Temperature Adaptation Markedly Determines Evolution within the GenusSaccharomyces

Abstract

ABSTRACTThe present study uses a mathematical-empirical approach to estimate the cardinal growth temperature parameters (Tmin, the temperature below which growth is no longer observed;Topt, the temperature at which the μmaxequals its optimal value; μopt, the optimal value of μmax; andTmax, the temperature above which no growth occurs) of 27 yeast strains belonging to differentSaccharomycesand non-Saccharomycesspecies.S. cerevisiaewas the yeast best adapted to grow at high temperatures within theSaccharomycesgenus, with the highest optimum (32.3°C) and maximum (45.4°C) growth temperatures. On the other hand,S. kudriavzeviiandS. bayanusvar.uvarumshowed the lowest optimum (23.6 and 26.2°C) and maximum (36.8 and 38.4°C) growth temperatures, respectively, confirming that both species are more psychrophilic thanS. cerevisiae. The remainingSaccharomycesspecies (S. paradoxus,S. mikatae,S. arboricolus, andS. cariocanus) showed intermediate responses. With respect to the minimum temperature which supported growth, this parameter ranged from 1.3 (S. cariocanus) to 4.3°C (S. kudriavzevii). We also tested whether these physiological traits were correlated with the phylogeny, which was accomplished by means of a statistical orthogram method. The analysis suggested that the most important shift in the adaptation to grow at higher temperatures occurred in theSaccharomycesgenus after the divergence of theS. arboricolus,S. mikatae,S. cariocanus,S. paradoxus, andS. cerevisiaelineages from theS. kudriavzeviiandS. bayanusvar.uvarumlineages. Finally, our mathematical models suggest that temperature may also play an important role in the imposition ofS. cerevisiaeversus non-Saccharomycesspecies during wine fermentation.