Diversity of fungi associated with macroalgae from Ria de Aveiro

• Autor(a) principal: Vicente, Tânia Filipa Lopes
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/29246
• topic: Algicolous fungi; Phylogeny; Salt Marsh; Taxonomy; Fungal Diversity; Cladosporium rubrum; Hypoxylon aveirense

Ria de Aveiro has been explored with the aim of unveiling the microbial community sheltered by the plants in this habitat. Algae, a group well established, are organisms little explored in this lagoon. Fungi are organisms which can establish different relations of symbiosis with algae. Beyond this, it is known that these fungi produce bioactive compounds with interesting properties such as antioxidant activity, antialgal, antiviral, antiinsect and antifungal. This study aimed to the characterize the diversity of algicolous fungi associated with different macroalgae in Ria de Aveiro. From the 7 sites randomly selected, it was chosen 26 algae samples belonging to Ulva, Fucus, Enteromorpha, Gracilaria, Cladophora, Ceramium, Codium and Scinaia. After fungal isolation and molecular typing, it was made the identification of 486 isolates through the sequencing of ITS (Internal Transcribed Spacer) belonging to ribosomal cluster. The main fungal groups detected belonged to the genera Cladosporium, Leptobacillium, “Acremonium-like species”, Alternaria, Penicillium and other ascomycetes. All these (except Leptobacillium) were already described in marine environments. Leptobacillium, a soil fungus, appears here as a new record in algicolous communities. In addition, this study included the complete characterization and taxonomic description of two new species: Cladosporium rubrum sp. nov. and Hypoxylon aveirense sp. nov. The diversity of fungial communities of samples was analysed using the Shannon´s, Simpson and Pielou indices. Results demonstrated that a red alga (unidentified) and two samples belonging to genus Fucus were the ones with highest diversity. With the aim of investigate if there is some influence of the site sampling and/or host, it was performed parametric tests (ANOVA) and/or non-parametric (“Kruskal-Wallis rank sum”) to determine the presence of significant differences between the samples. It was only detected significant differences between the evenness of the samples belonging to red algae, where the evenness is significantly higher than the green algae. Posterior analysis of the data obtained (using the multipatt function) allowed the detection of a preference distribution of the isolates belonging to Exophiala sp. in samples of Ceramium sp. and Scinaia sp, and Emericellopsis spp. by red and green algae. Considering the sampling sites, it was observed the association of some fungal genera with specific sites where their expression was higher. Such differences between communities can be related with abiotic factors (salinity differences), as well as biotic factors (anthropogenic influence). Concluding, this study contributed for the knowledge about the algicolous fungi communities from Ria de Aveiro, while reinforces the necessity for more taxonomic studies in Portuguese marine environments.