Draft genome sequence of Candida versatilis and osmotolerance analysis in soy sauce fermentation

The salt-tolerant yeast strain Candida versatilis is usually added to high-salt, liquid-state soy sauce fermentation. The genome of C. versatilis was sequenced in our previous study but the reason for its high-osmolarity ability was not clear.

The 9.7 Mbp genome of C. versatilis contained 4711 CDS. Candida versatilis was the closest to another yeast, Zygosaccharomyces rouxii, added to soy sauce fermentation. The protein sequence of the whole genome was divided into 4338 groups, accounting for 92.1% of all the predicted protein of C. versatilis using OrthoMCL. Mitogen-activated protein kinase (MAPK) signal pathways, including high osmolarity and cell integrity, were predicted and proved by investigating the expression changes of the key genes CvHOG1, CvGPD1, and CvFPS1 in a high osmotic environment and by testing the variations of intracellular glycerol and extracellular glycerol.

Candida versatilis exhibited strong osmotolerance because it could synthesize intracellular glycerol and absorb glycerol from the environment cooperated with the shut down of glycerol efflux channel in membrane. © 2018 Society of Chemical Industry.