RESUMEN
A polyphasic molecular approach was used in order to characterize and taxonomically assign Debaryomyces yeast isolates of different origins. Actin 1 (ACT1) gene sequences coupled with AFLP markers showed that the investigated yeasts belonged to the recently reinstated species D. hansenii, D. fabryi and D. tyrocola. The strain HA1179 was supposed to be a D. hansenii strain with introgressed D. fabryi DNA segments. This strain acquired ribosomal RNA encoding genes (rDNA) and the ACT1 gene from the species D. fabryi and D. hansenii respectively. Comparative sequence analysis of the ACT1 gene, ITS1-5.8S-ITS2 (5.8S-ITSs) and D1/D2 regions, suggested that five strains isolated from a municipal wastewater treatment plant could represent a new taxon of the genus, for which the name Debaryomyces vindobonensis was proposed. The calculated degree of similarity between the AFLP patterns indicated that the strains of D. vindobonensis and the closely related species were separated by the values ï¼0.5. New yeast isolates showed very similar morphological and physiological properties to related Debaryomyces species. They differed notably only by the assimilation of rhamnose and growth at 50% glucose. In contrast to the other species, D. vindobonensis was unable to assimilate starch.
Asunto(s)
Saccharomycetales/clasificación , Saccharomycetales/aislamiento & purificación , Aguas Residuales/microbiología , Actinas/genética , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Datos de Secuencia Molecular , Filogenia , Saccharomycetales/genética , Análisis de Secuencia de ADNRESUMEN
The aim of the present study was to evaluate the autochthonous yeast population during spontaneous fermentations of grape musts in Austrian wine-producing areas. Investigation of genomic and genetic variations among wine yeasts was a first step towards a long-term goal of selecting strains with valuable enological properties typical for this geographical region. An approach, combining sequences of the D1/D2 domain of the 26S rRNA gene and random amplified polymorphic DNA fingerprinting, was used to characterize yeasts at the species level, whereas the differentiation of Saccharomyces strains was accomplished by amplified fragment length polymorphism fingerprinting. At the beginning of fermentation, representatives of nine genera were identified, with Hanseniaspora and Metschnikowia species characterized most frequently. Saccharomyces cerevisiae and Saccharomyces bayanus var. uvarum strains, which were identified throughout the entire fermentation process, showed a high level of genetic diversity. A number of S. cerevisiae strains were common at multiple wineries, but a wide range of strains with characteristic profiles were characterized at individual locations. This biodiversity survey represents a contribution to the investigation and preservation of genetic diversity of biotechnologically relevant yeasts in Austrian wine-making areas.