Differences in environmental stress response between yeasts is consistent with species-specific lifestyles

Defining how organisms respond to environmental change has always been an important step toward understating their adaptive capacity and physiology. Variation in transcription during stress has been widely described in model species, especially in the yeastSaccharomyces cerevisiae, which helped to shape general rules regarding how cells cope with environmental constraints as well as decipher the functions of many genes. Now, comparison of the environmental stress response (ESR) across species is essential to obtain a better insight into the common and species-specific features of stress defense. In this context, we explored the transcriptional landscape of the yeastLachancea kluyveri(formerlySaccharomyces kluyveri) in response to diverse stresses, using RNA-seq. We investigated variation in gene expression and observed a link between genetic plasticity and environmental sensitivity. We identified the ESR genes in this species and compared them to those already found inS. cerevisiae We observed common features between the two species as well as divergence in the regulatory networks involved. Interestingly, some changes were related to differences in species lifestyle. Thus, we were able to decipher how adaptation to stress has evolved among different yeast species. Finally, by analyzing patterns of coexpression, we were able to propose potential biological functions for 42% of genes and furthermore annotate 301 genes for which no function could be assigned by homology. This large dataset allowed for the characterization of the evolution of gene regulation and provides an efficient tool to assess gene function