Improvement of neutral lipid and polyunsaturated fatty acid biosynthesis by overexpressing a type 2 diacylglycerol acyltransferase in marine diatom Phaeodactylum tricornutum.
Microalgae have been emerging as an important source for the production of bioactive compounds. Marine diatoms can store high amounts of lipid and grow quite quickly. However, the genetic and biochemical characteristics of fatty acid biosynthesis in diatoms remain unclear. Glycerophospholipids are integral as structural and functional components of cellular membranes, as well as precursors of various lipid mediators. In addition, diacylglycerol acyltransferase (DGAT) is a key enzyme that catalyzes the last step of triacylglyceride (TAG) biosynthesis. However, a comprehensive sequence-structure and functional analysis of DGAT in diatoms is lacking. In this study, an isoform of diacylglycerol acyltransferase type 2 of the marine diatom Phaeodactylum tricornutum was characterized. Surprisingly, DGAT2 overexpression in P. tricornutum stimulated more oil bodies, and the neutral lipid content increased by 35%. The fatty acid composition showed a significant increase in the proportion of polyunsaturated fatty acids; in particular, EPA was increased by 76.2%. Moreover, the growth rate of transgenic microalgae remained similar, thereby maintaining a high biomass. Our results suggest that increased DGAT2 expression could alter fatty acid profile in the diatom, and the results thus represent a valuable strategy for polyunsaturated fatty acid production by genetic manipulation.
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China. thyli@jnu.edu.cn.
Ying-Fang
YF
Niu
Meng-Han
MH
Zhang
Da-Wei
DW
Li
Wei-Dong
WD
Yang
Jie-Sheng
JS
Liu
Wei-Bin
WB
Bai
Hong-Ye
HY
Li
D000595:Amino Acid Sequence; D003001:Cloning, Molecular / Q000379:methods; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics*; D017377:Diatoms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D008055:Lipids / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics
D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D051048:Diacylglycerol O-Acyltransferase