Fitopatologia - Artigos

URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741

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1990 - 19995

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Autor: search.filters.author.Romeiro, Reginaldo da SilvaData inicial: 1990Data final: 1999

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Agora exibindo 1 - 5 de 5
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    A new bacterial disease of tomato in Viçosa, Minas Gerais state
    (Revista Ceres, 1995-05) Oliveira, José Rogério de; Miguel, Dulândula Silva; Romeiro, Reginaldo da Silva
    In 1991 it was observed a new disease of tomato in commercial plantations at the region of Viçosa, Minas Gerais State, Brazil. The disease shows up as necrotic lesions in leaves, either irregularly round or along leaf borders, initially small and increasing in size with age. These lesions are usually surrounded by a chlorotic halo. Drop exsudate tests indicated a bacterial etiology for the disease. From such lesions, it was consistently isolated a bacterium that gives rise to clear, opaque, regular, elevated and shinning colonies. Inoculations tests rendered HR in leaves of coffee, tobacco, bean and passion fruit as well as typical disease symptoms in tomato leaves. The bacterium is a single, regular, straight, Gram-negative, strictly aerobic rod, unable to use asparagine as sole C and N source, unable to produ-ce xanthomonadins, does not induce hipertrOphic growth in the host, produces a blue fluorescent pigment, grows easily in routine culture media and was positioned in the genus Pseudomonas, fluorescent group. Biochemical, staining and biological tests indicate the pathogen belongs to the species Pseudomonas syríngae pv. tomato,
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    Atividade bacteriocinogênica entre isolamentos de Xanthomonas campestris pv. Arracaciae
    (Revista Ceres, 1999-01) Siqueira, Marita Francisca de; Romeiro, Reginaldo da Silva
    Twenty four isolates of Xanthomonas campestris pv. arracaciae were tested against each other for production and sensibility of bacteriocins, Only five isolates behaved as producers and two did work as indicators. This is the first report on bacteriocin production by the pathovar.
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    Sensibilidade de fitobactérias às substâncias com propriedades antimicrobianas presentes em extratos de folhas de fumo inoculadas do patógeno incompatível Pseudomonas syringae pv. pisi
    (Revista Ceres, 1990-05) Silva, Talmir Duarte da; Romeiro, Reginaldo da Silva
    Plantas de fumo (Nicotiana tabacum cv. 'Turkish' foram inoculadas de uma suspensão de células do patógeno incompatível Pseudomonas syringae pv. pisi. Vinte e quatro horas após, porções do limbo foliar, com sintomas típicos de reação de hipersensibilidade, foram submetidas à extração, pelo método de difusão facilitada (17), em etanol, a 40%. O extrato etanólico, concentrado, a vácuo, foi fracionado com acetato de etila. A fração acetato de etila revelou conter substâncias com propriedades antimicrobianas. Fitobactérias patogênicas para o fumo revelaram-se insensíveis à atividade presente no extrato, ao passo que as não-patogênicas para o fumo tiveram sua mutiplicação inibida.
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    Queima bacteriana (Xanthomonas campestris) do alho-poró (Allium porrum) em Minas Gerais, Brasil
    (Revista Ceres, 1999-01) Moura, Andréa Bittencourt; Romeiro, Reginaldo da Silva
    A leek disease found in Vicosa, Minas Gerais, showed pale apical lesions progressing downward from the leaf apex which later became necrotic. These leaves are completely taken up by the infection, dry up and fall off, while the plant remains alive. One bacterium producing medium yellow, shining, regularly edged, elevated colonies was isolated in a standard culture medium. It was unable to induce HR in beans, coffee, passion fruit, tobacco and tomato but induced the same observed leaf symptoms when reinoculated into healthy leek plants. The isolated bacteria are straight, regular, rod-shaped, Gram-negative cells, unable to use asparagine, strict aerobes, xanthomonadin-producers, non tumorogenic and can be positioned in Xanthomonas. Biochemical tests identified X. campestris as the species. The disease may be seed transmitted.
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    Bacterial blight (Xanthomonas campestris) of suflower (Helianthus annuus), a new disease
    (Revista Ceres, 1998-05) Romeiro, Reginaldo da Silva; Moura, Andréa Bittencourt
    In Vicosa, Minas Gerais, Brazil, a disease in sunflower (Helianthus annuus) was observed, whose symptoms show up as necrotic lesions, always surrounded by chlorotic haloes, predominately located at the leaf margin and, less frequently, dispersed in the leaf limb. The same lesion patterns were also visualized in stem and flower parts. Lesion fragments mounted in water and observed under the lowest microscope magnification showed cepious bacterial streams indicating a bacterial etiology for the disease. From lesions a bacterium was isolated that produces yellow, shining, regular edges, elevated colonies in standard culture media, able to induce HR in bean leaves and to reproduce original symptoms if inoculated in the host. Isolates are straight, regular, rod-shaped cells, Gram-negative, unable to use asparagine a sole Carbon and/or Nitrogen source, strict aerobes, xanhomonadines producers, are not tumorogenic and can be positioned in the genus Xanthomonas. Biological, biochemical and staining tests lead to the identification of the pathogen as Xanthomonas campestris. Its is not known the way by which the pathogen was introduced in the region but it might be through botanical seeds, Losses to the pathogen are very severe in spite of that fact that plant death was not observed or suppression of flower production. A preposition for creation of a new pathovar "Silvia", being, as a consequence, the name of the pathogen Xanthomonas campestris pv. silvia has been made.