Diversidade de espécies dos gêneros Aspergillus, Penicillium e Talaromyces isolados do solo de canga do Quadrilátero Ferrífero

Abstract

The ironstone (canga) is a substrate presenting peculiar characteristics involved in soil formation. It comes from the concentration of ferruginous compounds that put diverse materials together as a result of severe actions from climatic factors on geological material. Such superficially formed iron crusts are typical in the State of Minas Gerais, Brazil, especially in a region known as Iron Quadrangle. The soil is often characterized as a microhabitat mosaic due to its heterogeneity and complexity. Thereby, it is believed to be one of the most important ecosystems regarding the development of microbial populations.However, in canga areas, very little is known about soil fungal communities and its biotechnological attributes. Genera Aspergillus, Penicillium and Talaromyces are common fungi found in soil because they usually have plenty of organic compounds required for their development itself. Furthermore, these organisms are outstanding producers of bioactive molecules frequently used in several areas including the pharmaceutical and food industry, and bioremediation. Hence, the present study aimed to assess the fungal diversity belonging to genera Aspergillus, Penicillium and Talaromyces isolated from soils composing the canga areas in the Iron Quadrangle by using phylogenetic and phenotypic techniques. Ten soil samples were collected in the dry season and other ten samples in the rainy season. Serial dilutions were made into the DG18 and DRBC culture media. Species identification was conducted through morphological and molecular analyses. In total, 2029 fungi from Aspergillus, Penicillium, and Talaromyces were isolated. The dry period presented a larger number of 1275 isolates, while 754 fungi were isolated in the rainy season. About 298 isolates were properly identified as Aspergillus whereas 1731 isolates were related to Penicillium and Talaromyces. Among the unidentified morphotypes, 76 out of 89 were subjected to molecular analyses by using the RPB2, calmodulin, and beta-tubulin gene regions for phylogenetic inference. A total of 35 species were identified including the species A. niger, A. pseudoustus, A. aculetus, A. flavus, P. citrinum, P. janthinellum, P. bilaiae, P. roquerfort, T. angelucus and T. stolli. Inconclusive morphotypes add up to 7 and 34 species remain only in genus classification, of which 9 of them are likely taxonomic novelties such as A. novalimaensis, P. sulcatus, P. minimum, P. asperosus, P. flavosus, P. minasgeraensis, T. rosaceus, T. brasiliensis and T. viscosus. Taking these data into account will provide a greater incentive and stimulate further advancements into the fungal taxonomy field in Minas Gerais, surely enhancing our understanding and knowledge about the biodiversity living in such area.