Glucose Restriction Extends Chronological Lifespan of Budding Yeast by Avoiding Commonly Used Auxotrophic Marker...

Dietary restriction (DR) is a robust lifespan-extending intervention across species. While budding yeast is a fundamental model for DR, results from glucose restriction (GR) often show inconsistencies. This may stem from auxotrophic markers in engineered strains, which can induce abnormal cellular states under starvation. We hypothesized that GR extends chronological lifespan (CLS) primarily by avoiding auxotrophic starvation, thereby allowing cells to better adapt to nutrient depletion. Using non-dividing survival assays for precise nutritional control, we observed that yeast survive significantly longer under carbon starvation than under auxotrophic starvation. The extent of CLS extension was diminished when auxotrophic starvation was absent. Yeast cells under auxotrophic starvation showed decreased resistance to H₂O₂ and increased mutation rate-phenotypes that suggest a failure to enter a robust, quiescent-like state. These findings suggest that auxotrophic starvation may bias not only CLS studies but also broader yeast studies. By reconsidering previous studies with attention to auxotrophic starvation, more meaningful conclusions could emerge. Since auxotrophic nutrients in yeast are analogous to essential amino acids in higher organisms, our findings have broader implications for understanding DR in various species.