Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
Int J Mol Sci. 2022 Sep 5;23(17):10176. doi: 10.3390/ijms231710176.
Microalgal lipids are essential for biofuel and dietary supplement production. Lipid engineering for higher production has been studied for years. However, due to the complexity of lipid metabolism, single-gene engineering gradually encounters bottlenecks. Multiple gene regulation is more beneficial to boosting lipid accumulation and further clarifying the complex regulatory mechanism of lipid biosynthesis in the homeostasis of lipids, carbohydrates, and protein metabolism. Here, three lipid-related genes, DOF, LACS2, and CIS, were co-regulated in by two circles of transformation to overexpress DOF and knock down LACS2 and CIS simultaneously. With the multiple regulations of these genes, the intracellular lipids and FA content increased by 142% and 52%, respectively, compared with CC849, whereas the starch and protein contents decreased by 45% and 24%. Transcriptomic analysis showed that genes in TAG and FA biosynthesis were up-regulated, and genes in starch and protein metabolism were down-regulated. This revealed that more carbon precursor fluxes from starch and protein metabolism were redirected towards lipid synthesis pathways. These results showed that regulating genes in various metabolisms contributed to carbon flux redirection and significantly improved intracellular lipids, demonstrating the potential of multiple gene regulation strategies and providing possible candidates for lipid overproduction in microalgae.
微藻油脂是生物燃料和膳食补充剂生产的关键。多年来，人们一直在研究通过脂质工程来提高产量。然而，由于脂质代谢的复杂性，单一基因工程逐渐遇到了瓶颈。多个基因的调控更有利于促进脂质的积累，并进一步阐明脂质生物合成在脂质、碳水化合物和蛋白质代谢平衡中的复杂调控机制。在这里，通过两轮转化，对三个与脂质相关的基因 DOF、LACS2 和 CIS 进行共调控，以过表达 DOF 并同时敲低 LACS2 和 CIS。通过这些基因的多重调控，与 CC849 相比，细胞内脂质和 FA 含量分别增加了 142%和 52%，而淀粉和蛋白质含量分别减少了 45%和 24%。转录组分析表明，TAG 和 FA 生物合成相关基因上调，淀粉和蛋白质代谢相关基因下调。这表明更多来自淀粉和蛋白质代谢的碳前体流被重新定向到脂质合成途径。这些结果表明，调节各种代谢途径中的基因有助于碳流的重新定向，显著提高了细胞内脂质，证明了多种基因调控策略的潜力，并为微藻中脂质的过量生产提供了可能的候选基因。
