The role of trehalose synthesis for the acquisition of thermotolerance in yeast. I. Genetic evidence that trehalose is a thermoprotectant.
In the yeast Saccharomyces cerevisiae, accumulation of the non-reducing disaccharide trehalose is triggered by various stimuli that activate the heat-schock response. Several studies have shown a close correlation between trehalose levels and tolerance to heat stress, suggesting that trehalose may be a protectant which contributes to thermotolerance. In this study, we have examined mutants defective in genes coding for key enzymes involved in trehalose metabolism with respect to the heat-induced and stationary-phase-induced accumulation of trehalose and the acquisition of thermotolerance. Inactivation of either TPS1 or TPS2, encoding subunits of the trehalose-6-phosphate synthase/phosphatase complex, caused an inability to accumulate trehalose upon a mild heat-shock or upon initiation of the stationary phase and significantly reduced the levels of heat-induced and stationary-phase-induced thermotolerance. Deletion of NTH1, the gene coding for the neutral trehalase, resulted in a defect in trehalose mobilization during recovery from a heat shock which was paralleled by an abnormally slow decrease of thermotolerance. Our results provide strong genetic evidence that heat-induced synthesis of trehalose is an important factor for thermotolerance induction. In an accompanying study [Hottiger, T., De Virgilio, C., Hall, M. N., Boller, T. & Wiemken, A. (1993) Eur. J. Biochem. 219, 187-193], we present evidence that the function of heat-induced trehalose accumulation may be to increase the thermal stability of proteins.
De Virgilio
C
C
Botanisches Institut, Universität Basel, Switzerland.
Hottiger
T
T
Dominguez
J
J
Boller
T
T
Wiemken
A
A
D000064:Acclimatization / Q000235:genetics; D005800:Genes, Fungal; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature; D007700:Kinetics; D046911:Macromolecular Substances; D009097:Multienzyme Complexes / Q000096:biosynthesis / Q000235:genetics; D010744:Phosphoric Monoester Hydrolases / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013045:Species Specificity; D013403:Sugar Phosphates / Q000096:biosynthesis; D013997:Time Factors; D014198:Trehalase / Q000096:biosynthesis / Q000235:genetics; D014199:Trehalose / Q000031:analogs & derivatives / Q000096:biosynthesis*
D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D013403:Sugar Phosphates; C082722:trehalose-6-phosphate; D014199:Trehalose; D005964:Glucosyltransferases; C085814:trehalose-6-phosphate synthase-phosphatase complex; D010744:Phosphoric Monoester Hydrolases; D014198:Trehalase