Abstract
Glucosylceramides (GlcCers) are major glycolipids in plasma membranes and tonoplasts. The genome-wide studies on a glycosyltransferase gene family in animal, plant, fungal, and bacterial origin have revealed that plant GlcCers may be synthesized by glucosylceramide synthase (GCS) (UDP-glucose:ceramide glucosyltransferase). However, the genes for plant GCS were poorly reported; only from cotton. During the initial stages of our studies, even when an Arabidopsis cDNA homologous to a cotton GCS gene was expressed in Saccharomyces cerevisiae, such transformants failed to synthesize GlcCers, which might provide some clue to the mechanism of the glucosylation to ceramides. To overcome the difficulty of the functional analysis of Arabidopsis GCS genes, we currently constructed mutants lacking GlcCers in yeast Kluyveromyces lactis. Here we will discuss the function of glycosyltransferase genes in Arabidopsis.
