Journal article
Oil-Producing Metabolons Containing DGAT1 Use Separate Substrate Pools from those Containing DGAT2 or PDAT
Plant physiology (Bethesda), Vol.184(2), pp.720-737
10/2020
PMID: 32732347
Abstract
Seed triacylglycerol (TAG) biosynthesis involves a metabolic network containing multiple different diacylglycerol (DAG) and acyl donor substrate pools. This network of pathways overlaps with those for essential membrane lipid synthesis and utilizes multiple different classes of TAG biosynthetic enzymes. Acyl flux through this network ultimately dictates the final oil fatty acid composition. Most strategies to alter seed oil composition involve the overexpression of lipid biosynthetic enzymes, but how these enzymes are assembled into metabolons and which substrate pools are used by each is still not well understood. To understand the roles of different classes of TAG biosynthetic acyltransferases in seed oil biosynthesis, we utilized the Arabidopsis (
) diacylglycerol acyltransferase mutant
(in which phosphatidylcholine:diacylglycerol acyltransferase (AtPDAT1) is the major TAG biosynthetic enzyme), and enhanced TAG biosynthesis by expression of Arabidopsis acyltransferases AtDGAT1 and AtDGAT2, as well as the DGAT2 enzymes from soybean (
), and castor (
), followed by isotopic tracing of glycerol flux through the lipid metabolic network in developing seeds. The results indicate each acyltransferase has a unique effect on seed oil composition. AtDGAT1 produces TAG from a rapidly produced phosphatidylcholine-derived DAG pool. However, AtPDAT1 and plant DGAT2 enzymes utilize a different and larger bulk phosphatidylcholine-derived DAG pool that is more slowly turned over for TAG biosynthesis. Based on metabolic fluxes and protein:protein interactions, our model of TAG synthesis suggests that substrate channeling to select enzymes and spatial separation of different acyltransferases into separate metabolons affect efficient TAG production and oil fatty acid composition.
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Details
- Title
- Oil-Producing Metabolons Containing DGAT1 Use Separate Substrate Pools from those Containing DGAT2 or PDAT
- Creators
- Anushobha Regmi - Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406Jay Shockey - United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124Hari Kiran Kotapati - Washington State UniversityPhilip D Bates - Washington State University, Biological Chemistry, Institute of
- Publication Details
- Plant physiology (Bethesda), Vol.184(2), pp.720-737
- Academic Unit
- Biological Chemistry, Institute of
- Grant note
- P20 GM103476 / NIGMS NIH HHS
- Identifiers
- 99900970440601842
- Copyright
- Attribution 4.0 International (CC BY 4.0): https://creativecommons.org/licenses/by/4.0/
- Language
- English
- Resource Type
- Journal article