OSMO-REGULATION OF DUNALIELLA TERTIOLECTA AND REGULATORY MECHANISM FOR GLYCEROL SYNTHESIS UNDER OSMOTIC STRESS

Abstract

The eukaryotic and photosynthetic microalgae Dunaliella could respond to osmotic stress by varying the glycerol content. Intracellular glycerol is produced in D. tertiolecta as the osmolyte of osmo-regulation while the abundant extracellular glycerol accumulated could be a stable and effective additional carbon sink for the photosynthetic CO2 assimilation. Cellular behaviors in respond to osmotic stress as well as two key enzymes involved in the regulation of glycerol synthesis were studied in this project to verify the osmo-regulatory mechanisms for glycerol synthesis in D. tertiolecta. As suggested by the findings, D. tertiolecta displayed similar osmo-regulation process to that reported in D. salina. Isolation and characterization of DtPFK indicated that the glycolysis and pentose phosphate pathway had minor contribution to glycerol synthesis under current experimental condition, while DtGPDH, which is responsible for glycerol synthesis, was demonstrated to be regulated by DtMAPK. This study shed light on the molecular basis for D. tertiolecta osmo-regulation.