Co-expression of the Na(+)/H(+)-antiporter and H(+)-ATPase genes of the salt-tolerant yeast Zygosaccharomyces rouxii in Saccharomyces cerevisiae.

We cloned two genes from the salt-tolerant yeast Zygosaccharomyces rouxii: ZrSOD2 for the cell membrane Na(+)/H(+)-antiporter and ZrPMA1 for the cell membrane H(+)-ATPase. The products of these genes play cooperative roles in the salt-tolerance of Z. rouxii, and the function of the ZrPMA1 product is regulated at the transcription level. We constructed a yeast expression vector that is able to co-express the ZrSOD2 and ZrPMA1 genes. Single expression of ZrSOD2 was effective in conferring salt-tolerance, and although a slight synergic effect was observed with co-expression of ZrSOD2 and ZrPMA1, the usefulness of this co-expression is likely to be minimal with regard to salt-tolerance.