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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Mycotoxin Prevention and Applied Microbiology Research » Research » Publications at this Location » Publication #339317
Title: Genome sequence and physiological analysis of Yamadazyma laniorum f.a. sp. nov. and a reevaluation of the apocryphal xylose fermentation of its sister species, Candida tenuis

Author
item HAASE, MAX A. - University Of Wisconsin
item KOMINEK, JACEK - University Of Wisconsin
item LANGDON, QUINN - University Of Wisconsin
item Kurtzman, Cletus
item HITTINGER, CHRIS - University Of Wisconsin

Submitted to: Federation of European Microbiological Societies Yeast Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2017
Publication Date: 5/1/2017
Citation: Haase, M.A.B., Kominek, J., Langdon, Q.K., Kurtzman, C.P., Hittinger, C.T. 2017. Genome sequence and physiological analysis of Yamadazyma laniorum f.a. sp. nov. and a reevaluation of the apocryphal xylose fermentation of its sister species, Candida tenuis. Federation Of European Microbiological Societies Yeast Research. 17(3):fox019.

Interpretive Summary: Xylose fermentation is a rare trait in yeasts, but it is immensely important to the cellulosic biofuel industry. Candida tenuis has been reported to be one of the few known yeasts to ferment D-xylose. In this study, we report the isolation of two strains representing a closely related species of Candida tenuis. Differentiation of the novel species was based on selected gene sequence analyses as well as whole genome sequence analyses of 32 yeast species. Analysis of genome sequences and physiology suggested the genetic basis of a number of traits, including lactose metabolism, is due to the loss of genes encoding lactose permease and beta-galactosidase. Surprisingly, physiological characterization revealed that neither the type strain of C. tenuis nor the novel species fermented xylose. We reexamined three xylose-fermenting strains previously identified as C. tenuis and found that these strains belong to the genus Scheffersomyces and are not C. tenuis. We propose the name Yamadazyma laniorum sp. nov. for the new strains and propose the transfer of Candida tenuis to the genus Yamadazyma as Yamadazyma tenuis comb. nov. Finally, we conclude that C. tenuis is not a xylose-fermenting species, which clarifies the distribution among yeasts of this rare and biotechnologically important metabolic trait.

Technical Abstract: Xylose fermentation is a rare trait that is immensely important to the cellulosic biofuel industry, and Candida tenuis is one of the few yeasts that has been reported with this trait. Here we report the isolation of two strains representing a candidate sister species to C. tenuis. Integrated analysis of genome sequence and physiology suggested the genetic basis of a number of traits, including variation between the novel species and C. tenuis in lactose metabolism due to the loss of genes encoding lactose permease and ß-galactosidase in the former. Surprisingly, physiological characterization revealed that neither the type strain of C. tenuis nor this novel species fermented xylose in traditional assays. We reexamined three xylose-fermenting strains previously identified as C. tenuis and found that these strains belong to the genus Scheffersomyces and are not C. tenuis. We propose Yamadazyma laniorum f.a. sp. nov. to accommodate our new strains and designate its type strain as yHMH7 (=CBS 14780 = NRRL Y-63967T). Furthermore, we propose the transfer of Candida tenuis to the genus Yamadazyma as Yamadazyma tenuis comb. nov. This approach provides a roadmap for how integrated genome sequence and physiological analysis can yield insight into the mechanisms that generate yeast biodiversity.