Lipid droplet synthesis is limited by acetate availability in starchless mutant of Chlamydomonas reinhardtii

Rishiram Ramanan; Byung-Hyuk Kim; Dae-Hyun Cho; So-Ra Ko; Hee-Mock Oh; Hee-Sik Kim

doi:10.1016/j.febslet.2012.12.020

Lipid droplet synthesis is limited by acetate availability in starchless mutant of Chlamydomonas reinhardtii

FEBS Lett. 2013 Feb 14;587(4):370-7. doi: 10.1016/j.febslet.2012.12.020. Epub 2013 Jan 10.

Authors

Rishiram Ramanan¹, Byung-Hyuk Kim, Dae-Hyun Cho, So-Ra Ko, Hee-Mock Oh, Hee-Sik Kim

Affiliation

¹ Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.

PMID: 23313852
DOI: 10.1016/j.febslet.2012.12.020

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algal Proteins / genetics
Algal Proteins / metabolism
Biofuels
Chlamydomonas reinhardtii / cytology
Chlamydomonas reinhardtii / genetics
Chlamydomonas reinhardtii / growth & development
Chlamydomonas reinhardtii / metabolism*
Chloroplasts / enzymology
Chloroplasts / metabolism
Coenzyme A Ligases / genetics
Coenzyme A Ligases / metabolism
Cytoplasmic Granules / metabolism*
Diacylglycerol O-Acyltransferase / genetics
Diacylglycerol O-Acyltransferase / metabolism
Down-Regulation*
Fatty Acids / biosynthesis*
Fatty Acids / metabolism
Gene Expression Regulation, Plant
Microscopy, Confocal
Mutation*
Nitrogen Cycle
Plant Proteins / genetics
Plant Proteins / metabolism
RNA, Messenger / metabolism
RNA, Plant / metabolism
Sodium Acetate / metabolism*
Time Factors
Triglycerides / biosynthesis*
Triglycerides / metabolism
Up-Regulation

Substances

Algal Proteins
Biofuels
Fatty Acids
Plant Proteins
RNA, Messenger
RNA, Plant
Triglycerides
Sodium Acetate
Diacylglycerol O-Acyltransferase
Coenzyme A Ligases