Controle pós-colheita da antracnose do pimentão pela levedura Rhodotorula glutinis / Post-harvest control anthracnose in pepper by yeast Rhodotorula glutinis

Considerando as perdas causadas em pós-colheita pela antracnose no pimentão e à ineficácia das medidas de controle atualmente utilizadas, este trabalho teve por objetivo estudar a potencialidade antagônica in vitro e in vivo de quinze isolados de leveduras à Colletotrichum sp., agente causal da antracnose em pimentão. Foi calculada a porcentagem de inibição do crescimento do fungo dos tratamentos em relação à testemunha nos testes in vitro e determinado o tamanho da área lesionada em frutos através da mensuração do comprimento da lesão em dois sentidos diametricamente opostos nos testes in vivo. As leveduras que obtiveram o melhor resultado no controle da antracnose foram identificadas através de características macroscópicas, microscópicas, fisiológicas, bioquímicas e por taxonomia molecular, sendo os isolados de levedura 13E e 13A1, os que obtiveram as melhores respostas no controle do fitopatógeno tanto in vitro quanto in vivo, identificados como pertencentes à espécie Rhodotorula glutinis.

Considering the losses caused by post-harvest anthracnose in sweet pepper chili and ineffectiveness of control measures currently used, this study had the objective of evaluate the antagonistic potential in vitro and in vivo of fifteen isolates of yeast to Colletotrichum sp., the causal agent of anthracnose on pepper. By calculating the percentage growth inhibition of the fungus treatment compared to the control tests in vitro and determining the size of lesions via the measurement of lesion length in both directions diametrically affixed in vivo tests. Yeasts who obtained the best result in controlling anthracnose were identified by characteristic macroscopic, microscopic, physiological, biochemical and molecular taxonomy. In this study, the yeast isolates 13E and 13A1, which obtained the best results in controlling the pathogen both in vitro and in vivo of the species Rhodotorula glutinis.

Evaluación de métodos para la conservación de hongos fitopatógenos del ñame (Dioscorea sp) / Evaluating methods for preserving yam (Dioscorea sp) phytopathogenic fungii

Un elemento esencial en la investigación con microorganismos fitopatógenos es su conservación y uso seguro.Desde este punto de vista, en este estudio se evaluaron métodos de conservación de hongos que atacanel ñame, empleando como factores de respuesta el potencial de viabilidad, y la estabilidad y presencia o ausenciade cambios en las características macro y microscópicas. Como resultado del trabajo se proponen los métodos más adecuados para los géneros Colletotrichum y Fusarium, hongos causantes de las mayores pérdidasen las plantaciones de ñame en la Costa Caribe colombiana. Las cepas utilizadas en este estudio provienen de las colecciones de la Universidad de Sucre, del Instituto de Biotecnología de la Universidad Nacional de Colombia (IBUN) y de una donación de la doctora Lucía Afanador de la Universidad Nacional, Sede Medellín.Estas fueron sometidas a diferentes métodos de conservación, entre ellos criopreservación, liofilizacióny cultivo periódico con y sin aceite mineral. Los resultados obtenidos permitieron elegir la criopreservacióncomo el método más eficiente para la conservación de la colección, y el cultivo periódico con aceite mineralcomo método alternativo y complementario. Estos minimizan el riesgo de pérdida del material biológico y brindan condiciones de manejo que conservan las características biológicas bajo estudio desde campos comola microbiología, la bioquímica y la biología molecular, entre otros.

An essential element in phytopathogenic microorganism research is their preservation and safe use. The purposeof this study was to evaluate methods for preserving fungi producing diseases in yam, using potential viability, stability and the presence or absence of macro- and microscopic characteristic changes as response factors. More suitable methods for Colletotrichum and Fusarium genera were proposed as a result of the work; these are fungi causing the greatest losses in yam plantations on the Colombian Caribbean Coast. The strains used in this study came from collections kept at the University of Sucre and the Universidad Nacional de Colombia’s Institute of Biotechnology (IBUN) in Bogota and a donation from Dr Lucia Afanador from the Universidad Nacional in Medellín. These strains were subjected to different preservation methods, including cryopreservation, lyophilisation and periodic culture with and without mineral oil. The results led to choosing cryopreservation as the most efficient method for preserving the collection and the periodic culture withmineral oil as an alternative and complementary method. These minimised the risk of biological material loss and provided handling conditions conserving the biological characteristics of the fungi being studied from the fields of microbiology, biochemistry and molecular biology.