Wang Xiang, Liu Si-Fen, Li Ruo-Yu, Yang Wei-Dong, Liu Jie-Sheng, Lin Carol Sze Ki, Balamurugan Srinivasan, Li Hong-Ye
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China.
School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Biotechnol Biofuels. 2020 Sep 14;13:160. doi: 10.1186/s13068-020-01799-5. eCollection 2020.
Despite the great potential of marine diatoms in biofuel sector, commercially viable biofuel production from native diatom strain is impractical. Targeted engineering of TAG pathway represents a promising approach; however, recruitment of potential candidate has been regarded as critical. Here, we identified a glycerol-3-phosphate acyltransferase 2 (GPAT2) isoform and overexpressed in .
GPAT2 overexpression did not impair growth and photosynthesis. GPAT2 overexpression reduced carbohydrates and protein content, however, lipid content were significantly increased. Specifically, TAG content was notably increased by 2.9-fold than phospho- and glyco-lipids. GPAT2 overexpression elicited the push-and-pull strategy by increasing the abundance of substrates for the subsequent metabolic enzymes, thereby increased the expression of and . Besides, GPAT2-mediated lipid overproduction coordinated the expression of NADPH biosynthetic genes. GPAT2 altered the fatty acid profile in TAGs with C16:0 as the predominant fatty acid moieties. We further investigated the impact of GPAT2 on conferring abiotic stress, which exhibited enhanced tolerance to hyposaline (70%) and chilling (10 ºC) conditions via altered fatty acid saturation level.
Collectively, our results exemplified the critical role of GPAT2 in hyperaccumulating TAGs with altered fatty acid profile, which in turn uphold resistance to abiotic stress conditions.
尽管海洋硅藻在生物燃料领域具有巨大潜力，但利用天然硅藻菌株进行具有商业可行性的生物燃料生产并不实际。对三酰甘油（TAG）途径进行靶向工程改造是一种有前景的方法；然而，筛选潜在候选基因被认为至关重要。在此，我们鉴定出一种甘油-3-磷酸酰基转移酶2（GPAT2）异构体，并在……中过表达。
GPAT2过表达并未损害生长和光合作用。GPAT2过表达降低了碳水化合物和蛋白质含量，然而，脂质含量显著增加。具体而言，TAG含量比磷酸脂质和糖脂显著增加了2.9倍。GPAT2过表达通过增加后续代谢酶底物的丰度引发了“推-拉”策略，从而增加了……的表达。此外，GPAT2介导的脂质过量生产协调了NADPH生物合成基因的表达。GPAT2改变了TAG中的脂肪酸谱，其中C16:0是主要的脂肪酸部分。我们进一步研究了GPAT2对赋予非生物胁迫的影响，其通过改变脂肪酸饱和度水平对低盐（70%）和低温（10℃）条件表现出增强的耐受性。
总体而言，我们的结果例证了GPAT2在脂肪酸谱改变的TAG超积累中的关键作用，这反过来增强了对非生物胁迫条件的抗性。
