Introducing a New Breed of Wine Yeast: Interspecific Hybridisation between a Commercial Saccharomyces cerevisiae Wine Yeast and Saccharomyces mikatae

Jennifer R Bellon,Paul J Chambers,Dimitra L Capone,Frank Schmid,Barbara L Dunn,Cecile Fairhead

doi:10.1371/journal.pone.0062053

Abstract

Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.

Highlights

The Saccharomyces sensu stricto complex is a group of closely related yeast species that can mate to form interspecific hybrids
We describe for the first time, the generation of an interspecific hybrid between a commercial S. cerevisiae wine yeast strain and S. mikatae, a species not previously associated with alcoholic fermentation and isolated only from soil and decaying leaf litter [8,9]
The microarray generated from 1600 S. mikatae specific probes and 24,000 S. cerevisiae specific probes further confirmed that this hybrid strain’s genome contained an entire chromosome set from each parent, and appeared to confirm the expected 2:1 S. cerevisiae:S. mikatae ploidy ratio (Figure 2). (Average S. mikatae probe intensity was 2.244 for S. mikatae parent NCYC2888 and 0.935 for hybrid strain CxM1, indicating a reduction of S. mikatae genome in the hybrid strain from diploid to haploid.)

Summary

Introduction

The Saccharomyces sensu stricto complex is a group of closely related yeast species that can mate to form interspecific hybrids. Natural Saccharomyces interspecific hybrids have been isolated from various fermentation environs. A small number of wine yeast and cider yeast strains have been identified as natural interspecific hybrids between the Saccharomyces species, S. cerevisiae, S. bayanus and S. kudriavzevii [1,4,5,6]. We describe for the first time, the generation of an interspecific hybrid between a commercial S. cerevisiae wine yeast strain and S. mikatae, a species not previously associated with alcoholic fermentation and isolated only from soil and decaying leaf litter [8,9]. Members of the Saccharomyces sensu stricto group are considered to be closely related yeast, DNA sequence variation between the most distantly related species within this group corresponds roughly to that between man and mouse [10]

Methods

Results

Conclusion