The human pathogen Candida albicans is considered an obligate commensal of animals, yet it is occasionally isolated from trees, shrubs, and grass. We generated genome sequence data for three strains of C. albicans that we isolated from oak trees in an ancient wood pasture, and compared these to the genomes of over 200 clinical strains. C. albicans strains from oak are similar to clinical C. albicans in that they are predominantly diploid and can become homozygous at the mating locus through whole-chromosome loss of heterozygosity. Oak strains differed from clinical strains in showing slightly higher levels of heterozygosity genome-wide. Using phylogenomic analyses and in silico chromosome painting, we show that each oak strain is more closely related to strains from humans and other animals than to strains from other oaks. The high genetic diversity of C. albicans from old oaks shows that they can live in this environment for extended periods of time.
Bibliographical noteFunding Information:
We thank Darren Heavens of the Earlham Institute (Norwich, UK) for the low input transposase-enabled whole-genome sequencing of the oak and type strains of C. albicans. We also thank Jenna Hamlin, Casey Bergman, Dave Hall and three anonymous reviewers for helpful comments on the manuscript. The work of J.D., C.J.B., A.E., and I.N.R. was supported by the Biotechnology and Biological Sciences Research Council, through a National Capability award to the National Collection of Yeast Cultures (grant number BBS/E/F/00044440 to I.N.R.) and an Institute Strategic Programme award to the Institute of Food Research (grant number BBS/E/F/00044471 to I.N.R.).
© 2019 by the Genetics Society of America.
- Environmental reservoir
- Loss of heterozygosity (LOH)
- Molecular evolution
- Population genomics
- Yeast ecology