ANALYSIS OF CELL-WALL CARBOHYDRATES (NEURAL SUGARS) FROM ASCOMYCETOU AND BASIDIOMYCETOUS YEASTS WITH AND WITHOUT DERIVATIZATION

The presence or absence of fucose, galactose, rhamnose, and xylose as well as the ratio of glucose to mannose after hydrolysis of purified y east cell walls are valuable characters to assign yeasts or yeast stat es of Ascomycetes and Basidiomycetes phylogenetically. The coupling of pellicular anion-exchange resins (Dionex CarboPac PA-1) with pulsed a mperometric detection provides a simple, quick, selective, and sensiti ve method for the analysis of yeast cell wall carbohydrates. Phragmoba sidial smut fungi of monocotyledonous (Ustilago s. str., Sporisorium) and dicotyledonous (Microbotryum, Sphacelotheca) host plants cluster i n two different, phylogenetically distinct yeast types, the Microbotry um type and the Ustilago type. In contrast, all smut fungi with simple holobasidia (Entyloma, Melanotaenium) from monocots and dicots invest igated so far, exhibit a cell wall carbohydrate spectrum characteristi c for the Ustilago type. Ustilentyloma fluitans, although a phragmobas idial smut fungus on grasses, whose smut spores and parasitic symptoms resemble Entyloma species, display the neutral sugar pattern of the M icrobotryum type. The close phylogenetic relationship between the Grap hiolales, Ustilaginales s. str. (phragmobasidial smuts of monocots), a nd Exobasidiales was substantiated further by additional strains. The presence of xylose and balanced amounts of glucose and mannose is char acteristic for yeast states of the Dacrymycetaceae. The production of extracellular amyloid compounds (EAC) as well as the cell wall carbohy drate pattern point to a Tremella type affinity of A tractogloea still ata, Itersonilia perplexans, and Sterigmalosporidium polymorphum. A me iosporangial evolution starting from coccal yeast basidia (Sterigmatos poridium) via transversely (auricularioid) septate (Atractogloea) to l ongitudinally divided phragmobasidia (Tremella) and simple holobasidia (Cystofilobasidium) was substantiated further within the Tremella typ e. The complex holobasidia (Collybia) of the Homobasidiomycetes evolve d polyphyletically from longitudinally septate phragmobasidia via part ially divided holobasidia (Carcinomyces). On the basis of the cell wal l carbohydrate composition of approximately 250 yeasts and yeast stage s of Ascomycetes and Basidiomycetes, seven distinct yeast types are de scribed and interpreted phylogenetically.