Identification and characterization of an efficient acyl-CoA: diacylglycerol acyltransferase 1 (DGAT1) gene from the microalga Chlorella ellipsoidea.
Identification and characterization of an efficient acyl-CoA: diacylglycerol acyltransferase 1 (DGAT1) gene from the microalga Chlorella ellipsoidea.
复制标题
微藻椭球小球藻中有效酰基辅酶 A：二酰基甘油酰基转移酶 1 (DGAT1) 基因的鉴定和表征
DOI：
10.1186/s12870-017-0995-5
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发表时间：
2017-02-21
影响因子：
5.3
通讯作者：
Hu Z
中科院分区：
文献类型：
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作者：
Guo X;Fan C;Chen Y;Wang J;Yin W;Wang RR;Hu Z
背景：三酰甘油（TAG）形式的油是真核细胞最重要的能量储存形式。二酰基甘油酰基转移酶（DGAT）被认为是TAG积累的限速酶。小球藻是一种单细胞真核绿色藻类，作为一种潜在的可再生能源生产原料，引起了人们的广泛关注。结果：从椭圆小球藻（Chlorella ellipsoidea）中获得了一个DGAT 1基因的全长cDNA，该基因编码一个可能的二酰基甘油酰基转移酶1（DGAT 1，EC 2.3.1.20）。该cDNA的开放阅读框为2,142 bp，命名为CeDGAT 1，编码713个氨基酸，与高等植物DGAT 1的同源性不超过40%。转录本分析表明，氮饥饿条件下CeDGAT 1的表达水平显着增加，从而导致三酰甘油（TAG）的显着积累。通过恢复其产生TAG的能力，在酵母四重突变体菌株H1246中证实了CeDGAT 1活性。在表达CeDGAT 1后，野生型酵母（INVSc 1）中的总脂肪酸含量增加了142%，显著高于用来自高等植物（甚至包括油料作物大豆）的DGAT 1 s转化的酵母。在野生型拟南芥和甘蓝型油菜中，一氧化氮合酶启动子下的CeDGAT 1基因过表达。Westar显著地分别增加了8-37%和12-18%的油含量和9-15%和6- 29%的平均1,000粒种子重量，但没有改变种子油的脂肪酸组成。在转基因拟南芥和B中，1，000粒种子总脂质含量的净增加高达25-50%。结论：我们在C. napus中鉴定了DGAT 1基因。并证实了它在TAG积累中起着重要作用。这是DGAT 1在小球藻中的首次功能分析。这些信息对于理解小球藻中的脂质合成和积累以及用于基因工程以提高微藻和油料植物中的油产量是重要的。
Background:Oil in the form of triacylglycerols (TAGs) is quantitatively the most important storage form of energy for eukaryotic cells. Diacylglycerol acyltransferase (DGAT) is considered the rate-limiting enzyme for TAG accumulation. Chlorella, a unicellular eukaryotic green alga, has attracted much attention as a potential feedstock for renewable energy production. However, the function of DGAT1 in Chlorella has not been reported.Results:A full-length cDNA encoding a putative diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) was obtained from Chlorella ellipsoidea. The 2,142 bp open reading frame of this cDNA, designated CeDGAT1, encodes a protein of 713 amino acids showing no more than 40% identity with DGAT1s of higher plants. Transcript analysis showed that the expression level of CeDGAT1 markedly increased under nitrogen starvation, which led to significant triacylglycerol (TAG) accumulation. CeDGAT1 activity was confirmed in the yeast quadruple mutant strain H1246 by restoring its ability to produce TAG. Upon expression of CeDGAT1, the total fatty acid content in wild-type yeast (INVSc1) increased by 142%, significantly higher than that transformed with DGAT1s from higher plants, including even the oil crop soybean. The over-expression of CeDGAT1 under the NOS promoter in wild-type Arabidopsis thaliana and Brassica napus var. Westar significantly increased the oil content by 8-37% and 12-18% and the average 1,000-seed weight by 9-15% and 6-29%, respectively, but did not alter the fatty acid composition of the seed oil. The net increase in the 1,000-seed total lipid content was up to 25-50% in both transgenic Arabidopsis and B. napus.Conclusions:We identified a gene encoding DGAT1 in C. ellipsoidea and confirmed that it plays an important role in TAG accumulation. This is the first functional analysis of DGAT1 in Chlorella. This information is important for understanding lipid synthesis and accumulation in Chlorella and for genetic engineering to enhance oil production in microalgae and oil plants.