Understanding brewing trait inheritance inde novolager yeast hybrids

Abstract

ABSTRACTHybridization betweenSaccharomyces cerevisiaeandSaccharomyces eubayanusresulted in the emergence ofS. pastorianus, a crucial yeast for lager fermentation. However, our understanding of hybridization success and hybrid vigour between these two species remains limited due to the scarcity ofS. eubayanusparental strains. Here, we explore hybridization success and the impact of hybridization on fermentation performance and volatile compound profiles in newly formed lager hybrids. By selecting parental candidates spanning a diverse array of lineages from both species, we reveal that the Beer and PB-2 lineages exhibit high rates of hybridization success inS. cerevisiaeandS. eubayanus, respectively. Polyploid hybrids were generated through rare mating techniques, revealing a prevalence of triploids and diploids over tetraploids. Despite the absence of heterosis in fermentative capacity, hybrids displayed phenotypic variability, notably influenced by maltotriose consumption. Interestingly, ploidy levels did not significantly correlate with fermentative capacity, although triploids exhibited greater phenotypic variability. TheS. cerevisiaeparental lineages primarily influenced volatile compound profiles, with significant differences in aroma production. Interestingly, hybrids emerging from the BeerS. cerevisiaeparental lineages exhibited a volatile compound profile resembling the correspondingS. eubayanusparent. This pattern may result from the dominant inheritance of theS. eubayanusaroma profile, as suggested by the over-expression of genes related to alcohol metabolism and acetate synthesis in hybrids including the BeerS. cerevisiaelineage. Our findings suggest complex interactions between parental lineages and hybridization outcomes, highlighting the potential for creating yeasts with distinct brewing traits through hybridization strategies.