Impact of plant cell wall derived sugars on transcriptional and post-transcriptional control in Saccharomyces cerevisiae

Saccharomyces cerevisiae cannot metabolize non-glucose sugars including cellobiose, xylose, xylodextrins in nature, which are prevalent in plant cell wall. Here, one engineered S. cerevisiae strain, which expresses a cellodextrin transporter gene (cdt-1) and an intracellular β-glucosidase gene (codon-optimized gh1-1) from Neurospora crassa; XYL1 (xylose reductase gene), XYL2 (xylitol dehydrogenase gene), and XKS1 (xylulose kinase gene) from Scheffersomyces stipitis, as well as cdt-2 (coding for cellodextrin transporter 2), gh43-2 (coding for β-xylosidase) and gh43-7 (coding for a xylosyl-xylitol-specific β-xylosidase) from N. crassa, can utilize the above non-glucose sugars. We sequenced mRNA from exponential cultures of the engineered S. cerevisiae grown on glucose, cellobiose, xylose or xylodextrins as a single carbon source in both aerobic and anaerobic conditions in biological triplicate. Differences in gene expression between non-glucose sugar and glucose metabolism revealed by RNA deep sequencing indicated that non-glucose sugar metabolism induced mitochondrial activation and reduced amino acid and protein biosynthesis under fermentation conditions. The mRNA levels in glucose-grown, cellobiose-grown, xylose-grown and xylodextrins-grown cells of engineered Saccharomyces cerevisiae in both aerobic and anaerobic conditions were examined by deep sequencing, in triplicate, using Illumina Genome Analyzer-II.