Evaluación de hongos y bacterias aislados de gallinaza en el biocontrol de Sclerotium cepivorum Berk

Abstract

<p>Objetivo. Seleccionar hongos y bacterias de la gallinaza por su capacidad antagónica en el biocontrol de S. cepivorum in vitro y en invernadero. Materiales y métodos. De dos fuentes de gallinaza, una pura y otra compuesta, se tomaron sendas muestras de 100 g, se colocaron en erlemeyers, se agregó agua destilada estéril hasta completar un litro y se agitó durante 5 minutos. A partir de esta suspensión se prepararon diluciones de 1x10-1 hasta 1x10-4, y se evaluó el crecimiento y esporulación de S. cepivorum. Los microorganismos seleccionados in vitro fueron evaluados en el control de la enfermedad en invernadero. Se evaluó la incidencia de la enfermedad y el porcentaje de plantas muertas. Resultados. De las dos fuentes de gallinaza se aislaron 13 colonias de hongos y 26 de bacterias, para un total de 39 aislamientos, de los cuales, tras ser evaluados in vitro, fueron seleccionados tres aislamientos de hongos (H2, H5, H6) y una <br />bacteria (B21) por su capacidad antagónica a S. cepivorum, a los 6, 9, 12 y 15 días, y la producción de esclerocios, con diferencias altamente significativas en comparación con el testigo. Los aislamientos H2 y H6 corresponden al género Trichoderma; el H5, a Penicillium, y B21, a Bacillus. Con H2, H5, H6 y B21, los síntomas de la enfermedad fueron observados en la semana 13, con una incidencia del 20%, y en el testigo, en la semana novena, con una incidencia del 70%, y 40% de muerte de plántulas. Conclusión. Las gallinazas son una fuente de microorganismos biocontroladores de S. cepivorum.</p>

Rhizobacteria antagonistic to the fungus Sclerotium cepivorum (Berk.t) in onion plants (Allium cepa L.)

“…On the other hand, the S. cepivorum fungus was isolated and morphological characteristics were observed showing abundant whitish mycelium, formation of black, round sclerotia, which had a diameter of 54 nm on average per sclerotia (Figure 1A and 1B ); the results coincide with what is described in the taxonomic keys of Imperfect Fungi (Sarmiento and Velandía, 2013).…”

“…Onion crops are affected by white rot disease, caused by the fungus Sclerotium cepivorum (Berk.) Is one of the most important (Sarmiento and Velandía, 2013;Castillo et al, 2016) ;; because it affects the genus Allium (onion, garlic, leek); the onion is affected at any stage of development, the infection increases as the radical system grows, the bulb and can cause losses up to 100% of the crops. In Mexico, it was first presented in Zacatecas in 1990 (Colina, 2017;Reveles-Hernández et al, 2014).…”

“…The most affected states are: Aguascalientes, Chihuahua, Guanajuato, Jalisco, Morelos, Michoacán, Puebla, Querétaro, Tlaxcala and Zacatecas (Velásquez-Valle and Reveles Hernández, 2016). (Sarmiento and Velandía 2013;Castillo et al, 2016). The sclerotia are stimulated by sulfur compounds present in the radical exudates of the onion plant such as: aquil cysteine and sulfoxides, easily disseminated and that once established in the soil can remain for several decades (Ortega et al, 2011;Reveles -Hernández et al, 2014;Hussain et al, 2017;Elshahawy et al, 2017), these produce volatile compounds of allyl and n-propyl sulfide (Coley-Smith et al, 1990), the mycelium contains material of reserve, which allows them to remain at rest when the environmental conditions are adverse (Vera et al, 2005;Ortega et al, 2011), due to the viability of up to 90% and being able to remain inactive for up to 40 years (Reveles-Hernández et al, 2014), these are activated when the environmental conditions are favorable, in the presence of sulfur compounds produced by the onion tuber (Coley-Smith et al, 1990).…”

Broccoli Seedling Production in Response to Recognised Organic Inputs

“…Similarly, poultry manure can contribute to diverse beneficial microorganisms that help plant nutrition and health. Sarmiento and Velandía (2013) found biocontrol microorganisms corresponding to the genera Trichoderma, Penicillium and Bacillus.…”

Isolation, identification and characterization of antagonistic rhizobacteria to Sclerotium cepivorum

“…The fungus Sclerotium cepivorum and 656 rhizobacteria were isolated from onion plants. The fungus was isolated and identified by its morphological traits described in the taxonomic codes of Sarmiento and Velandía (2013). Out of the isolated bacterial diversity, only 23 isolations presented antagonistic activity and only three of these were larger than 20 mm and the percentages of inhibition of the rhizobacteria against S. cepivorum were between 21 and 24% (Table 1).…”