Abstract: To elucidate the mechanism of glutathione (GSH) biosynthesis by Hansenula polymorpha DL-1 (HP-DL-1) exposed to Na2SeO3, we examined the differentially expressed genes (DEGs) in yeast cells treated and not treated with Na2SeO3 using a combination of transcriptomic sequencing and bioinformatic methods. The results showed that 60 μmol/L Na2SeO3 was found to be able to increase the GSH yield of yeast cells up to (530.22 ± 9.6) mg/L after 48 h fermentation. A total of 1 254 DEGs was identified in the Na2SeO3-induced group, of which 630 genes were up-regulated, whereas the remaining 624 genes were down-regulated. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated that these DEGs were involved in the cell cycle, mitosis, amino acid biosynthesis, glycolysis, ribosome components and methane, fat, nucleic acid, GSH metabolism pathways. This study provides adequate information for a better understanding of the physiological mechanism of GSH biosynthesis by H. polymorpha, which will provide theoretical support for subsequent molecular improvement for over-production of GSH by engineered strains.

Key words: Hansenula polymorpha; glutathione; sodium selenite; transcriptome; differentially expressed genes