DGAT1andPDAT1Acyltransferases Have Overlapping Functions inArabidopsisTriacylglycerol Biosynthesis and Are Essential for Normal Pollen and Seed Development

Zhang, Meng; Fan, Jilian; Taylor, David C.; Ohlrogge, John B.

doi:10.1105/tpc.109.071795

Cited by 431 publications

(456 citation statements)

References 79 publications

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“…However, there was no significant impact on TAG accumulation in pdat1 loss-of-function mutants or in plants overexpressing A. thaliana PDAT, so the role in overall TAG accumulation in Arabidopsis was uncertain (61,62). A clear demonstration of a role for PDAT1 in TAG biosynthesis was provided more recently when its expression was silenced by RNA interference in a dgat1-1 mutant background (63). Seed TAG content was reduced by 70 -80%, and normal seed (and pollen) development was disrupted.…”

Section: Acyl-coa-independent Mechanisms Involved In Tag Synthesismentioning

confidence: 96%

Compartmentation of Triacylglycerol Accumulation in Plants

Chapman

Ohlrogge

2012

Journal of Biological Chemistry

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393

352

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Triacylglycerols from plants, familiar to most people as vegetable oils, supply 25% of dietary calories to the developed world and are increasingly a source for renewable biomaterials and fuels. Demand for vegetable oils will double by 2030, which can be met only by increased oil production. Triacylglycerol synthesis is accomplished through the coordinate action of multiple pathways in multiple subcellular compartments. Recent information has revealed an underappreciated complexity in pathways for synthesis and accumulation of this important energyrich class of molecules. Regulation of Fatty Acid Supply by PlastidsPlant fatty acid (FA) 2 synthesis differs from almost all other eukaryotes in two fundamental features. First, unlike the cytosolic location in other kingdoms, FAs for triacylglycerol (TAG) and membrane synthesis are produced in the plastid compartment of plant cells: chloroplasts in green tissues and proplastids (or leucoplasts) in non-green tissues. Second, the plant FA synthase (FAS) is a dissociable complex with separate proteins for the acyl carrier protein (ACP) and each enzyme (1). After assembly of C 16 and C 18 acyl chains by FAS and desaturation of C 18:0 to C 18:1 , FAs destined for TAG assembly are released from ACP in the plastid stroma by chain-terminating acyl-ACP thioesterases. Two classes of thioesterases designated FATA and FATB are responsible for hydrolysis of unsaturated and saturated acyl-ACPs, respectively, and thus determine in large part the chain length and saturated FA content of plant oils (2). The FA products of FATA and FATB are activated to CoA before export to the endoplasmic reticulum (ER). The subsequent reactions of TAG synthesis belong to the so-called "eukaryotic" pathway of glycerolipid synthesis, which occurs outside the plastid (3, 4). An overview of the compartmentalization of FA supply for TAG is shown in Fig. 1. FA production by plastids can limit TAG accumulation in seeds (5, 6), so increasing flux through FA biosynthesis may perhaps have the single greatest influence on the amount of TAG produced in plant tissues. As in bacteria, fungi, and animals, both in vitro and in vivo evidence indicates that acetylCoA carboxylase (ACCase) is a key rate-determining step that controls FA biosynthesis. ACCase activity is under complex regulation by light, phosphorylation, thioredoxin, PII protein, and product feedback control (7,8). Of course, the flux of carbon to FA synthesis can have multiple regulatory steps, which may explain why efforts to increase seed oil by up-regulating ACCase were only modestly successful (9).Transcriptional regulation of the production of FA for TAG biosynthesis is most directly controlled by the WRINKLED1 transcription factor (7, 10, 11). Arabidopsis wri1 mutants are reduced by 80% in seed oil, and overexpression of WRI1 can increase oil content in seeds of several plants. Targets of WRI1 include ACCase, many enzymes of FAS, and key enzymes and transporters that provide pyruvate and acetyl-CoA in the plastid. Thus, WRI1 can be considered as ...

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Section: Acyl-coa-independent Mechanisms Involved In Tag Synthesismentioning

confidence: 96%

Compartmentation of Triacylglycerol Accumulation in Plants

Chapman

Ohlrogge

2012

Journal of Biological Chemistry

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393

352

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“…Previous studies have shown that overexpression of DGAT1 and WRI1 individually leads to enhanced oil accumulation in vegetative tissues (BouvierNavé et al, 2000;Cernac and Benning, 2004) and also that a synergistic effect is achievable when they are expressed in combination (Vanhercke et al, 2013). WRI1 is a transcription factor that activates the expression of genes encoding multiple enzymes primarily of lower glycolysis and fatty acid synthesis (Cernac and Benning, 2004;Baud et al, 2007), and DGAT1 is the major enzyme that catalyzes the final committed step in TAG synthesis (Katavic et al, 1995;Zhang et al, 2009).…”

