Diversity and composition of asexual ascomycetes associated with aquatic and terrestrial forest plant debris in Rio Grande do Norte (Brazil) revealed by direct observation

The asexual ascomycetes form a group of microfungi that reproduce by mitosis and are essential in nutrient cycling. These fungi are widely studied worldwide, with the Central and South American regions highlighted as hotspots for new genera and species. In the Tropical Forest of the Brazilian northeast, studies are concentrated in Bahia, Paraiba and Pernambuco states, while they are scarce in Rio Grande do Norte state in the northeastern most corner of the South American continent. Dead leaves and twigs were collected from terrestrial and aquatic environments at two locations in September and November 2020. In the laboratory, 320 batches of substrate samples were washed and stored in humid chambers for 30 days. This approach favors the development of many morphologically identifiable anamorphic fungi which can be detected by direct observation. Forty-one asexual ascomycetes taxa were identified, among these, 23 were identified to species and 18 new records for the Rio Grande do Norte. The diversity of environments and areas was high, while the similarity between environments was low. These results expand the knowledge of the Brazilian mycobiota, in addition to revealing the need for more studies on the diversity of these fungi.

Automated summary

Asexual ascomycetes are microfungi that reproduce by mitosis and play an important role in nutrient cycling. These fungi are widely studied globally, with Central and South American regions being hotspots for new species and genera. In Brazil's northeast, particularly Bahia, Paraiba, and Pernambuco states, research on asexual ascomycetes is concentrated, while studies are scarce in Rio Grande do Norte state. A recent study conducted in northern Brazil identified 41 taxa of asexual ascomycetes, including 18 new records for the Rio Grande do Norte region, highlighting the need for further research on the diversity of these fungi.