Taxonomic Significance of Base Composition of Yeast Dna

Abstract

The base composition of DNA (GC content) from 62 strains of yeasts and yeast-like fungi was studied. They are widely distributed from 26 to 64%. Most species of Saccharomycetaceae exhibited low GC content of 26-42.5%, but Lipomyces starkeyi and Naganishia globosus showed rather high values of 45.5% and 47.5%, respectively.In Cryptococcaceae, the GC content ranged from 30 to 64%. Yeasts belonging to Cryptococcus and Rhodotorula exhibited high GC content of 46-56% and 47.5-64%, respectively.In the genera of Torulopsis, Candida and Trichosporon, GC contents were widely distributed, namely, 34.5-52.5% in Torulopsis, 30-60% in Candida, and 32.5-59% in Trichosporon. Brettanomyces bruxellensis and Kloeckera apiculata exhibited low GC content of 35% and 30%, respectively. Trigonopsis variabilis showed rather a high value of 44%. Sporobolomyces salmonicolor, a ballistosporous yeast, exhibited a high GC content (57%). Of the yeast-like fungi, Tremella fuci formis and Aureobasidium pullulans showed high GC content of 54.5% and 51.5%, respectively.Meanwhile, Dipodascus albidus and Geotrichum candidum exhibited low GC content of 33% and 40.5%, respectively. A phylogenetic relationship between the yeasts exhibiting a high GC content and Heterobasidiomycetes was discussed. A taxonomic significance of urease activity was found to be correlated to the GC content.Since the suggestion of MARMUR et al. (1), the base composition of DNA (GC content) has been considered to be one of the most useful approaches to bacterial taxonomy.However, a little is known of it in yeasts. DNAs of yeasts were analyzed by VISCHER et al. (2), ZAMMENHOF and CHARGAFF (3), SCHILDKRAUT et al. (4), MARMUR and DOTY (5), ROST and VENNER (6), and by TEWARI et al. (7), but these works were restricted to certain species of Saccharomyces and Schizosaccharomyces.From the phylogenetic point of view, STORCK (8) analyzed the DNAs of 30 species of true fungi including yeasts and yeast-like fungi, and concluded that the GC content of fungal DNA appeared to have a taxonomic and phylogenetic significance. The present paper deals with the GC content of 62 strains of yeasts and yeast-like fungi selected from the viewpoint of taxonomy, and discusses the relationship between the yeasts and allied microorganisms on the basis of the GC content and urease activity.The detailed results of the genera 345

Dna Base Composition of the Genus Hansenula

“…This value is similar to other ascosporogenous genera of yeasts (1). Therefore, it is apparent that the knowledge of DNA base ratio gives no advantage for delimitation of the genus Hansenula in the present scheme of yeast taxonomy.…”

“…Cultivation and harvest of yeasts, and isolation of DNA. Methods for cultivation and harvest of yeasts, and that for the isolation of DNA followed the procedures previously reported (1).…”

“…In the previous paper (1), it was shown that the DNA base ratio (GC content) in ascosporogenous yeasts was relatively low, and that the range of distribution was not so large as that of asporogenous yeasts. However, intrageneric variations of the DNA base ratio of the ascosporogenous yeasts were rather large and the genera of this group of yeasts seemed not necessarily to consist of closely related species.…”

Recognition of Yeast Species from Gene Sequence Comparisons

“…From this work, it was seen that ascomycetous yeasts had a nuclear DNA content of ca. 28-50 mol%, whereas basidiomycetous yeasts had a noticeably higher range of 50-70 mol% [1,2]. These studies suggested that strains differing by 1-2 mol% were likely to represent different species, thus providing a means for excluding some strains that were incorrectly assigned to a particular species.…”

An electrophoretic comparison of enzymes of ballistosporogenous yeasts.

“…A close relationship between ballistosporogenous yeasts and some species of the genera Rhodotorula and Cryptococcus has been suggested by various biochemical studies (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). In previous papers the present authors reported that electrophoretic comparison of enzymes was a useful tool to clarify taxonomical relationships among strains of the genera Rhodotorula and Rhodosporidium (15), among strains of the genus Cryptococcus and related microorganisms (16), and between asporogenous yeasts and their supposed ascosporogenous states (17).…”