Soilborne filamentous fungi in Brazil

Abstract

The Atlantic Rainforest is a Brazilian ecosystem that is being rapidly being destroyed, along with the abiotic and biotic factors present in it. Among the biotic factors, the fungi are found in the soil which, besides being of major importance in terms of ecological niches, also have broad and significant applications in biotechnology. In order to assess the biodiversity of these microorganisms in this type of ecosystem, the Banhado Grande region was chosen at the Jureia-Itatins Ecology Station, in the state of Sao Paulo, Brazil. Within this region, two areas were delimited for study, one covered with natural (primary) vegetation and the other containing vegetation that regenerated following the planting of rice crops, referred to here as secondary. Collection of compound soil samples were taken (depth 0-15 cm) over a period of two and a half years, with the litter first being removed, during dry/cold and humid/hot periods. After sifting the samples, they were appropriately processed using the serial dilution technique to isolate the fungi from the soil. Six different culture media were used, having pHs of 4.5, 7.0 and 9.0. Altogether, 1,211 strains were isolated, divided into the following groups: Hyphomycetes, the most abundant followed by Ascomycetes, Zygomycetes, Coelomycetes, and Oomycetes. From these, 112 species were identified, 8 down to the genus level, and those that did not produce conidia were grouped as Mycelia sterilia. Among the strains, 67 were cellulolytic, 32 originated solely in soil under natural vegetation, and 26 originated solely in soil under secondary vegetation.