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Understanding Brettanomyces and its adaptation to control measures


Summary

Objective

To generate new knowledge to inform winemakers’ decisions on management of the key spoilage yeast, Brettanomyces.

Background

Despite the implementation of control measures, spoilage by Brettanomyces yeast remains a key quality risk for Australian wine producers. Judicious use of sulfite is one of the key pillars of Brettanomyces control measures, yet data indicates that the Brettanomyces population has adapted to the use of sulfite, with the more sulfite-resistant genotypes becoming dominant among Australian isolates. In addition, sulfite-resistant Brettanomyces strains can evolve and develop even greater levels of sulfite tolerance under laboratory conditions, although the genetic basis for this adaptive response remains to be determined.

Research approach

New molecular tools, such as genetic transformation and gene knockout technology, provide a powerful means to assist in the understanding of the evolution of Brettanomyces both in the laboratory and in the field. This project will combine a new field survey of Brettanomyces with high-throughput phenotyping and whole genome sequencing to determine if further adaptive responses are occurring in the winery environment. Detailed molecular analysis will evaluate both the genes responsible for resistance to sulfite and the production of the key sensory compounds responsible for Brettanomyces spoilage character (4-ethyl phenol and 4-ethyl guaiacol).

Sector benefits

Winery management of Brettanomyces spoilage will be improved by new information on how Brettanomyces evolves resistance to sulfur and how taint characters develop in wine.