Section: Disruption Of Sdp1 In Lines Expressing Wri1 and Dgat1 Leads mentioning

confidence: 99%

“…The dgat1-1 and pdat1-1 mutants are described by Katavic et al (1995) and Zhang et al (2009), respectively. For experiments performed on medium, seeds were surface sterilized, plated on agar plates containing one-half-strength Murashige and Skoog salts (Sigma-Aldrich) with or without the addition of Suc, and imbibed in the dark for 4 d at 4°C.…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

The SUGAR-DEPENDENT1 Lipase Limits Triacylglycerol Accumulation in Vegetative Tissues of Arabidopsis

et al. 2013

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There has been considerable interest recently in the prospect of engineering crops to produce triacylglycerol (TAG) in their vegetative tissues as a means to achieve a step change in oil yield. Here, we show that disruption of TAG hydrolysis in the Arabidopsis (Arabidopsis thaliana) lipase mutant sugar-dependent1 (sdp1) leads to a substantial accumulation of TAG in roots and stems but comparatively much lower TAG accumulation in leaves. TAG content in sdp1 roots increases with the age of the plant and can reach more than 1% of dry weight at maturity, a 50-fold increase over the wild type. TAG accumulation in sdp1 roots requires both ACYL-COENZYME A:DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1) and PHOSPHATIDYLCHOLINE: DIACYLGLYCEROL ACYLTRANSFERASE1 and can also be strongly stimulated by the provision of exogenous sugar. In transgenic plants constitutively coexpressing WRINKLED1 and DGAT1, sdp1 also doubles the accumulation of TAG in roots, stems, and leaves, with levels ranging from 5% to 8% of dry weight. Finally, provision of 3% (w/v) exogenous Suc can further boost root TAG content in these transgenic plants to 17% of dry weight. This level of TAG is similar to seed tissues in many plant species and establishes the efficacy of an engineering strategy to produce oil in vegetative tissues that involves simultaneous manipulation of carbohydrate supply, fatty acid synthesis, TAG synthesis, and also TAG breakdown.

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“…In most seeds, the major lipid storage form is triacylglycerol (TAG), known to be produced by acyl-CoA: diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase (PDAT; Zhang et al, 2009). DGAT1 has been shown in Arabidopsis to be the major, but not the sole, enzyme to contribute to the accumulation of seed TAGs, working together mainly with PDAT (Zhang et al, 2009).…”

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confidence: 99%

Two Acyltransferases Contribute Differently to Linolenic Acid Levels in Seed Oil

et al. 2017

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ORCID IDs: 0000-0001-6929-7859 (S.M.); 0000-0003-3152-0394 (D.S.); 0000-0001-8255-3255 (C.H.); 0000-0003-0489-3072 (K.C.); 0000-0002-9888-7003 (I.F.).Acyltransferases are key contributors to triacylglycerol (TAG) synthesis and, thus, are of great importance for seed oil quality. The effects of increased or decreased expression of ACYL-COENZYME A:DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1) or PHOSPHOLIPID:DIACYLGLYCEROL ACYLTRANSFERASE (PDAT) on seed lipid composition were assessed in several Camelina sativa lines. Furthermore, in vitro assays of acyltransferases in microsomal fractions prepared from developing seeds of some of these lines were performed. Decreased expression of DGAT1 led to an increased percentage of 18:3n-3 without any change in total lipid content of the seed. The tri-18:3 TAG increase occurred predominantly in the cotyledon, as determined with matrix-assisted laser desorption/ionization-mass spectrometry, whereas species with two 18:3n-3 acyl groups were elevated in both cotyledon and embryonal axis. PDAT overexpression led to a relative increase of 18:2n-6 at the expense of 18:3n-3, also without affecting the total lipid content. Differential distributions of TAG species also were observed in different parts of the seed. The microsomal assays revealed that C. sativa seeds have very high activity of diacylglycerol-phosphatidylcholine interconversion. The combination of analytical and biochemical data suggests that the higher 18:2n-6 content in the seed oil of the PDAT overexpressors is due to the channeling of fatty acids from phosphatidylcholine into TAG before being desaturated to 18:3n-3, caused by the high activity of PDAT in general and by PDAT specificity for 18:2n-6. The higher levels of 18:3n-3 in DGAT1-silencing lines are likely due to the compensatory activity of a TAG-synthesizing enzyme with specificity for this acyl group and more desaturation of acyl groups occurring on phosphatidylcholine.

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DGAT1andPDAT1Acyltransferases Have Overlapping Functions inArabidopsisTriacylglycerol Biosynthesis and Are Essential for Normal Pollen and Seed Development

Cited by 431 publications

References 79 publications

Compartmentation of Triacylglycerol Accumulation in Plants

Compartmentation of Triacylglycerol Accumulation in Plants

The SUGAR-DEPENDENT1 Lipase Limits Triacylglycerol Accumulation in Vegetative Tissues of Arabidopsis

Two Acyltransferases Contribute Differently to Linolenic Acid Levels in Seed Oil

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