Miao Congcong, Du Mingting, Du Hongchao, Xu Tao, Wu Shan, Huang Xingwei, Chen Xitao, Lei Suxiang, Xin Yi
School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China.
College of Food Science of Technology, Hainan University, Haikou 570228, China.
Mar Drugs. 2024 Dec 19;22(12):570. doi: 10.3390/md22120570.
The rational dietary ratio of docosahexaenoic acid (DHA) to eicosapentaenoic acid (EPA) can exert neurotrophic and cardiotrophic effects on the human body. The marine microalga produces EPA yet no DHA, and thus, it is considered an ideal EPA-only model to pursue a rational DHA/EPA ratio. In this study, synthetic biological strategy was applied to improve EPA production in . Firstly, to identify promoters and terminators, fifteen genes from were isolated using a transcriptomic approach. Compared to , , and exhibited 1.2~1.3-fold increases in transcription levels. Secondly, to identify EPA-synthesizing modules, putative desaturases (NoFADs) and elongases (NoFAEs) were overexpressed by the and promoters/terminators in . Compared to the wild type (WT), and overexpression resulted in 47.7% and 40.6% increases in EPA yields, respectively. Thirdly, to store EPA in triacylglycerol (TAG), was overexpressed using the promoter/terminator, along with - stacking, forming transgenic line XS521. Compared to WT, TAG-EPA content increased by 154.8% in XS521. Finally, to inhibit TAG-EPA degradation, a TAG lipase-encoding gene was knocked out in XS521, leading to a 49.2-65.3% increase in TAG-EPA content. Our work expands upon EPA-enhancing approaches through synthetic biology in microalgae and potentially crops.
二十二碳六烯酸（DHA）与二十碳五烯酸（EPA）的合理膳食比例可对人体产生神经营养和心脏营养作用。海洋微藻能产生EPA但不产生DHA，因此，它被认为是追求合理DHA/EPA比例的理想仅产EPA模型。在本研究中，应用合成生物学策略提高了微藻中EPA的产量。首先，为了鉴定启动子和终止子，采用转录组学方法从微藻中分离出15个基因。与对照相比，[具体基因1]、[具体基因2]、[具体基因3]和[具体基因4]的转录水平提高了1.2至1.3倍。其次，为了鉴定EPA合成模块，假定的去饱和酶（NoFADs）和延长酶（NoFAEs）通过[具体启动子1]和[具体终止子1]在微藻中过表达。与野生型（WT）相比，[具体基因5]和[具体基因6]的过表达分别使EPA产量提高了47.7%和40.6%。第三，为了将EPA储存于三酰甘油（TAG）中，使用[具体启动子2]和[具体终止子2]过表达[具体基因7]，同时进行[具体基因8]堆叠，形成转基因株系XS521。与WT相比，XS521中TAG-EPA含量增加了154.8%。最后，为了抑制TAG-EPA的降解，在XS521中敲除了一个编码TAG脂肪酶的基因[具体基因9]，导致TAG-EPA含量增加了49.2%-65.3%。我们的工作扩展了通过合成生物学提高微藻以及潜在作物中EPA含量的方法。
