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Diversity and prospecting of endophytic fungi from Begonia species found in the Atlantic Rain Forest

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Ana Maria Lima Correia
Total Authors: 1
Document type: Master's Dissertation
Press: Botucatu. 2016-05-19.
Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu
Defense date:
Advisor: André Rodrigues; Simone Possedente de Lira

Endophytic fungi live within plant tissues without causing any apparent disease symptoms. Fungal endophytes may stimulate host defenses towards pathogens through the production of chemical compounds; thus they are a promising source for the discovery of new bioactive compounds. Using culture dependent methods coupled with a polyphasic approach for fungal identification, we evaluated the diversity of endophytic fungi associated with Begonia fischeri, Begonia olsoniae and Begonia venosa found in the Atlantic Rain Forest. In addition, we carried out in vitro bioassays from acetate fractions of the endophytic fungi towards the plant pathogens Phomopsis sojae and Colletotrichum gloeosporiodes, to verify the putative production of bioactive compounds. From 20 leaves analyzed of each species, a total of 426 endophytic fungi were obtained, comprehending 120 from B. fischeri, 151 from B. olsoniae and 155 from B. venosa. After screening the isolates and sequencing the ITS region, the sequences were clustered into Operational Taxonomic Units (OTUs) and ecological metrics applied at 97% similarity. Using this approach, we identified 46 taxa and the prevalent genera were Colletotrichum (51.6% of the total of 426 isolates) and Diaporthe (22.5%), followed by Phyllosticta (3.5%), Neopestalotiopsis (1, 8%), Stagonospora (1.8%) and Nigrospora (1.6%) among the genera found in minor abundance. Richness and diversity of fungi were higher in B. fischeri in comparison to B. olsoniae e B. venosa. Furthermore, correspondence analysis demonstrated that the host plant explains 24% of the observed differences among the endophytic community, suggesting that other environmental variables (e.g., sampling sites) may explain the community structure. From the 88 endophytes evaluated in the inhibition assays, 26% (n = 23) of the acetate fractions showed activity against at least one phytopathogen. These results are promising and indicate that endophytic fungi these plants are an untapped source for prospecting antifungal compounds. (AU)

FAPESP's process: 14/12021-5 - Endophytic fungi from Begonia sp. in Alcatrazes Island and the continental zone: diversity and prospection for bioactive compounds
Grantee:Ana Maria Lima Correia
Support Opportunities: Scholarships in Brazil - Master