PHYLOGENETIC ANALYSIS OF THE YEAST COX2 GENE DEKKERA BRUXELLENSIS (Atena Editora)

Abstract

The yeast Dekkera bruxellensis, a teleomorph of Brettanomyces bruxellensis, is the biggest contaminant in distilleries that use sugarcane juice around the world, causing a decrease in ethanol productivity and, consequently, causing losses to the industry. Despite its importance, few genetic studies have been published in the scientific literature. Recent work by our group has shown that this yeast is highly adaptable to the industrial process and we propose a broad genomic analysis to identify the factors responsible for this characteristic. In this study, we evaluated the polymorphism of the COX2 gene, which encodes the cytochrome oxidase II enzyme. The results showed an unexpected greater similarity between the COX2 gene sequences of industrial isolates of D. bruxellensis with its orthologue in D. custersii than with the COX2 sequence of the type strain of D. bruxellensis deposited in GenBank. In addition, we started an in silico comparative analysis of the mitochondrial genome of ascomycete yeasts that have their mitochondrial genome sequenced and deposited in GenBank. This made it possible to construct a physical map of the mitochondrial genome of this clade. Six species with nuclear genomic similarity to D. bruxellensis were subjected to multiple alignments using the computer program Mega v. 4.0. The gene order was defined as L-rRNA COII COIII S-rRNA COI ATPase 8 ATPase 6 Cyt b ATPase 9 Var 1, based on the Saccharomyces cereviseae genome. The CODEHOP and Codon Usage programs were used to refine the design of degenerate primers in order to amplify the orthologous genes of D. bruxellensis. The alignments proved to be representative for primer construction, since a high degree of variability was observed between the syntenic gene sequences of the aforementioned structural genes. These data provide the basis for future analyses of the genetics and evolution of the D. bruxellensis population, which will serve as a basis for establishing correlations between the variability and genetics and the physiological capacities of different industrial strains of D. bruxellensis in search of a better understanding of this yeast's -competitive fitness‖ in the industrial environment.