Transcriptional response of Saccharomyces cerevisiae during competition with S. kudriavzevii: Genetic expression variability and accelerated activation.

Transcriptomic studies have become an essential tool to understand the response of yeast to stimuli. The present work analyses the reaction of eight Saccharomyces cerevisiae strains with varying competitive abilities against a competitor (CR85, Saccharomyces kudriavzevii) in co-cultured fermentations. RNA sequencing (RNAseq) was performed at three very early time points after strains coinoculation in fermentation to delimit exactly when S. cerevisiae's response is triggered. A rapid response to its competitor, including activation of the glycolytic pathway, ribosomal metabolism, and nucleotide synthesis, is crucial for the dominance of S. cerevisiae strain in mixed fermentations. Additionaly, the study highlights the necessity of investigating individual yeast strains rather than a holistic species view, as significant variations in responses are observed among strains of the same clade.