Contribuições para o conhecimento dos fungos fitopatogênicos associados à espécie ameaçada Euterpe edulis e para o esclarecimento do complexo Trichoderma harzianum

• Ano de defesa: 2011
• Autor(a) principal: Rocha, Fabiano Branco
• Orientador(a): Barreto, Robert Weingart
• Banca de defesa: Costa, Maurício Dutra , Evans, Harold Charles , Furtado, Gleiber Quintão
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitopatologia
• Departamento: Etiologia; Epidemiologia; Controle
• País: BR
• Palavras-chave em Português: Taxonomia de fungos; Conservação de fungos; Micologia
• Palavras-chave em Inglês: Taxonomy of fungi; Conservation of fungi; Mycology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1037

Three studies covering different area of mycology were developed: 1) A study aiming at exploring the morphological diversity of Trichoderma harzianum sensu latu represented by eighty-one isolates recognized as belonging to this species-complex, seeking for disjunction of morphological characters matching/reflecting the twelve different clades recognized by a previous molecular-phylogeny study in support for the distinction and recognition of these taxa as separate cryptic species within the “T. harzianum complex”; 2) A taxonomic study about the species of fungi found as parasites associated with an Arecaceae native from Brazil Euterpe edulsi (palmito-juçara), and listed as endangered of extinction; 3) An attempt to clarify the host range of the fungi found associated with two species of Brazilian plants endangered of extinction - Coussapoa floccosa (Cecropiaceae) and E. edulis. The elucidation of the “T. harzianum complex” has special relevance for biological control of plant diseases, since isolates belonging to this taxon are widely investigated and used for that purpose. Since its first description, T. harzianum was recognized as a fungal species that has a high degree of morphologically diversity, a broad geographical distribution and the ability to exploit a wide range of niches. More recently molecular phylogenetic studies have further indicated that this species may be a species-complex including several cryptic species. The search for key morphological differentiation that would support the distinction of the twelve clades unraveled by the molecular studies did not yield any consistent character to be used with that purpose. Nevertheless, it appears that there is partial support for clade distinction based on niches and habitats occupied by distinct groups of isolates and based on geographic distribution of clade-members. At the present state of the art for this taxon, it appears more logical to continue to treat the populations that fit into the ”T. harzianumi complex” under the old name until more substantial evidence and consistent characters or well defined clades are found allowing for a precise distinction of the cryptic species (or infra-specific taxa) that are included. Four species of anamorphic fungi were described in association with Euterpe edulis: Bipolaris cynodontis, Distocercospora sp., Melanographium sp. and Passalora eitenii. The host range of these fungi, as well as of the fungi associated with Coussapoa floccosa, were studied through inoculations under controlled conditions (host-specificity tests), by seeking for possible alternative hosts in the field and by means of using sentinel-plants. None of the fungi originally associated with C. floccosa were found in association with other host of Rosales in the field and among the fungi associated originally with E. edulis, Melanographium sp. showed to be specific to the genus Euterpe whereas Distocercospora sp. was only capable to parasite E. edulis.