Permeabilização e ultraestrutura da parede celular de basidiósporos de Pisolithus microcarpus

• Autor(a) principal: Silvério, Merielle Angélica Martines
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5362
• topic: Parede celular; ectomicorriza; Hidrofobicidade da parede celular; Microscopia eletrônica; Cell wall; Ectomycorrhiza; Cell wall hydrophobicity; Electron microscopy; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::MICROBIOLOGIA AGRICOLA

Basidiospores of the ectomycorrhizal fungus P. microcarpus are characterized by impermeable, hydrophobic cell walls. These features are possibly related to the low germination percentages of these propagules and make it difficult the isolation of monokaryons and the use of these spores as inoculants. Sodium hypochlorite can be used as a permeabilizing agent of the cell wall of fungal spores. The aim of this study was to evaluate the effects of permeabilization treatments with commercial bleach on the cell wall ultrastructure and hydrophobicity, and on the viability and germination of P. microcarpus basidiospores. For this, fungal basidiospores, from fruiting bodies associated with Eucalyptus spp., were collected and permeabilized using different concentrations of bleach and times of exposure. After permeabilization, the basidiospores were analyzed by scanning and transmission electron microscopy. Surface hydrophobicity, viability, and germination of these propagules were also analyzed. The percentage of permeabilized basidiospores of P. microcarpus was proportional to the increases in bleach concentration and the exposure time. Basidiospores from different fruiting bodies differed significantly in their susceptibility to the permeabilization treatments with bleach and in the decrease of cell surface hydrophobicity after permeabilization. Changes in the ultrastructure of permeabilized basidiospores were observed at bleach concentrations of 15 and 50 %, with an exposure time of 40 s. For one basidiocarp, after permeabilization with bleach at 5 % for 40 s, 80% of the permeabilized basidiospores were viable. The plating of basidiospores permeabilized with 10% bleach for 40 s resulted in the production of colonies of P. microcarpus. The colonies appeared after 15 days of incubation of the permeabilized basidiospores in the presence of the host plant, E. citriodora. The germination percentage obtained, 0,001 %, was similar to those reported for non-permeabilized basidiospores. This work is the first report on the ultrastructure of the cell wall of basidiospores of P. microcarpus and contributes to the understanding of the recalcitrance of these propagules to germination.