P0011
Cellular and Molecular Characterization of a Putative Glycerol-3-Phosphate Acyltransferase Gene Reveals Key Features Essential for Triacylglycerol Production in Phaeodactylum tricornutum
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou 510632, China;
*Corresponding author. E-mail address: mailto:mailto:thyli@jnu.edu.cn(H.L.).
Abstract
Microalgae have been considered to be the promising source of renewable biodiesel. The marine microalga Phaeodactylum tricornutum has become a model microalga for studying lipid metabolism, and its triacylglycerol (TAG) synthetic pathway provides putative targets for genetic engineering to consummate microalgal lipid productivity. However it is not fully understood about genetic background and metabolic networks of fatty acid biosynthesis in diatom. Glycerol-3-phosphate acyltransferase (GPAT) is a pivotal enzyme that catalyzes the first step of TAG biosynthesis. So far, characterization of GPAT in marine microalgae has been lacking, especially a comprehensive sequence-structure and functional analysis of GPAT. In this study, a putative GPAT was cloned from P. tricornutum. In the GPAT-overexpressing transgenic P. tricornutum, volumes of oil bodies were stimulated and the neutral lipid content was increased by 1.04-fold determined by Nile red fluorescent dye staining. GPAT enzyme activity showed an increase of 2.71-fold. Fatty acid composition was analyzed and appeared a significant difference with higher proportion of unsaturated fatty acids compared with wild type. The results suggested that the identified GPAT could upregulate TAG biosynthesis in P. tricornutum. The results also gained insight into the lipid metabolism in diatom, and represent a valuable target in the improvement of microalgal strains for biofuels.