Microbiologia

URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840

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2005 - 200912010 - 20182

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Autor: search.filters.author.Kasuya, Maria Catarina MegumiAssunto: search.filters.subject.Symbiosis

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Cyrtopodium paludicolum germination with two Tulasnella isolates
    (Acta Botanica Brasilica, 2018-01) Carvalho, Otieres Cirino de; Paiva Neto, Vespasiano Borges de; Padilha, Daly Roxana Castro; Veloso, Tomás Gomes Reis; Bocayuva, Melissa Faust; Soares, Deanna Carla Oliveira; Kasuya, Maria Catarina Megumi
    Symbiosis between orchid seeds and mycorrhizal fungi has been reported to be a determining factor in the success of germination and protocorm development in vitro. Th e aim of this study was to isolate and identify by molecular analysis the mycorrhizal fungus associated with Cyrtopodium paludicolum, and to evaluate its effi ciency in facilitating seed germination and development. Germination experiments were carried out using a fungus isolated from C. paludicolum (CH01) and Epidendrum secundum (M65), which has been successfully used a number of times in symbiotic germination. Th e experiments were conducted in a completely randomized design with treatments of CH01, M65 as well as under asymbiotic conditions. Th e mycobiont CH01 was successfully isolated from Cyrtopodium paludicolum and identifi ed as Tulasnella sp. Treatments with both fungi reached a higher germination percentage than under asymbiotic conditions, indicating no specifi city in the relationship between Cyrtopodium paludicolum and the fungi. Th e results presented have the potential to advance research into the propagation and conservation of C. paludicolum, a native of the Cerrado biome.
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    Morphological and molecular characterization of Tulasnella spp. fungi isolated from the roots of Epidendrum secundum, a widespread Brazilian orchid
    (Symbiosis, 2014-02) Pereira, Marlon Corrêa; Coelho, Irene da Silva; Valadares, Rafael Borges da Silva; Oliveira, Sabrina Feliciano; Bocayuva, Melissa; Pereira, Olinto Liparini; Araújo, Elza Fernandes; Kasuya, Maria Catarina Megumi
    Tulasnella spp. are the main fungal symbionts of Brazilian Epidendrum orchids. The taxonomy of these fungi is largely based on ITS rDNA similarity, but culture dependent techniques are still essential to establish the true biological entity of the mycobiont. The aim of this study was to characterize morphologically and molecularly 16 Tulasnella spp. fungi isolated from three different populations of E. secundum and to test the coincidences between morphological and molecular characterization. Two uninucleate rhizoctonia fungi, obtained from Oncidium barbaceniae, and two phytopathogenic isolates were included as outgroups. Qualitative and quantitative morphological characteristics were analyzed using multivariate statistics and were able to distinguish Ceratobasidium, Tulasnella and Thanatephorus genera and separate the isolates of Tulasnella spp. into two groups. Analysis of RAPD (Random Amplified Polymorphic DNA) and ITS rDNA sequences validated the morphological data. Symbionts of O. barbaceniae presented identity to ITS sequences of Ceratobasidium genus, while E. secundum isolates presented identity to two species of Tulasnella. We observed homogeneity among Tulasnella spp. obtained from a single population and from neighboring populations, but there was higher variability among isolates obtained from populations of regions that were farther apart. Morphological data associated with multivariate statistics proved to be a useful tool in the multi-level taxonomy of these orchid-associated fungi and in estimating the diversity of orchid mycorrhizal fungi.
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    Morphological and molecular characterization of mycorrhizal fungi isolated from neotropical orchids in Brazil
    (Canadian Journal of Botany, 2005-01) Pereira, Olinto Liparini; Kasuya, Maria Catarina Megumi; Borges, Arnaldo Chaer; Araújo, Elza Fernandes de
    To initiate a conservation program of the Orchidaceae from the Brazilian Atlantic rain forest with the purpose of ex situ conservation or reintroduction in the State of Minas Gerais, seven mycorrhizal Rhizoctonia-like fungal strains were isolated from roots of seven neotropical orchid species from three different Atlantic rain forest fragments. Taxonomic studies revealed that the isolates belong to the genera Ceratorhiza and Epulorhiza. The Epulorhiza isolates were identified as Epulorhiza repens (N. Bernard) R.T. Moore and Epulorhiza epiphytica Pereira, Rollemberg et Kasuya. RAPD analysis indicated higher polymorphism between Epulorhiza epiphytica and Epulorhiza repens than found in the PCR RFLP analysis. RAPD and morphological analyses indicated a degree of relatedness among the Ceratorhiza isolates obtained from the roots of different Oncidium species. A combination of morphological and molecular characterizations permitted integration of fungal strain identification with genetic relatedness among the isolates, thus allowing some inferences to be made on specificity of these endosymbionts under field conditions.Key words: biodiversity, Ceratorhiza, Epulorhiza, orchid mycorrhiza, Rhizoctonia-like, symbiosis, specificity.