title: Elevated CO2 improves lipid accumulation by increasing carbon metabolism in Chlorella sorokiniana.
abstract: Supplying microalgae with extra CO2 is a promising means for improving lipid production. The molecular mechanisms involved in lipid accumulation under conditions of elevated CO2, however, remain to be fully elucidated. To understand how elevated CO2 improves lipid production, we performed sequencing of Chlorella sorokiniana LS-2 cellular transcripts during growth and compared transcriptional dynamics of genes involved in carbon flow from CO2 to triacylglycerol. These analyses identified the majority genes of carbohydrate metabolism and lipid biosynthesis pathways in C. sorokiniana LS-2. Under high doses of CO2 , despite down-regulation of most de novo fatty acid biosynthesis genes, genes involved in carbohydrate metabolic pathways including carbon fixation, chloroplastic glycolysis, components of the pyruvate dehydrogenase complex (PDHC) and chloroplastic membrane transporters were upexpressed at the prolonged lipid accumulation phase. The data indicate that lipid production is largely independent of de novo fatty acid synthesis. Elevated CO2 might push cells to channel photosynthetic carbon precursors into fatty acid synthesis pathways, resulting in an increase of overall triacylglycerol generation. In support of this notion, genes involved in triacylglycerol biosynthesis were substantially up-regulated. Thus, elevated CO2 may influence regulatory dynamics and result in increased carbon flow to triacylglycerol, thereby providing a feasible approach to increase lipid production in microalgae.
authors.affiliation: Institute of Biotechnology, Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Zhilan
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Institute of Biotechnology, Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Chen
authors.affiliation: Institute of Biotechnology, Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Jianchang
authors.initials: J
authors.lastname: Du
mesh_terms: D002244:Carbon / Q000378:metabolism*; D057486:Carbon Cycle / Q000187:drug effects; D002245:Carbon Dioxide / Q000494:pharmacology*; D002708:Chlorella / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005227:Fatty Acids / Q000096:biosynthesis; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D063990:Gene Ontology; D006019:Glycolysis / Q000187:drug effects; D050356:Lipid Metabolism / Q000187:drug effects* / Q000235:genetics; D008954:Models, Biological; D058977:Molecular Sequence Annotation; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic / Q000187:drug effects; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D005227:Fatty Acids; D014280:Triglycerides; D002245:Carbon Dioxide; D002244:Carbon
keywords: Chlorella sorokiniana; carbon dioxide; carbon flow; lipid; photosynthesis; transcriptomics