High-throughput insertional mutagenesis reveals novel targets for enhancing lipid accumulation in Nannochloropsis oceanica

The microalga Nannochloropsis oceanica is considered a promising platform for the sustainable production of high-value lipids and biofuel feedstocks. However, current lipid yields of N. oceanica are too low for economic feasibility. Gaining fundamental insights into the lipid metabolism of N. oceani...

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Bibliographic Details
Published in:Metabolic engineering 2021-07, Vol.66, p.239-258
Main Authors: Südfeld, Christian, Hubáček, Michal, Figueiredo, Daniel, Naduthodi, Mihris I.S., van der Oost, John, Wijffels, René H., Barbosa, Maria J., D'Adamo, Sarah
Format: Article
Language:English
Subjects:
APETALA2
FACS
Insertional mutagenesis
Microalgae
Nannochloropsis
Neutral lipid content
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Summary:The microalga Nannochloropsis oceanica is considered a promising platform for the sustainable production of high-value lipids and biofuel feedstocks. However, current lipid yields of N. oceanica are too low for economic feasibility. Gaining fundamental insights into the lipid metabolism of N. oceanica could open up various possibilities for the optimization of this species through genetic engineering. Therefore, the aim of this study was to discover novel genes associated with an elevated neutral lipid content. We constructed an insertional mutagenesis library of N. oceanica, selected high lipid mutants by five rounds of fluorescence-activated cell sorting, and identified disrupted genes using a novel implementation of a rapid genotyping procedure. One particularly promising mutant (HLM23) was disrupted in a putative APETALA2-like transcription factor gene. HLM23 showed a 40%-increased neutral lipid content, increased photosynthetic performance, and no growth impairment. Furthermore, transcriptome analysis revealed an upregulation of genes related to plastidial fatty acid biosynthesis, glycolysis and the Calvin-Benson-Bassham cycle in HLM23. Insights gained in this work can be used in future genetic engineering strategies for increased lipid productivity of Nannochloropsis. •Insertional mutagenesis reveals lipid-associated genes in Nannochloropsis oceanica.•N. oceanica transcription factor NO06G03670 resembles APETALA2 like proteins of plants.•NO06G03670 knockout (KO) increased neutral lipid content without compromising growth.•KO mutant showed upregulation of glycolysis, fatty acid synthesis and CBB cycle genes.
ISSN:1096-7176
1096-7184
DOI:10.1016/j.ymben.2021.04.012