The Saccharomyces cerevisiae strain WYT, deficient in the YAP1 transcription factor, was used in a molecular screen to identify genes from Arabidopsis thaliana that could overcome the oxidative stress-sensitive phenotype of these yeast cells. A cDNA named CEO1 increased the tolerance to oxidative damage caused by tert-butylhydroperoxide of both the Yap1− mutant and the wild-type yeast. Additionally, in Yap1− yeast, CEO1 also induced cross-tolerance to oxidative damage caused by hydrogen peroxide and diamide. CEO1 was assigned as being part of a small gene family that, until now, is exclusively restricted to plants. In Arabidopsis, CEO1 was produced in all organs, especially in roots and stems. By using the yeast two-hybrid system, proteins that specifically interact with CEO1 in yeast were identified, and putative DNA-binding proteins were consistently recovered.
