Caracterização biológica e isoenzimática de isolados de Colletotrichurn sp. em cafeeiro (Coffea arabica L.)
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Data
1999
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Universidade Federal de Lavras
Resumo
A população de Colletotrichum encontrada em cafezais pode ser distinta com base em parâmetros morfológicos e principalmente testes de patogenicidade. Neste experimento, foram avaliados 8 isolados de Colletotrichum de café, dos quais 2 foram obtidos de folhas, 5 de hastes, e 1 de fruto infectado provenientes de Minas Gerais e São Paulo, utilizando parâmetros morfológicos e testes de patogenicidade, além de verificar a viabilidade do uso de padrões eletroforéticos de isoenzimas como uma ferramenta adicional na taxonomia de fungos. Os caracteres morfológicos utilizados foram crescimento micelial e capacidade de esporulação in vitro em três meios de cultura (BDA, GYA, e MEA); medição de conídios; utilização de fonte de carbono; testes de patogenicidade em frutos verde sadios, plântulas de seis semanas e mudas de café da cultivar Mundo Novo. Os padrões eletroforéticos foram revelados para as enzimas álcool desidrogenase (ADH), fosfatase ácida (ACP), esterase (EST), e malato desidrogenase (MDH). Os resultados obtidos permitiram caracterizar os isolados de crescimento lento em todos os meios testados, com capacidade de esporulação maior em meio GYA. Os conídios do tipo cilíndrico, com exceção de 1-1 e 1-5, que apresentaram conídios cilíndrico curto, capacidade de utilizar citrato ou tartarato como fonte exclusiva de carbono, com resultado variável para 1-2. Os isolados foram patogênicos apenas em plântulas e frutos verdes. Comparando os padrões eletroforéticos obtidos, observou-se que o isolado saprófita foi distinto dos demais patogênicos por apresentar bandas
características em ADH, ACP e EST, confirmando assim a viabilidade do uso da técnica na identificação de raças patogênicas dentro de uma população fúngica
The population of Colletotrichum found in coffee plantations may be distinguished on the basis of morphological parameters and chiefly pathogenicity tests. In this experiment, were evaluated 8 Colletotrichum isolates of coffee, of which 2 were obtained from leaves, 5 from stems and 1 from fruit infected coming from Minas Gerais and São Paulo, by utilizing morphological parameters and pathogenicity tests, besides verifying the viability of the use of electrophoresis patterns of isoenzymes as an additional tool in fungus taxonomy. The morphological characters utilized were mycelial growth and sporulating capacity in vitro in three culture media (BDA, GYA and MEA); measurement of conidia; utilization of a carbon source; pathogenicity tests in healthy green fruits, six week seedlings and coffee cutting of the cultivar Mundo Novo. The electrophoresis patterns were stained to the enzymes alcohol dehydrogenase (ADH), acid phosphatase (ACP), esterase (EST) and malate desidrogenase (MDH). The results obtained enabled to characterize the slow growing isolates in every medium tested, with a greater sporulating capacity in GYA medium, cylindrical conidia, excepting 1-1 and 1-5 which presented short cylindrical types, capacity of utilizing either citrate or tartarate as a unique source of carbon, as variable results for 1-2.The isolates were pathogenic only in seedlings and green fruits. By comparing the electrophoresis patterns obtained, it was noticed that the saprophyte isolate was distinguished from the others for presenting characteristic bands in ADH, ACP and EST, confirming thus the viability of the use of the technique in identifying pathogenic races within a fungal population.
The population of Colletotrichum found in coffee plantations may be distinguished on the basis of morphological parameters and chiefly pathogenicity tests. In this experiment, were evaluated 8 Colletotrichum isolates of coffee, of which 2 were obtained from leaves, 5 from stems and 1 from fruit infected coming from Minas Gerais and São Paulo, by utilizing morphological parameters and pathogenicity tests, besides verifying the viability of the use of electrophoresis patterns of isoenzymes as an additional tool in fungus taxonomy. The morphological characters utilized were mycelial growth and sporulating capacity in vitro in three culture media (BDA, GYA and MEA); measurement of conidia; utilization of a carbon source; pathogenicity tests in healthy green fruits, six week seedlings and coffee cutting of the cultivar Mundo Novo. The electrophoresis patterns were stained to the enzymes alcohol dehydrogenase (ADH), acid phosphatase (ACP), esterase (EST) and malate desidrogenase (MDH). The results obtained enabled to characterize the slow growing isolates in every medium tested, with a greater sporulating capacity in GYA medium, cylindrical conidia, excepting 1-1 and 1-5 which presented short cylindrical types, capacity of utilizing either citrate or tartarate as a unique source of carbon, as variable results for 1-2.The isolates were pathogenic only in seedlings and green fruits. By comparing the electrophoresis patterns obtained, it was noticed that the saprophyte isolate was distinguished from the others for presenting characteristic bands in ADH, ACP and EST, confirming thus the viability of the use of the technique in identifying pathogenic races within a fungal population.
Descrição
Dissertação de Mestrado defendida na Universidade Federal de Lavras
Palavras-chave
Colletotrichum Caracterização biológica Caracterização izoenzimática Café Fungos fitopatogênicos, Colletotrichum Biological characterization Isoenzymatic characterization Coffee Pathogenic fungus
Citação
Nechet, Kátia de Lima. Caracterização biológica e isoenzimática de isolados de Colletotrichurn sp. em cafeeiro (Coffea arabica L.). Lavras : UFLA, 1999. 73 p. (Dissertação - mestrado em Agronomia, área de concentração: Fitopatologia) Orientador: Mário Sobral de Abreu