Avaliação da expressão dos genes que codificam a proteína RAS e o fator de elongação EF1α em ectomicorrizas de Scleroderma laeve e Eucalyptus grandis

• Ano de defesa: 2011
• Autor(a) principal: Pereira, Maíra de Freitas
• Orientador(a): Araujo, Elza Fernandes de
• Banca de defesa: Bazzolli, Denise Mara Soares , Pereira, Olinto Liparini
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Microbiologia Agrícola
• Departamento: Associações micorrízicas; Bactérias láticas e probióticos; Biologia molecular de fungos de interesse
• País: BR
• Palavras-chave em Português: Scleroderma laeve; Proteína Ras; Fator de elongação EF1α Ectomicorrizas; Expressão gênica
• Palavras-chave em Inglês: Scleroderma laeve; Ras protein; Elongation factor EF1α Ectomycorrhizas; Gene expression
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA
• Link de acesso: http://locus.ufv.br/handle/123456789/5339

The ectomycorrhizal association is a mutualistic interaction between plant roots and soil fungi that causes morphophysiological changes in the plant root system. The nutritional benefits result from the capacity of the fungus to increase the uptake of mineral nutrients by the host plant in exchange for photoassimilates. For the ectomycorrhizal association between Scleroderma laeve and Eucalyptus grandis, there is no information on which genes are decisive for the symbiosis and how they relate to the formation of ectomycorrhizas. Transcripts of the genes ras and ef1α were dentified as differentially expressed in many symbiotic associations and are related to signal transduction pathways and protein synthesis, respectively. Thus, the objectives of this work were to establish the ectomycorrhizal association between S. laeve and E. grandis in vitro, to isolate partial sequences of the genes ras and ef1α of S. laeve, and to evaluate the functional expression of these genes during ectomycorrhizal formation. Our works demonstrates the ectomycorrhizal association between S. laeve and E. grandis in vitro for the first time. The typical structures of ectomycorrhizas, such as the mantle and the Hartig net, were observed. At three days of contact between S. laeve and E. grandis roots the beginning of mantle formation could be observed. At 15 days, the mantle was completely formed, the epidermal cells were elongated, and the Hartig net formation was in progress. At 30 days, the ectomycorrhizas presented all the typical morphological structures fully developed. To evaluate gene expression during the association, partial sequences of ras and ef1α were isolated and the transcripts evaluated at the pre-symbiotic phase and at 3, 15 and 30 days after physical contact of the fungus with the plant roots. The transcripts of the gene ef1α were expressed at all evaluated times. Transcripts of ras were only detected in the ectomycorrhizas after three, 15, and 30 days of contact. These results are fundamental for a better understanding of the ectomycorrhizal association between S. laeve and E. grandis and suggest that ras-mediated signal transduction pathways may be functional during the establishment of the symbiosis between the fungus and the host roots.