Südfeld Christian, Hubáček Michal, Figueiredo Daniel, Naduthodi Mihris I S, van der Oost John, Wijffels René H, Barbosa Maria J, D'Adamo Sarah
Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA, Wageningen, Netherlands.
Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA, Wageningen, Netherlands.
Metab Eng. 2021 Jul;66:239-258. doi: 10.1016/j.ymben.2021.04.012. Epub 2021 May 7.
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.
微藻海洋微拟球藻被认为是可持续生产高价值脂质和生物燃料原料的一个有前景的平台。然而，目前海洋微拟球藻的脂质产量过低，缺乏经济可行性。深入了解海洋微拟球藻的脂质代谢，可为通过基因工程优化该物种开辟多种可能性。因此，本研究的目的是发现与中性脂质含量升高相关的新基因。我们构建了海洋微拟球藻的插入诱变文库，通过五轮荧光激活细胞分选筛选出高脂质突变体，并使用一种快速基因分型程序的新方法鉴定被破坏的基因。一个特别有前景的突变体（HLM23）在一个假定的类APETALA2转录因子基因中发生了突变。HLM23的中性脂质含量增加了40%，光合性能提高，且生长未受损害。此外，转录组分析显示HLM23中与质体脂肪酸生物合成、糖酵解和卡尔文-本森-巴斯姆循环相关的基因上调。本研究获得的见解可用于未来提高微拟球藻脂质生产力的基因工程策略。
