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Bottlenecks in erucic acid accumulation in genetically engineered ultrahigh erucic acid Crambe abyssinica.

Guan R, Lager I, Li X, Stymne S, Zhu LH - Plant Biotechnol. J. (2013)

Bottom Line: Crambe abyssinica is an alternative promising producer of this acid as it has 55%-60% of erucic acid in its oil.In this study, we further investigated different aspects of oil biosynthesis in the developing GM Crambe seeds in comparison with wild-type (Wt) Crambe, rapeseed and safflower (Carthamus tinctorius).Likely bottlenecks in the accumulation of erucic acid during early stages of GM Crambe seed development are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.

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Time course incorporation of radioactivity into various lipids in microsomal preparations from developing seeds of different species, incubated with [14C]glycerol 3-phosphate and nonradioactive 22:1-CoA. Wt, wild type; GM, genetically modified; LPA, lysophosphatidic acid; MAG, monoacylglycerol; PA, phosphatidic acid; DAG, diacylglycerol; PC, phosphatidylcholine; TAG, triacylglycerols. Results are shown from triplicate samples ± SD.
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fig04: Time course incorporation of radioactivity into various lipids in microsomal preparations from developing seeds of different species, incubated with [14C]glycerol 3-phosphate and nonradioactive 22:1-CoA. Wt, wild type; GM, genetically modified; LPA, lysophosphatidic acid; MAG, monoacylglycerol; PA, phosphatidic acid; DAG, diacylglycerol; PC, phosphatidylcholine; TAG, triacylglycerols. Results are shown from triplicate samples ± SD.

Mentions: Incubations of Wt and GM Crambe and safflower microsomes with [14C]G-3-P and 22:1-CoA yielded only 2.5%–3.5% of the radioactivity seen in complex lipids with 18:1-CoA and [14C]G-3-P substrates (compare Figures1 and 4). In Wt Crambe, the LPA substrate remained the most labelled lipid at all incubation times. The next highly labelled lipid was comigrating with monoacylglycerol (MAG) according to the authentic standard. The most likely origin of this compound is dephosphorylation of the formed lyso-PA by a phospholipase of C type. Only a very small amount of PA was produced. In GM Crambe, a substantial amount of the LPA was converted to PA, demonstrating that the introduced Limnanthes LPAAT was able to acylate 22:1-CoA to 22:1-LPA. No labelled MAG could be detected in the assays with the GM Crambe lines, indicating that the Limnanthes LPAAT efficiently outcompeted the enzyme responsible for the formation MAG in Wt membranes. The safflower microsomes could acylate 22:1-CoA to G-3-P to produce 22:1-LPA, of which a substantial part was converted to MAG, but, interestingly, a large proportion was also found in PA and even higher in PC. We could not detect any labelled DAG or TAG in any of these incubations for all the species (Figure4). However, it should be noted that the total amount of 14C incorporation into complex lipids was very low and the label in these lipids might be below the detection limit.


Bottlenecks in erucic acid accumulation in genetically engineered ultrahigh erucic acid Crambe abyssinica.

Guan R, Lager I, Li X, Stymne S, Zhu LH - Plant Biotechnol. J. (2013)

Time course incorporation of radioactivity into various lipids in microsomal preparations from developing seeds of different species, incubated with [14C]glycerol 3-phosphate and nonradioactive 22:1-CoA. Wt, wild type; GM, genetically modified; LPA, lysophosphatidic acid; MAG, monoacylglycerol; PA, phosphatidic acid; DAG, diacylglycerol; PC, phosphatidylcholine; TAG, triacylglycerols. Results are shown from triplicate samples ± SD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4286110&req=5

fig04: Time course incorporation of radioactivity into various lipids in microsomal preparations from developing seeds of different species, incubated with [14C]glycerol 3-phosphate and nonradioactive 22:1-CoA. Wt, wild type; GM, genetically modified; LPA, lysophosphatidic acid; MAG, monoacylglycerol; PA, phosphatidic acid; DAG, diacylglycerol; PC, phosphatidylcholine; TAG, triacylglycerols. Results are shown from triplicate samples ± SD.
Mentions: Incubations of Wt and GM Crambe and safflower microsomes with [14C]G-3-P and 22:1-CoA yielded only 2.5%–3.5% of the radioactivity seen in complex lipids with 18:1-CoA and [14C]G-3-P substrates (compare Figures1 and 4). In Wt Crambe, the LPA substrate remained the most labelled lipid at all incubation times. The next highly labelled lipid was comigrating with monoacylglycerol (MAG) according to the authentic standard. The most likely origin of this compound is dephosphorylation of the formed lyso-PA by a phospholipase of C type. Only a very small amount of PA was produced. In GM Crambe, a substantial amount of the LPA was converted to PA, demonstrating that the introduced Limnanthes LPAAT was able to acylate 22:1-CoA to 22:1-LPA. No labelled MAG could be detected in the assays with the GM Crambe lines, indicating that the Limnanthes LPAAT efficiently outcompeted the enzyme responsible for the formation MAG in Wt membranes. The safflower microsomes could acylate 22:1-CoA to G-3-P to produce 22:1-LPA, of which a substantial part was converted to MAG, but, interestingly, a large proportion was also found in PA and even higher in PC. We could not detect any labelled DAG or TAG in any of these incubations for all the species (Figure4). However, it should be noted that the total amount of 14C incorporation into complex lipids was very low and the label in these lipids might be below the detection limit.

Bottom Line: Crambe abyssinica is an alternative promising producer of this acid as it has 55%-60% of erucic acid in its oil.In this study, we further investigated different aspects of oil biosynthesis in the developing GM Crambe seeds in comparison with wild-type (Wt) Crambe, rapeseed and safflower (Carthamus tinctorius).Likely bottlenecks in the accumulation of erucic acid during early stages of GM Crambe seed development are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.

Show MeSH