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 ＜0.5. 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.

This chapter describes the use of some chemotaxonomic approaches used in yeast taxonomy. Its emphasis is placed on FA based lipids and their taxonomic value in yeasts. Emphasis is on cell wall carbohydrate composition, coenzyme Q, electrophoresis of enzymes, and the analysis of fatty acids. For each of these approaches, technical protocols are provided. Coenzyme Q plays a primary role as an essential component of the respiratory electron transport chain of the inner mitochondrial membranes of eukaryotes, and in the plasma membrane of prokaryotes. It is also found in other organelles, and in the plasma membrane of eukaryotes, where it participates in a plasma membrane electron transport system. Furthermore, multiple additional functions of CoQ have been observed. The natural CoQ series encompasses 2,3-dimethoxy-5-methyl-6-polyprenyl-1, 4-benzoquinone nucleus with side chains containing 1 to 12 isoprenoid units. A diverse variety of fungal lipid types occur, including compounds based on long-chain fatty acids (FAs) and those derived from isoprene units such as terpenoid lipids.

The novel genus Holtermanniella is proposed here to accommodate four Cryptococcus species closely related to Holtermannia corniformis that are included in the Holtermannia clade (Basidiomycota, Agaricomycotina). Thus, four novel combinations are proposed: Holtermanniella nyarrowii comb. nov., Holtermanniella festucosa comb. nov., Holtermanniella mycelialis comb. nov. and Holtermanniella wattica comb. nov. In addition, a novel anamorphic yeast species was studied with 15 isolates obtained from different habitats around the world. Analysis of the sequences of the D1/D2 region of their large subunit rDNA showed that the novel species is placed phylogenetically within the Holtermannia clade of the Tremellomycetes (Agaricomycotina, Basidiomycota). PCR fingerprinting and sequencing of ITS1-5.8S-ITS2 showed genetic intraspecific variability among the strains: three groups were formed, which did not correlate with geographical origin or substrate. This novel species, designated the type species of Holtermanniella gen. nov., is described as Holtermanniella takashimae sp. nov.; the type strain is CBS 11174(T) (=HB 982(T) =DBVPG 8012(T)). The order Holtermanniales ord. nov. is proposed here to include Holtermannia (the type genus) and Holtermanniella.

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.

Using a genotypic approach (PCR-fingerprinting, DNA/DNA reassociation, partial sequences of the 26S rDNA gene, complete sequences of the 18S rDNA gene, and sequences of the internal transcribed spacers) five tremelloid yeast isolates from the agarics Asterophora lycoperdoides and A. parasitica were shown to be conspecific with Cryptococcus ramirezgomezianus. It was not possible to distinguish the yeast strains from A. lycoperdoides and A. parasitica using sequences from the intergenic spacer (IGS1). Phylogeny based on the 26S (D1/D2-domain), ITS1-5.8S-ITS2 and complete 18S rDNA demonstrated that C. ramirezgomezianus is closely related to several additional Cryptococcus species (C. humicola, C. longus, C. musci, C. pseudolongus) within the Trichosporonales. A new genus, Asterotremella, and a new family, Asterotremellaceae were introduced for Cryptococcus species clustering within the Trichosporonales having a ubiquinone Q-9. Cryptococcus ramirezgomezianus is a synonym of Asterotremella albida.

A new yeast, Cryptococcus zeae (type strain HB 1207T) is described. Six strains were isolated from corn and pests of corn in Austria. Microsatellite-primed polymerase chain reaction (MSP-PCR) fingerprints showed that the strains are members of the same species. Phylogenetical analyses of domains D1/D2 26S rDNA and ITS 1-5,8S–ITS 2 sequences showed C. zeae to have the closest relationship to C. luteolus. The D1/D2 sequences of C. zeae fit with three Korean Cryptococcus sp. strains (AF459690, AF459691, AF459692). The new species is separable from the closest relative C. luteolus using only two physiological tests.