CONSTRUCTION OF SACCHAROMYCES-CEREVISIAE STRAINS THAT ACCUMULATE RELATIVELY LOW CONCENTRATIONS OF TREHALOSE, AND THEIR APPLICATION IN TESTING THE CONTRIBUTION OF THE DISACCHARIDE TO STRESS TOLERANCE

Genetically related diploid strains of Saccharomyces cerevisiae that accumulate varied amounts of trehalose during starvation for nitrogen have been constructed. Strains that produced > 5% trehalose (dry cell weight) were more tolerant of thermal, or freeze-thaw stresses than strains that produced < 4% trehalose. Thus trehalose appears to play a role in stress tolerance of yeast. The significance of these results is that, for the first time, a series of related, unmutated strains have been used to test the effect of trehalose on thermotolerance. Previous studies employed either heat shock treatment, or mutated strains to provide trehalose variations, and as such the contribution of the disaccharide to stress tolerance could not necessarily be separated from other factors such as heat shock proteins.