Banca de DEFESA: Alexandra Martins Costa

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Alexandra Martins Costa
DATE: 02/02/2024
TIME: 14:00
LOCAL: Auditório IB - formato híbrido
TITLE:

"Fungal communities in the phyllosphere of Cerrado woody species: Effects of nutrient addition to the soil".

KEY WORDS:

Epiphytic Fungi, Mycobiome, Secondary Metabolites, Ecometabolomics, Antifungal, Tropical Savanna, Eutrophication, Fertilization

PAGES: 160
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Fungi found in the phyllosphere play a crucial role in producing metabolites, acquiring nutrients, and protecting their hosts against pathogens. However, studies on phyllosphere microorganisms have received less attention. Understanding how soil changes and associated microbial communities modify the production of metabolites in a species is crucial for clarifying natural system interactions and the potential consequences of anthropogenic changes, such as increased nutrient deposition, on microorganism-plant interactions. Furthermore, changes in the soil can alter the chemical diversity of tree species and impact the production of antimicrobial compounds. Thus, the objective of this work is to describe and characterize the community of phyllosphere fungi of two woody species from the Cerrado and understand how changes in the soil can interfere with the phyllosphere community, the metabolites produced by plant species and the potential effects of substances for antifungal use. This work was carried out in an area of cerrado sensu stricto, where a soil fertilization experiment has been carried out since 1998 (IBGE Ecological Reserve). Experimental treatments include addition of nitrogen (N), phosphorus (P), nitrogen + phosphorus (NP) and liming (Ca). Two common woody species from the Cerrado were evaluated: Styrax ferrugineus and Ouratea hexasperma. In chapter 1, the fungal community was described for all treatments of both species through phyllosphere eDNA sequencing. In chapter 2, a metabolomic analysis of the leaves of S. ferrugineus was carried out and a correlation was made between the metabolites found and the fungi that inhabit the phyllosphere. Finally, in chapter 3, extracts from S. ferrugineus leaves were tested in biological assays against 4 species of phytopathogenic fungi (Botrytis sp., Colletotrichum sp., Corynespora sp. and Fusarium sp.) of economic importance for agriculture. The results reveal the predominance of the phylum Ascomycota in the phyllosphere of both species, regardless of treatments, and a greater abundance of the classes Dothideomycetes, Eurotiomycetes and Sordariomycetes. There was no great difference in the alpha diversity of both woody species, however, the beta diversity analyzes of S. ferrugineus indicate a significant change in the phyllosphere communities. Such changes were not related to the elemental content of the leaves and seem to be more related to the anatomical changes that the nutrient addition treatments promoted. Metabolomics leaves of S. ferrugineus were not strongly affected by treatments, with only 3.8% of detected ions varying significantly. Spearman's correlation analysis demonstrates that there is a relationship between the detected ions and the different orders of phyllosphere fungi, with very significant correlations in relation to the most diverse classes of fungi. These results are a first indication that the interactions of species that remain in the system after soil eutrophication are also affected and can have a significant impact on the dynamics between species. Extracts from S. ferrugineus leaves showed potential antifungal action only on Botrytis, with extracts from the liming treatment showing an inhibition greater than 70%. Future studies are necessary to isolate the substance(s) and elucidate their mechanism of action, for possible agricultural application.

COMMITTEE MEMBERS:
Externo ao Programa - 1703888 - HELSON MARIO MARTINS DO VALE - UnBExterna à Instituição - LEONOR COSTA MAIA - UFPE
Presidente - 1122706 - MERCEDES MARIA DA CUNHA BUSTAMANTE
Externo à Instituição - NORBERTO PEPORINE LOPES - USP
Interno - 1147029 - PEDRO HENRIQUE BRUM TOGNI