Carbon metabolism and transcriptional variation in response to salt stress in the genome shuffled Candida versatilis and a wild-type salt tolerant yeast strain

Abstract

The carbon metabolism and molecular mechanisms of adaptation response when exposed to conditions causing osmotic stress in strains of a wild-type of Candida versatilis (WT) and S3–5 were investigated. The levels of glucose, glycerol and ethanol, as well as transcriptional variation of eight genes that encoded hexokinase (HXK1), mitogen-activated protein kinase (HOG1), glycerol-3-phosphate dehydrogenase (GPD1), aquaglyceroporin (FPS1), pyruvate kinase (PYK1), pyruvate decarboxylase (PDC1), aldehyde dehydrogenase (ALD6), alcohol dehydrogenase (ADH1) in short-term response to salt stress were determined. The results showed that an increase in salt concentration negatively affected glucose consumption and ethanol production in C. versatilis. In contrast, glycerol produced by C. versatilis was positively affected by salt addition. The results showed that HXK1 contributes to rerouting glycolytic flux towards higher glycolysis. The glycerol production generated by S3–5 was higher as compared to WT, which is ascribed to the up-regulated expression of GPD1 and HOG1 genes and down-regulated expression of the FPS1 gene after the initiation of stress treatment.