Glycerolipid characterization and nutrient deprivation-associated changes in the green picoalga Ostreococcus tauri

A - Papers appearing in refereed journals

Degraeve-Guilbault, C., Brehelin, C., Haslam, R. P., Sayanova, O. V., Marie-Luce, G., Jouhet, J. and Corellou, F. 2017. Glycerolipid characterization and nutrient deprivation-associated changes in the green picoalga Ostreococcus tauri. Plant Physiology. 173 (4), pp. 2060-2080.

AuthorsDegraeve-Guilbault, C., Brehelin, C., Haslam, R. P., Sayanova, O. V., Marie-Luce, G., Jouhet, J. and Corellou, F.
Abstract

The picoalga Ostreococcus tauri is a minimal photosynthetic eukaryote that has been used as a model system. O. tauri is known to efficiently produce docosahexaenoic acid (DHA). We provide a comprehensive study of the glycerolipidome of O. tauri and validate this species as model for related picoeukaryotes. O. tauri lipids displayed unique features that combined traits from the green and the chromalveolate lineages. The betaine lipid diacylglyceryl-hydroxymethyl-trimethyl-β-alanine and phosphatidyldimethylpropanethiol, both hallmarks of chromalveolates, were identified as presumed extraplastidial lipids. DHA was confined to these lipids, while plastidial lipids of prokaryotic type were characterized by the overwhelming presence of ω-3 C18 polyunsaturated fatty acids (FAs), 18:5 being restricted to galactolipids. C16:4, an FA typical of green microalgae galactolipids, also was a major component of O. tauri extraplastidial lipids, while the 16:4-coenzyme A (CoA) species was not detected. Triacylglycerols (TAGs) displayed the complete panel of FAs, and many species exhibited combinations of FAs diagnostic for plastidial and extraplastidial lipids. Importantly, under nutrient deprivation, 16:4 and ω-3 C18 polyunsaturated FAs accumulated into de novo synthesized TAGs while DHA-TAG species remained rather stable, indicating an increased contribution of FAs of plastidial origin to TAG synthesis. Nutrient deprivation further severely down-regulated the conversion of 18:3 to 18:4, resulting in obvious inversion of the 18:3/18:4 ratio in plastidial lipids, TAGs, as well as acyl-CoAs. The fine-tuned and dynamic regulation of the 18:3/18:4 ratio suggested an important physiological role of these FAs in photosynthetic membranes. Acyl position in structural and storage lipids together with acyl-CoA analysis further help to determine mechanisms possibly involved in glycerolipid synthesis.

Year of Publication2017
JournalPlant Physiology
Journal citation173 (4), pp. 2060-2080
Digital Object Identifier (DOI)doi:10.1104/pp.16.01467
PubMed ID28235892
PubMed Central IDPMC5373045
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Seeds for Nutrition and Health (DS)
Pilot Algal Lipid Manufacturing in the United Kingdom (PALM-UK)
Output statusPublished
Publication dates
Online29 Mar 2017
Publication process dates
Accepted23 Feb 2017
PublisherAmerican Society of Plant Physiologists (ASPP) Rockville, MD
American Society of Plant Biologists (ASPB)
Copyright licensePublisher copyright
ISSN0032-0889

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