| 论文摘要： |
Astaxanthin, a potent antioxidant carotenoid, is primarily synthesized by the microalga Haematococcus pluvialis (H. pluvialis) and has widespread applications in the nutraceutical, pharmaceutical, and aquaculture industries. In this study, we employed a tandem mass tag (TMT)-based quantitative proteomics approach to investigate the metabolic and regulatory mechanisms underlying astaxanthin biosynthesis in H. pluvialis under weak light stress conditions. Microscopic observation revealed that H. pluvialis retained its green motile morphology while progressively accumulating astaxanthin (0.22 % of dry weight by 48 h) under weak light stress conditions, without compromising growth Proteomic analysis identified 3, 57, and 311 differentially expressed proteins (DEPs) at 12, 24, and 48 h, respectively, highlighting dynamic shifts in lipid metabolism and energy production, and notably the upregulation of proteins involved in both lipid and carotenoid biosynthesis. Three DEPs-farnesyl pyrophosphotransferase (FDFT1), isocitrate dehydrogenase (IDH), and dihydropyrimidine dehydrogenase (DPD)- were selected to assess their contribution to astaxanthin biosynthesis based on expression trends and biological relevance. Due to the difficulty of genetic manipulation in H. pluvialis, heterologous expression was conducted in an engineered Escherichia coli (BW-ASTA) strain producing free astaxanthin. FDFT1 and IDH enhanced astaxanthin yields by 5.0-fold and 1.6-fold, respectively, while DPD showed no significant effect. These findings reveal proteome-level adaptations in H. pluvialis under weak light stress conditions and identify candidate genes for metabolic engineering of astaxanthin biosynthesis, laying groundwork for the development of sustainable, industrial-scale production strategies production. |
