Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2018.tde-20181127-155228
Document
Author
Full name
Erna Elisabeth Bach
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1991
Supervisor
Title in Portuguese
Comparação morfológica, patogênica, serológica e eletroforética de Exserohilum turcicum (Pass.) Leonard & Suggs., isolado de milho, sorgo e capim massambará
Keywords in Portuguese
CAPIM MASSAMBARA
ELETROFORESE
FUNGOS FITOPATOGÊNICOS
ISOLAMENTO
MILHO
MORFOLOGIA
PATOGENICIDADE
SEROLOGIA
SORGO
Abstract in Portuguese
Foram feitas comparações morfológicas, patogénicas, serológicas e eletroforéticas, de isolados de Exserohilum turcicum (Pass.) Leonard & Suggs. de diferentes hospedeiros (milho, sorgo e capim). Morfologicamente, os conÃdios dos isolados de capim apresentaram-se significativamente maiores do que os dos isolados de milho e sorgo em relação aos diâmetros. Testes de patogenicidade em milho, sorgo e capim massambará, mostraram que: isolado de milho dos Estados Unidos com lesão somente no milho, pode ser classificado como Exserohilum turcicum f.sp. zeae; e que isolados de sorgo, virulentos ao milho, sorgo e capim massambará podem ser classificados como Exserohilum turcicum f.sp. complexa; entretanto isolados de milho do Brasil, patogênicos ao milho e ao sorgo; e isolados de capim virulentos ao capim, fracamente virulentos ao milho e avirulentos ao sorgo não podem ser enquadrados em nenhuma formae speciales descritas. Os testes de dupla-difusão em ágar de antÃgenos extraÃdos de conÃdios eou micélios não conseguiram detectar qualquer distinção serológica entre os isolados. No teste de ELISA o antissoro do isolado de milho distinguiu os isolados de milho e sorgo dos isolados de capim. O antissoro do isolado de capim distinguiu isolados de capim dos de milho e sorgo, sendo que aparentemente os de sorgo apresentaram-se como intermediários. Análises eletroforéticas isoenzimáticas envolvendo esterase e peroxidase permitiram diferenciar os isolados entretanto, somente foi possÃvel associar os resultados de serologia com a eletroforese-esterase. Através da extração do DNA, digestão com enzima de restrição HpaI e análise eletroforética com coloração por prata, foi possÃvel observar que o tamanho dos DNAs de todos os isolados foram iguais. Os resultados sugerem que testes serológicos e eletroforéticos podem auxiliar no estudo taxonômico para análise de variação inter-especÃfica (ou inter-forma especial).
Title in English
Morphological, pathogenic, serological and electrophoretic comparisons of Exserohilum turcicum (PASS.) Leonard & Suggs., isolated from maize, sorghum and Johnson grass
Abstract in English
Morphological, pathogenic, serological and electrophoretic comparisons were made among isolates of Exserohilum turcicum (Pass.) Leonard & Suggs. from maize, sorghum and Johnson grass. Concerning morphology, it was observed that diameters of conidia of Johnson grass isolates were significantly larger than those of maize and sorghum. In laboratory and greenhouse conditions, plants from maize, sorghum and Johnson grass inoculated with isolates of Exserohilum turcicum showed: isolate of maize from the United States produced lesions only in maize stating that this isolate can be considered as Exserohilum turcicum f. sp. zeae; isolates of sorghum were virulent to sorghum, maize and Johnson grass stating that these isolates can be considered as Exserohilum turcicum f. sp. complexa; iso1ates of maize from Brazil were pathogenic to maize and sorghum; isolates of Johnson grass were virulent only to Johnson grass, inducing flecks to maize and a virulent to sorghum. These observations concerning isolates of maize from Brazil and of Johnson grass suggest that they can not be treated of formae speciales. Serological reactions in agar double diffusion tests with antigens extracted from conidia and mycelium did not distinguish any isolate from the others. In the DAS-ELISA test it was observed that antiserum produced against isolates of maize distinguished isolates of maize and of sorghum from isolates of grass. The antiserum produced against isolates of Johnson grass distinguished isolates of Johnson grass from isolates of maize and sorghum, and revealed that apparentely isolates of sorghum are intermediaries. Electrophoretic analysis with the isoenzimatic variation (peroxidase and esterase) differentiated the isolates however only the results from electrophoretic-esterase could an be associated with serological results. DNA extraction, digestion with HpaI enzyme, electrophoretic analyses and silver coloration demonstrated that the sizes of DNA from all isolates are the same. The results suggest that serological and electrophoretic tests can help the taxonomic studies in the analyse of inter-specific (or inter-formae speciales> variations.
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Publishing Date
2018-11-27