathogen was taken and sown in plates with culture medium based on potato dextrose and agar with antibiotics (PDAA) daily, the speed was observed and measured. growth and coloration of the mycelium. Likewise, preparations were made on fixed slides to observe the shape and color of pycnidia and conidia under the light microscope, and length and width dimensions were taken. To evaluate the pathogenicity, blueberry plants of the Biloxi and Bluecrop varieties were used, 5 months old, to which three stems per plant were pruned and in the cutting area with a micropipette was aditioned, 30 microliters containing 5 conidia of L. theobromae. The symptoms were evaluated considering the downward progression of the necrotic lesion from the cut zone and the systemic colonization of the pathogen in centimeters. The mycelium colored dark gray to black, growth rate was 9.4 mm per day, and the total colonization of the Petri dishes occurred in approximately 5 days. The pycnidia globose in shape colour from dark brown and black, with average dimensions of 542.56 µm long by 441.11 µm wide. The mature conidia were ellipsoid in shape, dark brown in color, bicellular and with striations on the surface, the average dimensions were 27.19 µm long and 11.54 µm wide. The Biloxi and Bluecrop varieties presented 100% and 90% incidence respectively, and grade 4 severity that implies necrotic lesions and systemic vascular colonization that compromises the entire length of the inoculated stems.
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Keywords
Muerte regresiva, Picnidia, Severidad, Caracterización patogénica y colonización vascular