Constructing a wine yeast gene deletion library
Background
Understanding the genetics of wine yeasts is crucial for the strategic development of strains with improved winemaking properties. The study of yeast genetics requires the isolation of variant strains which can be screened for new and interesting properties. In the past, these variants were generated using random mutagenesis approaches. While these techniques can produce yeast strains with desirable properties, the underlying genetic variation which is responsible for the desirable characteristics can be very difficult to identify. In addition, the nature of random mutagenesis does not guarantee that every gene in the genome will be tested. To overcome these limitations, the Wine Yeast Gene Deletion Library (WYGDL) project is systematically assembling a collection of wine yeast strains in which each strain carries a unique and fully-characterised gene variant. Once complete, the collection will contain approximately six thousand strains where each individual variant has lost one of the six thousand genes from the yeast genome.
Progress
Prior to generation of the WYDL, it was necessary to choose a parent wine yeast strain in which the deletion collection would be constructed and the strain AWRI1631 has been developed for this role. This yeast is a stable haploid derived from standard diploid wine yeast. Despite being haploid (i.e. having only one set of chromosomes; most wine yeasts have at least two), the fermentation performance of AWRI1631 was shown by both chemical and sensorial analysis to be comparable to the wine yeast parent strain from which it was derived.
We have obtained DNA cassettes which enable the construction of the library in the AWRI1631 background. Protocols for the high-throughput construction of the library have now been established and the first strains have been produced and characterised.
Highlights
- A haploid wine yeast has been developed as the parent for the WYGDL
- To date almost 2000 strains have been created
Project leader: Dr Paul Chambers
Project team members:
Publications:
995 Borneman, A.R.; Chambers, P.J.; Pretorius, I.S. Yeast systems biology: Modelling the winemaker’s art. TRENDS Biotechnol. 25: 349–355; 2007 (click here to order).
Additional information
To begin construction of the WYDL, collaboration was established with Prof. Charles Boone from the University of Toronto, whose laboratory is currently building a similar deletion library in a laboratory strain.