Carbon Redistribution from Surface Lipids into Triacylglycerols in Leaves of Arabidopsis by Introducing a Chlamydomonas Diacylglycerol Acyltransferase 2

ABSTRACT: Plants and microalgae have the ability to harness sunlight into energy dense molecules such as triacylglycerols (TAGs). TAGs hold great importance for human and animal nutrition, and are also a source for renewable energy. Acyl-CoA-dependent TAG synthesis by diacylglycerol acyltransferases (DGATs) in oilseeds has been well characterized, but how the ectopic introduction of TAG synthesis in vegetative tissues of plants affects metabolism is largely unknown. Here we report the identification and characterization of several Chlamydomonas reinhardtii Diacylglycerol Acyltransferase Type Two (DGTT) enzymes and their use in engineering TAG biosynthesis in plant vegetative tissues. Focusing on DGTT2 we demonstrate that it can accept a broad range of substrates. Production of DGTT2 in Arabidopsis results in distinct seedling phenotypes and accumulation of TAG with very long chain fatty acids (VLCFA), in both seedlings (23.4-fold increase) and in the leaves of soil-grown plants (13.3-fold increase). Levels of surface lipids, such as waxes and cutins, are decreased in DGTT2-producing lines, consistent with a decreased carbon/acyl flux to the surface lipid pathway. Global transcript analysis showed that very few genes had altered expression. Little to no change in the transcripts of wax/cutin pathway genes was observed in response to altered carbon partitioning into TAGs in the leaves suggesting that the supply of acyl groups for surface lipid biosynthesis is not transcriptionally adjusted in the transgenic lines. As an indication that the DGTT2-producing plants are richer in feed value, the generalist herbivore Spodoptera exigua reared on the transgenic plants gained more weight. Apparently, the substrate specificity of DGTT2 from Chlamydomonas when produced in the Arabidopsis cells leads to diversion of carbon from surface compounds in TAGs and enhances the nutritional value of leaves. 4 biological replicates DGTT2 transgenic plants are compared to 4 biological replicates of wild type

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Brian Fox 

PROVIDER: E-GEOD-38898 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress