It has long been thought that the biosynthesis of trehalose, a sugar present in all kingdoms, is absent from the vast majority of higher plants. However, recent experiments have indicated that genes from Arabidopsis are able to complement yeast strains deficient in trehalose metabolism. In yeast, trehalose has been suggested as a regulatory component in the control of glycolytic flux and in a variety of stress survival strategies. Thus, the occurrence of complimentary genes in Arabidopsis and yeast might lead to the development of strategies and applications for improvement of crop plants.