Abstract
A novel ethanol hypersensitive mutant, gek1 was isolated from Arabidopsis. The gek1 mutants cannot germinate nor grow in the presence of 0.03% ethanol while they grow normally in the absence of ethanol. The GEK1 gene encodes a novel protein without any known motifs. Interestingly, similarity searches showed that only plants and archaea have the GEK1-related genes.
In order to address the GEK1 function, we tried to see the effect of the overexpression of GEK1 in Arabidopsis, E. coli, S. cerevisiae, and S. pombe. In Arabidopsis, GEK1 overexpression not only recovered the ethanol hypersensitive phenotype but also conferred ethanol tolerance, while GEK1 co-suppression enhanced ethanol sensitivity. On the other hand, the ethanol tolerance of E. coli and yeasts was not affected by GEK1 expression. These results imply that GEK1 protein is involved in a novel ethanol metabolic pathway that is specific to plants and probably to archaea.
