Morphological and molecular characterization ofCladosporium tenuissimumCooke (Deuteromycotina: Hyphomycetes) on mango tree panicles: symptoms, pathogenicity and severity of the fungus.

Abstract

Morphological and molecular characterization of Cladosporium tenuissimum Cooke (Deuteromycotina: Hyphomycetes) on mango tree panicles: symptoms, pathogenicity and severity of the fungus. Abstract-Introduction. Mango producers of two important growing areas of the states of Guerrero and Michoacán, Mexico, reported extensive damage in mango trees caused by an abundant mycelial growth covering most diseased panicles of mango trees cv. Haden. Materials and methods. The fungus was isolated from panicles of mango. Pathogenicity was evaluated in the orchard by inoculating 20 inflorescences protected by cellophane paper bags. In vitro characterization was evaluated on monosporic cultures; conidial morphology and rate of growth were determined. A molecular characterization by DNA extraction was carried out to identify the microorganism. Results. Cladosporium tenuissimum caused necrosis of flowers, pedicels and small fruits on inoculated mango panicles cv. Haden in the long coast of Guerrero and Michoacan States of Mexico. The affected organs were covered with grey cottony mycelia and an olivaceous, green to grey sporulation. In vitro, young colonies were also olive green and velvety, turning dark green to grey with a whitish outer margin. The growth rate of colonies was 0.46 cm•day-1. Conidia were subspherical, lime-shaped and fusiform, olivaceous in color with visible scars and denticle-like extensions. The mean size of conidia was (5.85 × 2.93) µm with variations of 3.2-23 µm × 1.98-5.47 µm. The molecular characteristics rendered C. tenuissimum after identification. Symptoms of inoculated or naturally infected tree organs were similar. A diagrammatic scale was developed for the evaluation of disease severity, which varied from 69% to 100% in infected panicles. The organs were susceptible from blooming to fruit set. Discussion. Further research is proposed to evaluate the geographical distribution of C. tenuissimum in the production areas of mango with the concomitant evaluations of strategies of control. Mexico / Mangifera indica / plant diseases / Cladosporium tenuissimum / identification / symptoms Caractérisation morphologique et moléculaire de Cladosporium tenuissimum Cooke (Deuteromycotina: Hyphomycètes) sur panicules de manguier : symptômes, pathogénicité et sévérité du champignon. Résumé-Introduction. Les producteurs de mangues de deux importantes régions productrices du Mexique (États de Guerrero et de Michoacán) ont signalé la présence d'importants dommages en vergers, provoqués par une abondante croissance mycélienne couvrant la plupart des panicules malades de manguiers du cv. Haden. Matériel et méthodes. Le champignon a été isolé sur des panicules de manguier. La pathogénicité a été évaluée en verger en inoculant 20 inflorescences protégées par des sacs en papier de cellophane. La caractérisation in vitro a été évaluée sur des cultures monospores ; la morphologie et le taux de croissance des conidies ont été déterminés. Une caractérisation moléculaire par extraction d'ADN a été effectuée pour l'identificatio...

Efecto de factores climatológicos sobre la fluctuación de esporas en árboles de mango cv. Ataulfo en Guerrero, México

“…La presencia de enfermedades del mango, causadas por hongos fitopatógenos y su impacto en la producción y calidad de los frutos ha sido ampliamente estudiada por varios autores (Ploetz, 2003;Acosta-Ramos et al, 2003;Guillén-Sánchez et al, 2007;Huerta-Palacios et al, 2009;Noriega-Cantú et al, 1999).…”

“…Los órganos afectados se cubrieron con un micelio algodonoso gris y una esporulación olivácea verde gris. Después de la identificación, las características moleculares representaron a C. tenuissimum (Guillén-Sánchez et al, 2007).…”

“…La medición de conidios de Cladosporium se realizó en imágenes digitales de microscopio electrónico de barrido (Jeol ® modelo 5800 LV), midiendo en promedio 4.8 x 1.78 µm, con variación de 1.5 -1.6 x 0.28 -0.62 µm. Estos valores indican una variación reducida, pero son 1.05 y 1.15 µm menos al tamaño de esporas reportado por Guillén-Sánchez et al (2007) para Cladosporium tenuissimum, que hicieron mediciones en fotomicroscopio y por tanto con diferente 4.8 x 1.78 µm, with a variation of 1.5 -1.6 x 0.28 -0.62 µm. These values indicate a reduced variation, but they are 1.05 and 1.15 µm less than the size of spores reported by Guillén-Sánchez et al (2007) for Cladosporium tenuissimum, who carried out measurements in a photomicroscope, and therefore with a different treatment to the study material, which explains the numerical differences recorded.…”

“…The region with the highest production and surface planted in the state of Guerrero is the Coast (SAGARPA, 2016); 33 % of its surface is covered with the variety Manila, followed by Ataulfo and Haden, and 30 and 16 %, respectively. The presence of mango diseases caused by pathogenic fungi and their impact on the production and quality of fruits has been widely studied by several authors (Ploetz, 2003;Acosta-Ramos et al, 2003;Guillén-Sánchez et al, 2007;Huerta-Palacios et al, 2009;Noriega-Cantú et al, 1999).…”

“…The organs affected were covered with a gray cotton-like mycelium, and a grayish-olive green sporulation. After its identification, the molecular characteristics represented C. tenuissimum (Guillén-Sánchez et al, 2007).…”