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SO2 and copper tolerance exhibit an evolutionary trade-off in Saccharomyces cerevisiae


Schmidt, Simon et al. (2023), SO2 and copper tolerance exhibit an evolutionary trade-off in Saccharomyces cerevisiae, Dryad, Dataset,


Copper tolerance and sulfite tolerance are two well-studied phenotypic traits of Saccharomyces cerevisiae. The genetic bases of these traits are derived from allelic expansion at the CUP1 locus and reciprocal translocation at the SSU1 locus, respectively. Previous work identified a negative association between sulfite and copper tolerance in S. cerevisiae wine yeasts. Here we probe the relationship between sulfite and copper tolerance and show that an increase in CUP1 copy number does not impart copper tolerance in all S. cerevisiae wine yeast.  Bulk-segregant QTL analysis was used to identify variance at SSU1 as a causative factor in copper sensitivity, which was verified by reciprocal hemizygosity analysis in a strain carrying 20 copies of CUP1. Transcriptional and proteomic analysis demonstrated that SSU1 over-expression did not suppress CUP1 transcription or constrain protein production but suggested that SSU1 overexpression induced sulfur limitation during exposure to copper. Finally, an SSU1 over-expressing strain exhibited increased sensitivity to moderately elevated copper concentrations in sulfur-limited medium, demonstrating that SSU1 over-expression burdens the sulfate assimilation pathway. Over-expression of MET 3/14/16, genes upstream of H2S production in the sulfate assimilation pathway increased the production of SO2 and H2S but did not improve copper sensitivity in an SSU1 overexpressing background. We conclude that copper and sulfite tolerance are conditional traits in S. cerevisiae and provide evidence of the metabolic basis for their mutual exclusivity. These findings suggest an evolutionary basis for the extreme amplification of CUP1 observed in some yeasts.


A complete description of how the data was collected and the methods used to process it is provided in the associated manuscript.

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Wine Australia, Award: AWRI 1701-3.2.2