Characterization of fungi associated with black foot disease of grapevine (Vitis vinifera L.) in Peru

• Autor(a) principal: Torcato, Cristina Sofia Fernandes
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/24638
• topic: Fungi; Vitis vinifera; Fusarium; Clonostachys; Pleiocarpon; Cylindrocladiella; Peru; Black foot disease

Gravepine trunk diseaseas (Vitis vinifera L.) are mostly caused by fungi, which can cause serious economic losses worldwide. One of these diseases is Black Foot Disease. The most common symptoms are necrotic root lesions, reduced root biomass, under-bark black discoloration, and necrosis of xylem tissue at the base of the rootstocks. Over the last decade, the intensity and the incidence of the disease increased, causing loss of productivity and death of young grapevines. In this study were characterized a collection of 138 fungi isolated from grapevine in Peru with Black foot disease symptoms. Primarily, a genetic typing of the isolates was performed to assess the genetic diversity of the isolate collection. Identification by sequencing and analysis of the Internal Transcribed Spacer (ITS) was carried out with 38 representative isolates of the diversity. This allowed the initial identification of the genera Fusarium, Cylindrocladiella and Clonostachys. Afterwards, it was done a secondary marker analyses to allow a correct identification of the isolates to the species level. Sequences of the Translation elongation factor 1- alpha (tef1-α) were obtained for all the isolates, allowing the identification of the genus Pleiocarpon, previously unidentified when using the ITS region. The partial sequence of the gene that codes for β–Tubulin (tub2) was used to differentiate the species of Clonostachys and Cylindrocladiella. The phylogenetic analyses with the combined sequences of ITS and tef1-α for the genera Cylindrocladiella and Pleiocarpon indicated the presence of the species Cylindrocladiella peruviana and Pleiocarpon strelitziae. The phylogenetic analyses of the combined sequences of ITS, tef1-α and tub2 confirmed the identity of C. peruviana. The species P. strelitziae was described for the first time in association with symptomatic grapevine. The phylogenetic analyses of genus Fusarium/Neocosmospora using tef1-α sequences allowed to group 26 isolates in three different species complexes: 12 in Neocosmospora solani species complex, 1 in Fusarium incarnatum-equiseti species complex and 13 in Fusarium fujikuroi species complex. The Fusarium/Neocosmospora species are not normally associated with grapevine Black Foot Disease. Their potential involvement in this pathology needs to be studied in the future. The phylogenetic analyses of the combined sequences of ITS and tub2 and ITS, tef1-α and tub2 of the genus Clonostachys indicated that the isolates of these genus belong to two possible new species Clonostachys viticola and Clonostachys peruviana. These species were characterized in terms of morphology and growth rates at different temperatures, and taxonomic descriptions are given for both