Genetic and phenotypic diversity of wine-associated Hanseniaspora species

Abstract The genus Hanseniaspora includes apiculate yeasts commonly found in fruit- and fermentation-associated environments. Their genetic diversity and evolutionary adaptations remain largely unexplored despite their ecological and enological significance. This study investigated the phylogenetic relationships, genome structure, selection patterns, and phenotypic diversity of Hanseniaspora species isolated from wine environments, focusing on Hanseniaspora uvarum , the most abundant non- Saccharomyces yeast in wine fermentation. A total of 151 isolates were sequenced, including long-read genomes for representatives of the main phylogenetic clades. Comparative genomics revealed ancestral chromosomal rearrangements between the slow- (SEL) and fast-evolving (FEL) lineages that could have contributed to their evolutionary split, as well as significant loss of genes associated with mRNA splicing, chromatid segregation and signal recognition particle protein targeting specifically in the FEL lineage. Pangenome analysis within H. uvarum identified extensive copy number variation (CNV), particularly in genes related to xenobiotic tolerance, nutrient transport and metabolism. Investigation into the selective landscape following the FEL/SEL divergence identified diversifying selection in 229 genes in the Hanseniaspora FEL lineage, with significant enrichment in genes within the lysine biosynthetic pathway, suggesting a key role for this amino acid in early FEL adaptation. In H. uvarum , signatures of recent positive selection were detected in genes linked to sulphur assimilation, sterol biosynthesis and glycerol production, indicating potential adaptation to the stresses imposed by grape and wine fermentation. Furthermore, phenotypic screening of 113 isolates revealed substantial intraspecific diversity, with specific species exhibiting enhanced ethanol, osmotic, copper, SO₂, and cold tolerance. These findings provide novel insights into the genomic evolution and functional diversity of Hanseniaspora , expanding our understanding of yeast adaptation to wine fermentation and laying the foundation for targeted gene investigations within this important genus.