Genotypic Diversity of Hanseniaspora opuntiae Strains Isolated from Spontaneously Fermented Grape Must and Wine

Background and goals Non-Saccharomyces yeasts are dominant during the early stages of alcoholic fermentation of grape must and play an essential role in the production of favorable organoleptic traits in the final wine. Identifying indigenous non-Saccharomyces yeasts for use as starter cultures in co-inoculation or sequential inoculation with Saccharomyces cerevisiae is an effective approach to producing wine with desirable characteristics.

Methods and key findings In this study, musts were collected during spontaneous fermentation of wine produced from two red grape varieties, Kalecik Karası and Öküzgözü. Restriction fragment length polymorphism analysis was used to determine the composition of Hanseniaspora species found in the musts. The results agreed with those from an internal transcribed spacer sequencing analysis. Furthermore, phylogenetic connections among strains of Hanseniaspora opuntiae were explored through random amplified polymorphic DNA (RAPD)-PCR. Four primers were used to investigate the effect of grape cultivation regions on the distribution of H. opuntiae strains. Cluster analysis of RAPD-PCR fingerprints revealed the presence of four distinct groups within the 21 examined strains. Of the primers, the M13 primer had the most discriminatory power for genotyping the H. opuntiae isolates. Statistical analysis of similarities confirmed the differentiation in strain richness among the clusters revealed by analysis with the unweighted pair-group method with arithmetic average. The correlation between biochemical traits and genomic results was explored using biochemical assessments of alcohol tolerance and sulfur dioxide resistance.

Conclusions and significance This study highlights the significance of exploring the genetic diversity of indigenous non-Saccharomyces yeasts, particularly H. opuntiae, in winemaking. Understanding the diversity of wild yeast populations provides valuable information for the development of strategies to optimize wine production, ultimately leading to wines with superior characteristics and sensory profiles.