Identification of salt-induced genes of Zygosaccharomyces rouxii by using Saccharomyces cerevisiae GeneFilters.

Yeast GeneFilters containing all Saccharomyces cerevisiae open reading frame (ORF) sequences were used to elucidate gene activity in the osmotolerant yeast Zygosaccharomyces rouxii. Labelled cDNA derived from Z. rouxii was targeted to spotted S. cerevisiae ORFs. Approximately 90-100% homology of Z. rouxii genes with those of S. cerevisiae was required for definitive identification of the cDNAs hybridised to GeneFilter. Hybridised labelled cDNAs were visualised as small spots on the microarray, providing simultaneous information on homologous genes present in Z. rouxii and on their level of gene activity. Cross-hybridisation of the GeneFilters displayed 155 as yet unidentified genes of Z. rouxii hybridising to S. cerevisiae ORFs. From those 155 genes, the activity of 86 genes was influenced as a result of NaCl stress. In comparison with S. cerevisiae 24% of Z. rouxii genes revealed a different transcription behaviour following NaCl stress. All of these genes had no previously defined function in osmotic-stress response in Z. rouxii. Therefore, cross-hybridisation of GeneFilters proves to be an appropriate and straightforward method for screening transcripts in Z. rouxii, which provides an extension of the knowledge of genes present in a yeast genus other than S. cerevisiae.