Wild Patagonian yeast improve the evolutionary potential of novel interspecific hybrid strains for Lager brewing

Abstract

ABSTRACTLager yeasts are limited to a few strains worldwide, imposing restrictions on flavour and aroma diversity and hindering our understanding of the complex evolutionary mechanisms during yeast domestication. The recent finding of diverseS. eubayanuslineages from Patagonia offers potential for generating new Lager yeasts and obtaining insights into the domestication process. Here, we leverage the natural genetic diversity ofS. eubayanusand expand the Lager yeast repertoire by including three distinct PatagonianS. eubayanuslineages. We used experimental evolution and selection on desirable traits to enhance the fermentation profiles of novelS. cerevisiaexS. eubayanushybrids. Our analyses reveal an intricate interplay of pre-existing diversity, selection on species-specific mitochondria,de-novomutations, and gene copy variations in sugar metabolism genes, resulting in high ethanol production and unique aroma profiles. Hybrids withS. eubayanusmitochondria exhibited greater evolutionary potential and superior fitness post-evolution, analogous to commercial Lager hybrids. Using genome-wide screens of the parental subgenomes, we identified genetic changes inIRA2,SNF3,IMA1andMALXgenes that influence maltose metabolism, and increase glycolytic flux and sugar consumption in the evolved hybrids. Functional validation and transcriptome analyses confirmed increased maltose-related gene expression, influencing grater maltotriose consumption in evolved hybrids. This study demonstrates the potential for generating industrially viable Lager yeast hybrids from wild Patagonian strains. Our hybridization, evolution, and mitochondrial selection approach produced hybrids with high fermentation capacity, expands Lager beer brewing options, and deepens our knowledge of Lager yeast domestication.