Temperature and host preferences drive the diversification of Saccharomyces and other yeasts: a survey and the discovery of eight new yeast species.

Compared to its status as an experimental model system and importance to industry, the ecology and genetic diversity of the genus Saccharomyces has received less attention. To investigate systematically the biogeography, community members and habitat of these important yeasts, we isolated and identified nearly 600 yeast strains using sugar-rich enrichment protocols. Isolates were highly diverse and contained representatives of more than 80 species from over 30 genera, including eight novel species that we describe here: Kwoniella betulae f.a. (yHKS285(T) = NRRL Y-63732(T) = CBS 13896(T)), Kwoniella newhampshirensis f.a. (yHKS256(T) = NRRL Y-63731(T) = CBS 13917(T)), Cryptococcus wisconsinensis (yHKS301(T) = NRRL Y-63733(T) = CBS 13895(T)), Cryptococcus tahquamenonensis (yHAB242(T) = NRRL Y-63730(T) = CBS 13897(T)), Kodamaea meredithiae f.a. (yHAB239(T) = NRRL Y-63729(T) = CBS 13899(T)), Blastobotrys buckinghamii (yHAB196(T) = NRRL Y-63727(T) = CBS 13900(T)), Candida sungouii (yHBJ21(T) = NRRL Y-63726(T) = CBS 13907(T)) and Cyberlindnera culbertsonii f.a. (yHAB218(T) = NRRL Y-63728(T) = CBS 13898(T)), spp. nov. Saccharomyces paradoxus was one of the most frequently isolated species and was represented by three genetically distinct lineages in Wisconsin alone. We found a statistically significant association between Quercus (oak) samples and the isolation of S. paradoxus, as well as several novel associations. Variation in temperature preference was widespread across taxonomic ranks and evolutionary timescales. This survey highlights the genetic and taxonomic diversity of yeasts and suggests that host and temperature preferences are major ecological factors.