Zygosaccharomyces inter-species hybrids as model of hybrid sterility due to transcriptional network incompatibility.

Mating-type (MAT)-encoded transcriptional factors govern essential industrial traits, such as mating, meiosis ability, shift in ploidy, and adhesive phenotype. In Saccharomyces cerevisiae diploid cells, a1-a2 heterodimer is the master sensor of diploidy, regulating the entry into meiosis under starvation, and the repression of haploid-specific genes (h-sgs) under standard growth conditions. However, how other biotech yeasts govern their life cycle remains poorly understood. The halo-tolerant Zygosaccharomyces rouxii yeasts are important in industrial processes, with applications in food spoilage and fermentation. They exhibit ploidy and karyotype variation, tendency to hybridization, and high diversity in osmostress response. In this study, the Zygosaccharomyces inter-species hybrids were used as model to investigate how the transcriptional network incompatibility affects hybrid sterility.