Phylogenetic Diversity and Extracellular Enzymatic Activities of Yeasts and Yeast-Like Fungi Isolated From Qualea grandiflora (Vochysiaceae) in Cerrado Areas in Northern Minas Gerais, Brazil

Abstract

The Brazilian savannah, Cerrado, a Brazilian phytophysiognomy, is an entire biome that contains as well as other Brazilian ecosystems, a vast biodiversity of microorganisms associated with native plants. Plant species of the Cerrado have attracted attention due to the still limited knowledge regarding their associated microbiota and the possible applications of these microorganisms. Considering that wildflowers are rich reservoirs of yeast diversity, the present study isolated 58 yeast strains from flowers of Qualea grandiflora from two areas of Cerrado sensu stricto in northern Minas Gerais, Brazil. The isolates were evaluated for producing extracellular enzymes in cellulase, amylase, xylanase, protease, tannase, and pectinase tests. We used the YNB agar diffusion method (Difco) supplemented with specific substrates for each enzyme. The strains were identified by analyzing the sequences of the D1/D2 region of the large subunit (26S) rRNA gene and compared to the sequences deposited on GenBank. Fifty-eight strains were isolated, and 14 genera were identified, of which 18 species were yeasts, two species were yeast-like fungi, and three were yeast-like strains to which it was not yet possible to assign the species they belonged to. Among the identified species, the phylum Ascomycota predominated; exceptions were the isolates of the yeast Papiliotrema laurentii and the fungus Anthracocystis heteropogonicola, both belonging to the phylum Basidiomycota. In the enzymatic tests, 44.8% of the strains tested presented an enzymatic profile in solid medium, being capable of producing at least one of the enzymes studied, with the species Coniochaeta rhopalochaeta showing the greatest cellulolytic activity.