Molecular and cellular mechanisms of neutral lipid accumulation in diatom following nitrogen deprivation

Biotechnology for Biofuels

Zhi-Kai Yang¹  Ying-Fang Niu¹  Yu-Han Ma¹  Jiao Xue¹  Meng-Han Zhang¹  Wei-Dong Yang¹  Jie-Sheng Liu¹  Song-Hui Lu¹  Yuanfang Guan²  Hong-Ye Li¹ 

[1] Key Laboratory of Eutrophication and Prevention of Red Tide of Guangdong Higher Education Institute, College of Life Science, Jinan University, Guangzhou, 510632, China

[2] Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, 48109, United States of America

关键词: Transcriptomics;    Membrane remodeling;    Lipid;    Nitrogen deprivation;    Microalga;   

Others  :  798063
DOI  :  10.1186/1754-6834-6-67

 received in 2012-09-25, accepted in 2013-05-01,  发布年份 2013

【 摘 要 】

Background

Nitrogen limitation can induce neutral lipid accumulation in microalgae, as well as inhibiting their growth. Therefore, to obtain cultures with both high biomass and high lipid contents, and explore the lipid accumulation mechanisms, we implemented nitrogen deprivation in a model diatom Phaeodactylum tricornutum at late exponential phase.

Results

Neutral lipid contents per cell subsequently increased 2.4-fold, both the number and total volume of oil bodies increased markedly, and cell density rose slightly. Transcriptional profile analyzed by RNA-Seq showed that expression levels of 1213 genes (including key carbon fixation, TCA cycle, glycerolipid metabolism and nitrogen assimilation genes) increased, with a false discovery rate cut-off of 0.001, under N deprivation. However, most light harvesting complex genes were down-regulated, extensive degradation of chloroplast membranes was observed under an electron microscope, and photosynthetic efficiency declined. Further identification of lipid classes showed that levels of MGDG and DGDG, the main lipid components of chloroplast membranes, dramatically decreased and triacylglycerol (TAG) levels significantly rose, indicating that intracellular membrane remodeling substantially contributed to the neutral lipid accumulation.

Conclusions

Our findings shed light on the molecular mechanisms of neutral lipid accumulation and the key genes involved in lipid metabolism in diatoms. They also provide indications of possible strategies for improving microalgal biodiesel production.

【 授权许可】

   
2013 Yang et al.; licensee BioMed Central Ltd.

【 图 表 】

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