Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 538084
Title Transcriptome analysis reveals the genetic foundation for the dynamics of starch and lipid production in Ettlia oleoabundans
Author(s) Sturme, Mark H.J.; Gong, Yanhai; Heinrich, Josué Miguel; Klok, Anne J.; Eggink, Gerrit; Wang, Dongmei; Xu, Jian; Wijffels, Rene H.
Source Algal Research 33 (2018). - ISSN 2211-9264 - p. 142 - 155.
DOI https://doi.org/10.1016/j.algal.2018.05.004
Department(s) Bioprocess Engineering
Biobased Products
FBR Bioconversion
VLAG
Publication type Refereed Article in a scientific journal
Publication year 2018
Keyword(s) Carbon-partitioning - Lipids - Microalgae - Nitrogen starvation - Starch - Transcriptome
Abstract

The oleaginous microalga Ettlia oleoabundans accumulates both starch and lipids to high levels under stress conditions such as nitrogen starvation (N−). To steer biosynthesis towards starch or lipids only, it is important to understand the regulatory mechanisms involved. Here physiological and transcriptional changes under nitrogen starvation were analysed in controlled flat-panel photobioreactors at both short and long time-scales. Starch accumulation was transient and occurred rapidly within 24 h upon starvation, while lipid accumulation was gradual and reached a maximum after 4 days. The major fraction of accumulated lipids was composed of de novo synthesized neutral lipids - triacylglycerides (TAG) - and was characterized by a decreased composition of the polyunsaturated fatty acids (PUFAs) C18:3 and C16:3 and an increased composition of the mono-unsaturated (MUFAs) and saturated (SFAs) fatty acids C18:1/C16:1 and C18:0/C16:0, respectively. RNA-sequencing revealed that starch biosynthesis and degradation genes show different expression dynamics from lipid biosynthesis ones. An immediate rapid increase in starch synthetic transcripts was followed by an increase in starch degrading transcripts and a decrease in the starch synthetic ones. In contrast, increased gene expression for fatty acid and TAG synthesis was initiated later and occurred more gradually. Expression of several fatty acid desaturase (FAD) genes was decreased upon starvation, which corresponds to the observed changes to higher levels of MUFAs and SFAs. Moreover, several homologs of transcription regulators that were implicated in controlling starch and lipid metabolism in other microalgae showed differential gene expression and might be key regulators of starch and lipid metabolism in E. oleoabundans as well. Our data provide insights into the genetic foundation of starch and lipid metabolism in E. oleoabundans under nitrogen starvation and should facilitate metabolic engineering towards tailored strains with desired storage compound composition.

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