The objective of this study was to characterize isolates of biovar 2 of Ralstonia solanacearum pathogenic to eucalyptus "urograndis" hybrid by means of biochemical tests, as well as evaluation of host range and identification by PCR with primers for species, biovar and phylotype. Carbohydrate utilization assays revealed that the eucalyptus isolates belong to phenotype Tropical of biovar 2 (2T). From artificial inoculations it was possible to reproduce symptoms or recover the bacterium from: eucalyptus, potato, tomato, eggplant, datura, geranium, turnip, mustard, nasturtium, beetroot, sunflower, bean, French marigold, horseradish tree, and cashew. The PCR assays confirmed that the isolates belong to biovar 2, phylotype II of the bacterium. The confirmation of new biovar naturally infecting eucalyptus indicates that R. solanacearum easily adapts to new hosts.
FUNGI ON SEEDS OF ORNAMENTALSABSTRACT -A study was made to detect the occurrence of fungi on seeds of nine species of herbaceous ornamental species (Dahlia pinnata, Petunia x hybrida, Phlox drummondii, Rudbeckia hirta, Salvia farinacea, S. splendens, Tagetes patula, Viola tricolor and Zinnia elegans) planted in the Federal District of Brazil. Subsamples of 100 seeds of each species, with or without desinfection with 70% alcohol and 1% sodium hypochlorite, were submitted to the blotter test on filter paper to detect fungi. Fungal species from these seeds were detected and isolated on PDA 32, with 88% of specimens identified as mitosporic fungi, 6% as Ascomycota, 3% as Zygomycota, and 3% as Oomycota. Alternaria, Cladosporium, Bipolaris, Curvularia, Exerohilum, Aspergillus and Penicillium were the most frequently detected genera. The highest number of fungi occurred
Oito espécies de Ravenelia descritas anteriormente foram revisadas e acrescentadas ilustrações inéditas das características morfológicas de alguns desses fungos causadores de ferrugem em Leguminosae. As espécies de Ravenelia estudadas foram: Ravenelia bezerrae sobre Enterolobium ellipticum ; R. densifera sobre Senna silvestris; R. dieteliana sobre Calliandra dysantha. var. dysantha; R. geminipora sobre Platymenia reticulata; R. lonchocarpi sobre Lonchocarpus campestris; R. mimosae-sensitivae sobre Mimosa radula var. imbricata; R. pileolarioides sobre Caesalpinia pyramydales e R. santos-costae, sobre Calliandra dysantha.
Photoacoustic spectroscopy is introduced as a promising experimental technique to investigate fungus infected Acai (Euterpe oleracea) seeds. Photoacoustic spectra of healthy and infected Acai seeds with the fungus Colletotrichum gloeosporioides were recorded firstly in the modulation frequency range of 5 Hz to 700 Hz, while keeping the wavelength of excitation radiation of a Xe arc-lamp constant, to ascertain the depth of penetration of infection within the seed and secondly, at variable wavelength (wavelength scanning) in the interval 250 nm to 1,000 nm, while keeping the modulation frequency constant. In the former, the photoacoustic signal strength from the infected seed was found higher than that of the healthy one, and has been associated with the appearance of new biomolecules associated with the pathogen infection. In the latter, characteristics peaks and bands were observed in the range from 650 nm to 900 nm ascribed to organic compounds with carboxylates and amines (functional groups) forming the typical metabolic structures of the fungus.
O presente trabalho visou aprofundar o conhecimento do gênero Uromyces no Cerrado, através de uma descrição ilustrada do grupo de espécies mais disseminadas na região.As espécies de Uromyces estudadas e fotografadas em MEV apresentaram teliósporos lisos ou reticulados diferindo de Almeida (1975) que encontrou teliósporos lisos, rugosos, levemente reticulados e reticulados. As descrições que seguem não mostraram teliósporos rugosos em material do Cerrado.Finalmente, seis espécies de Uromyces sobre oito gêneros de Leguminosae, são ilustradas e descritas, mostrando detalhes da diversidade de espécies encontrada no bioma Cerrado. MATERIAL E MÉTODOSOs espécimes estudados pertencem à Coleção Micológica de Referência da Universidade de Brasília (CMRUnB) e são provenientes de áreas de Cerrado do Distrito Federal, Mato Grosso, Mato Grosso do Sul, Maranhão, Minas Gerais, Bahia, Espirito Santo e São Paulo. Taxonomistas dos herbários do Departamento de Botânica da Universidade de Brasília e da Reserva Biológica do IBGE assistiram os autores na identificação das plantas hospedeiras.Amostras das exsicatas rehidratadas foram cortadas em micrótomo de congelamento, marca Micron HM505E, temperatura de -20 a -21 °C, seguindo-se a montagem semipermanente em lâminas que foram coradas com lactofenol/ azul de algodão e observadas em microscópio ótico (MO). Solução aquosa de cloral hidratado foi usada quando se pretendia ver os poros germinativos dos esporos. Para a
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