|Middelhoven, Wouter - WAGENINGEN UNIV, NL|
Submitted to: Yeasts International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2000
Publication Date: N/A
Technical Abstract: The question of whether yeasts with similar physiological properties are closely related has been examined using recently published phylogenetic analyses of 26S domain D1/D2 rDNA nucleotide sequences from all currently recognized ascomycetous and basidiomycetous yeasts. Utilization of imidazole as a sole nitrogen source seems to be restricted to genera of the eLipomyces clade. Excretion of starch-like compounds that stain blue with iodine reagent is uncommon among yeasts. These compounds are produced by the ascomycetous Lipomyces clade, by some genera of the 'Archiascomycete' clade and by many basidiomycetous yeasts, most of them of the Tremelloidea. Another example concerns methanol assimilation. Most Candida and Pichia species that are able to assimilate methanol as a sole source of carbon are in a clade delimited by C. nanaspora and C. boidinii. Pichia pastoris represents an exception; this species is phylogenetically well separated from the other clade of methanol assimilating yeasts. Certain yeasts are able to assimilate uric acid and aliphatic amines as sole sources of carbon. Among ascomycetes, these characteristics are shown by species that are also able to assimilate hydrocarbons such as n-hexadecane. Although these species show little phylogenetic homogeneity, species assimilating adenine and some other purines are closely related. Species utilizing adenine/uric acid, glycine, hexadecane, branched chain aliphatics, leucine and isoleucine are generally in the Stephanoascus/Arxula/Blastobotrys clade, although Stephanoascus farinosus and Blastobotrys elegans fail to grow on some of these compounds. However, Candida blankii assimilates many of the preceding compounds, with the exception of adenine, but it appears only distantly related to the Stephanoascus clade.