Genomic scanning of the promoter sequence in osmo/halo-tolerance related QTLs in Zygosaccharomyces rouxii

Zygosaccharomyces rouxii, an osmotic stress-tolerant yeast species is conventionally used in high sugar/saline food supplements and in beverage industries. The genetic basis of phenotypic and fundamental diversity of the species is less understood. In this study, we scanned the promoter region of 50 osmo/halo-tolerant genes in yeast species with special reference to Zygosaccharomyces rouxii in order to understand their distinct regulation during osmo or halo-stress condition. In their promoter region, we have focused on the stress regulatory elements (STREs), repetitive elements, and the transcription factor (TF) binding sites of the genes. These motifs are known to play a key role in the regulation of the transcription of osmo-responsive genes. On analyzing the promoter, we came to know that out of 50 genes analyzed, 18 genes possess STREs, 26 genes harbor tandem repeat sequences and 18 genes have transcription factor binding sites in their promoter region. Herein, we aim to describe how promoters of the osmo/halotolerant genes that possess these STRE elements, tandem repeats, and TF sites are expected to display considerable divergence in the transcriptional activity of the associated gene. We also aim to show that variations in STRE elements, tandem repeat number/length and TFs binding sites alters local nucleosome positioning resulting into differential gene expression. The understanding that would generate from the current study is expected to highly useful in exploitation of yeast in industrial set ups. Acknowledgment of these factors can lead to the development of a better understanding of the physiological mechanisms of tolerance against osmo/halo-stress in the genus Zygosaccharomyces.