Arsenic uptake and biotransformation mechanisms in Dunaliella salina: Insights into physiological and molecular responses

Abstract

The biomass and premium extracts derived from D. salina possess diverse applications in industries like food, feed, health products, nutrition, pharmaceuticals, and cosmetics. However, D. salina's capacity to absorb and transform heavy metals, notably arsenic, can result in elevated arsenic concentrations in its products. This poses a challenge to large-scale D. salina breeding and introduces potential health risks. The impact of arsenic on D. salina product quality and the specific arsenic forms within its cells remain insufficiently understood. This study explores arsenic uptake and biotransformation mechanisms in D. salina exposed to arsenate (AsV) and arsenite (AsIII). Our findings highlight D. salina's preference for AsV, causing a significant rise in intracellular arsenic compared to AsIII exposure. Lower AsV concentrations facilitate arsenic methylation and organic transformation, influencing compound ratios. AsV triggers differential gene expression, upregulating metabolic pathways, arsenic transporters, and antioxidative defenses. Our results suggest that D. salina efficiently detoxifies arsenic by converting it into organoarsenicals, specifically arsenosugars and arsenicbetaine. This research offers valuable insights into microalgae's physiological and molecular responses to arsenic exposure, providing a foundation for understanding arsenic biotransformation mechanisms and potential applications in the large-scale breeding industry of D. salina.