Antioxidant System Response of Yarrowia lipolytica Cells Under Oxidative Stress

Eukaryotic cells respond to oxidative stress (OS), a physiological condition characterized by the accumulation of reactive oxygen species (ROS), through various protective mechanisms. The antioxidant defense system (ADS) is activated either by post-translational modifications of pre-existing proteins or through the induction of gene expression. These mechanisms protect cellular biomolecules against ROS damage. Although extensive research has been conducted in different species, there is limited information regarding the specific response of <i>Yarrowia lipolytica</i> to OS. This study aims to elucidate the molecular mechanisms by which <i>Y. lipolytica</i> responds to OS by analyzing the expression of genes encoding enzymes involved in antioxidant response, such as superoxide dismutase (Sod), catalase (Cat), and glutathione peroxidase (Gpx). The <i>Y. lipolytica</i> genome contains three <i>CAT</i> genes, one <i>SOD</i> gene, one copper chaperone for Sod (<i>CCS</i>) gene, and one <i>GPX</i> gene. The expression profiles of these genes were assessed in <i>Y. lipolytica</i> cells exposed to H₂O₂ [5 mM] over time. All genes reached their maximal expression within the first 15 min of exposure. Comparative analysis between young and aged <i>Y. lipolytica</i> cells subjected to OS revealed that young cells exhibited higher expression levels for all genes, with <i>CAT3</i> and <i>SOD</i> showing the highest expression values. These findings suggest that the enzymes encoded by these genes play a crucial role in the antioxidant response of this species. To our knowledge, this is the first study demonstrating that the ADS in <i>Y. lipolytica</i> is regulated at the transcriptional level.