title: Lipid droplet synthesis is limited by acetate availability in starchless mutant of Chlamydomonas reinhardtii.
abstract: Phenotypic and genotypic changes in Chlamydomonas reinhardtii BafJ5, a starchless mutant, with respect to lipid metabolism was studied in different trophic states under nitrogen (N) sufficient and limited conditions. Interestingly, cellular lipid content increased linearly with input acetate concentration with highest lipid content (∼42%) under nitrogen limitation and mixotrophic state. RT-qPCR studies indicate that key fatty acid biosynthesis genes are down-regulated under N limitation but not under mixotrophic state, whereas, ACS2, encoding Acetyl-CoA synthetase, and DGTT4, encoding Diacylglycerol O-acyltransferase, are up-regulated under all conditions. These results collectively indicate that acetate is the limiting factor and central molecule in lipid droplet synthesis. The study also provides further evidence of the presence of a chloroplast pathway for triacylglycerol synthesis in microalgae.
authors: Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
authors: Rishiram
authors: R
authors: Ramanan
authors: Byung-Hyuk
authors: BH
authors: Kim
authors: Dae-Hyun
authors: DH
authors: Cho
authors: So-Ra
authors: SR
authors: Ko
authors: Hee-Mock
authors: HM
authors: Oh
authors: Hee-Sik
authors: HS
authors: Kim
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D056804:Biofuels; D016825:Chlamydomonas reinhardtii / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology / Q000378:metabolism; D003066:Coenzyme A Ligases / Q000235:genetics / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism*; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D005227:Fatty Acids / Q000096:biosynthesis* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018613:Microscopy, Confocal; D009154:Mutation; D058458:Nitrogen Cycle; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D019346:Sodium Acetate / Q000378:metabolism*; D013997:Time Factors; D014280:Triglycerides / Q000096:biosynthesis* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D020418:Algal Proteins; D056804:Biofuels; D005227:Fatty Acids; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D014280:Triglycerides; D019346:Sodium Acetate; D051048:Diacylglycerol O-Acyltransferase; D003066:Coenzyme A Ligases