Project 3.4.1

Understanding Brettanomyces and its adaptation to control measures

Project summary

Brettanomyces yeast cause wine spoilage by producing 4-ethylphenol and 4-ethylguiacol which are responsible for ‘phenolic’, ‘leather’, ‘sweaty’ and ‘medicinal’ aromas (collectively known as ‘Brett’ character). Previous AWRI research has shown that it is possible for sulfite-resistant Brettanomyces strains to evolve and develop even greater levels of sulfite tolerance (when subjected to directed evolution under laboratory conditions), although the genetic basis for this adaptive response remains to be determined.

New molecular tools, including genetic transformation and gene knockout technology have recently been developed, and these now 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 therefore extend the results of previous work by combining a new field survey of Brettanomyces (using both high-throughput phenotyping and whole genome sequencing to determine if further adaptive responses are occurring in the winery environment), with detailed molecular analysis of the genes responsible for resistance to sulfite and the production of the key sensory compounds responsible for Brettanomyces spoilage character (4-ethyl phenol (4-EP) and 4-ethyl guaiacol (4-EG)).