Functional photosystem I maintains proper energy balance during nitrogen depletion in Chlamydomonas reinhardtii, promoting triacylglycerol accumulation
Nutrient deprivation causes significant stress to the unicellular microalga, Chlamydomonas reinhardtii, which responds by significantly altering its metabolic program. In following N deprivation, the accumulation of starch and triacylglycerols (TAGs) is significantly altered following massive reprogramming of cellular metabolism. One protein that was found to change dramatically and early to this stress was TAB2, a photosystem I (PSI) translation initiation factor, whose transcript and protein levels increased significantly after only 30 min of N deprivation. A detailed physiological and omics-based analysis of an insertional mutant of Chlamydomonas with reduced TAB2 function was conducted to determine what role the functional PSI plays in regulating the cellular response to N deprivation. The tab2 mutant displayed increased acetate assimilation and elevated starch levels during the first 6 h of N deprivation, followed by a shift toward altered amino acid synthesis, reduced TAG content and altered fatty acid profiles. Our results suggested a central role for PSI in controlling cellular metabolism and its implication in regulation of lipid/starch partitioning. Time course analyses of the tab2 mutant versus wild type under N-deprived versus N replete conditions revealed changes in the ATP/NADPH ratio and suggested that TAG biosynthesis may be associated with maintaining the redox statemore »
- Authors:
-
[1];
[2];
[3];
[3];
[3]
- Washington State Univ., Pullman, WA (United States). Inst. of Biological Chemistry; Center for Biotechnology of Borj Cedria (Tunisia)
- Washington State Univ., Pullman, WA (United States). Inst. of Biological Chemistry; Univ. of Southern Mississippi, Hattiesburg, MS (United States). Dept. of Chemistry and Biochemistry
- Washington State Univ., Pullman, WA (United States). Inst. of Biological Chemistry
- Publication Date:
- Grant/Contract Number:
- SC0001295
- Type:
- Accepted Manuscript
- Journal Name:
- Biotechnology for Biofuels
- Additional Journal Information:
- Journal Volume: 10; Journal Issue: 1; Journal ID: ISSN 1754-6834
- Publisher:
- BioMed Central
- Research Org:
- Donald Danforth Plant Science Center, Creve Coeur, MO (United States)
- Sponsoring Org:
- USDOE Office of Science (SC)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 09 BIOMASS FUELS; 60 APPLIED LIFE SCIENCES; Photosystem I; TAB2; Chlamydomonas reinhardtii; Nitrogen depletion; Triacylglycerol; Omics analysis Background
- OSTI Identifier:
- 1368390