Impacts of Nitrogen Starvation on Expression Profiles of Involving Genes in Triacylglycerol Biosynthesis in Chlamydomonas reinhardtii: Towards Microalgal Systems Biotechnology

Objective: Chlamydomonas reinhardtii, the most commonly studied model organism in microalgal kingdom, is known to be a rich lipid producer. Methods: Here, a naturally isolated C. reinhardtii strain was cultivated phototrophically at Erlenmeyer scale in BG11 culture medium. After reaching to stationary growth phase, a nitrogen limited regime with different nitrogen concentrations was applied. Results: Quantitative real time PCR analysis of DGTT1 and DGTT2 genes involved in triacylglycerol accumulation confirmed an increased level of expression for DGTT1 (21.05-fold increase) in nitrogen starvation compared with the nitrogen rich conditions. Besides, DGTT2 transcript levels showed a slight decrease in nitrogen deprivation condition (0.61-fold). Conclusion: The results opened a new way to direct microalgal systems biotechnology towards maximization of triacylglycerol production for green energy production.