Yeast as a model to investigate the mitochondrial role in adaptation to dietary fat and calorie surplus

Several research strategies are focused towards understanding the genetic basis and molecular mechanisms that regulate uptake, synthesis, deposition, and mobilization of lipids, in the context of energy homeostasis. Because of the complexity of the problem, major input comes from the use of model systems. The aim of this work was to test the feasibility of using yeast as a model organism for studies related to dietary challenges due to high fat diet and investigate the correlation between FA metabolism and oxidative metabolism. In particular, we ask to what extent the utilization of oleic acid is dependent on mitochondrial function. We studied growth on oleic acid as a sole carbon source, and oleate stress (growth in 2 and 5% oleate) in both laboratory (BY4741 wild-type and Δsco1, Δsco2, Δtgl3, Δtgl4 mutants) and natural strains, comparing the growth phenotypes with the respiratory behaviour for each strain. We confirmed that respiratory competence is fundamental for growth on oleic acid, since the respiratory deficient mutant Δsco1 was unable to grow on oleic acid. In order to understand if the ability to use oleate as carbon source and adapt to high oleate concentrations is a general trait for the Saccharomyces cerevisiae genus, we also studied some natural strains, both diploid and haploid, identifying two meiotic derivatives of SGU90 as unable to grow in oleic acid as a sole carbon source. We investigate some aspects of mitochondrial metabolism in order to gain insights on this new finding