Elevated Trehalose Levels in Mutants Increase Stress Resistance, Not Lifespan.

The insulin/IGF-1 (insulin-like growth factor 1) signaling mutant recapitulates the dauer metabolic signature-a shift towards lipid and carbohydrate accumulation-which may be linked to its longevity and stress resistance phenotypes. Trehalose, a disaccharide of glucose, is highly upregulated in mutants and it has been linked to proteome stabilization and protection against heat, cold, desiccation, and hypoxia. Earlier studies suggested that elevated trehalose levels can explain up to 43% of the lifespan extension observed in mutants. Here we demonstrate that trehalose accumulation is responsible for increased osmotolerance, and to some degree thermotolerance, rather than longevity in mutants. This indicates that particular stress resistance phenotypes can be uncoupled from longevity.