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Lipidomic analysis of Arabidopsis seed genetically engineered to contain DHA.

Zhou XR, Callahan DL, Shrestha P, Liu Q, Petrie JR, Singh SP - Front Plant Sci (2014)

Bottom Line: Metabolic engineering of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) in oilseeds has been one of the key targets in recent years.Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the triacylglycerol (TAG), diacylglycerol (DAG) and phospholipid (PL) lipid classes in the transgenic and wild type Arabidopsis seeds at both developing and mature stages.Trace amounts of di-DHA PC and tri-DHA TAG were identified and confirmed by high resolution MS/MS.

View Article: PubMed Central - PubMed

Affiliation: Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research Organisation Canberra, ACT, Australia ; Plant Industry, Commonwealth Scientific and Industrial Research Organisation Canberra, ACT, Australia.

ABSTRACT
Metabolic engineering of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) in oilseeds has been one of the key targets in recent years. By expressing a transgenic pathway for enhancing the synthesis of the ω3 LC-PUFA docosahexaenoic acid (DHA) from endogenous α-linolenic acid (ALA), we obtained the production of fish oil-like proportions of DHA in Arabidopsis seed oil. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the triacylglycerol (TAG), diacylglycerol (DAG) and phospholipid (PL) lipid classes in the transgenic and wild type Arabidopsis seeds at both developing and mature stages. The analysis identified the appearance of several abundant DHA-containing phosphatidylcholine (PC), DAG and TAG molecular species in mature seeds. The relative abundances of PL, DAG, and TAG species showed a preferred combination of LC-PUFA with ALA in the transgenic seeds, where LC-PUFA were esterified in positions usually occupied by 20:1ω9. Trace amounts of di-DHA PC and tri-DHA TAG were identified and confirmed by high resolution MS/MS. Studying the lipidome in transgenic seeds provided insights into where DHA accumulated and combined with other fatty acids of neutral and phospholipids from the developing and mature seeds.

No MeSH data available.


Abundance of different diacylglycerol (DAG) species in the WT and the GA7 Arabidopsis seeds. DAG species are labeled in format of DAG target/X:Y, where target will be 20:1 (A), SDA (B), EPA (C) or DHA (D), with another acyl containing X number of carbons and Y number of double bonds. Data are shown as the mean of triplicate analysis with the error bars representing the standard deviations.
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Figure 6: Abundance of different diacylglycerol (DAG) species in the WT and the GA7 Arabidopsis seeds. DAG species are labeled in format of DAG target/X:Y, where target will be 20:1 (A), SDA (B), EPA (C) or DHA (D), with another acyl containing X number of carbons and Y number of double bonds. Data are shown as the mean of triplicate analysis with the error bars representing the standard deviations.

Mentions: Analysis of DAG species containing one of the four targeted fatty acids showed that both the GA7 developing and mature seeds accumulated substantial amounts of DHA-containing DAG, with low amounts of DAG containing the intermediate SDA or EPA (Figure S3). In WT, the most abundant 20:1-containing DAG was DAG 20:1/18:2 (52.2% among all 20:1-containing DAG), followed by DAG 20:1/18:3. In contrast, the GA7 mature seeds showed about five times more DAG 20:1/18:3 than DAG 20:1/18:2 (65.0% vs. 12.2% among all 20:1-containing DAG). The major DAG species among all 4 analyzed DAG groups were the DAG molecules containing C18:3(Figure 6). In GA7 mature seed lipids, a relatively high percentage of DAG SDA/16:0 and DAG EPA/16:0 was also found, making up 16.0% of total SDA-containing DAG and 23.0% of total EPA-containing DAG, although the overall amounts were low (Figures 6B,C). In contrast, DAG DHA/16:0 was found only at 10.7% of the total DHA-containing DAG, while the predominant DAG DHA/18:3 species was 52.0%.


Lipidomic analysis of Arabidopsis seed genetically engineered to contain DHA.

Zhou XR, Callahan DL, Shrestha P, Liu Q, Petrie JR, Singh SP - Front Plant Sci (2014)

Abundance of different diacylglycerol (DAG) species in the WT and the GA7 Arabidopsis seeds. DAG species are labeled in format of DAG target/X:Y, where target will be 20:1 (A), SDA (B), EPA (C) or DHA (D), with another acyl containing X number of carbons and Y number of double bonds. Data are shown as the mean of triplicate analysis with the error bars representing the standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150447&req=5

Figure 6: Abundance of different diacylglycerol (DAG) species in the WT and the GA7 Arabidopsis seeds. DAG species are labeled in format of DAG target/X:Y, where target will be 20:1 (A), SDA (B), EPA (C) or DHA (D), with another acyl containing X number of carbons and Y number of double bonds. Data are shown as the mean of triplicate analysis with the error bars representing the standard deviations.
Mentions: Analysis of DAG species containing one of the four targeted fatty acids showed that both the GA7 developing and mature seeds accumulated substantial amounts of DHA-containing DAG, with low amounts of DAG containing the intermediate SDA or EPA (Figure S3). In WT, the most abundant 20:1-containing DAG was DAG 20:1/18:2 (52.2% among all 20:1-containing DAG), followed by DAG 20:1/18:3. In contrast, the GA7 mature seeds showed about five times more DAG 20:1/18:3 than DAG 20:1/18:2 (65.0% vs. 12.2% among all 20:1-containing DAG). The major DAG species among all 4 analyzed DAG groups were the DAG molecules containing C18:3(Figure 6). In GA7 mature seed lipids, a relatively high percentage of DAG SDA/16:0 and DAG EPA/16:0 was also found, making up 16.0% of total SDA-containing DAG and 23.0% of total EPA-containing DAG, although the overall amounts were low (Figures 6B,C). In contrast, DAG DHA/16:0 was found only at 10.7% of the total DHA-containing DAG, while the predominant DAG DHA/18:3 species was 52.0%.

Bottom Line: Metabolic engineering of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) in oilseeds has been one of the key targets in recent years.Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the triacylglycerol (TAG), diacylglycerol (DAG) and phospholipid (PL) lipid classes in the transgenic and wild type Arabidopsis seeds at both developing and mature stages.Trace amounts of di-DHA PC and tri-DHA TAG were identified and confirmed by high resolution MS/MS.

View Article: PubMed Central - PubMed

Affiliation: Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research Organisation Canberra, ACT, Australia ; Plant Industry, Commonwealth Scientific and Industrial Research Organisation Canberra, ACT, Australia.

ABSTRACT
Metabolic engineering of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) in oilseeds has been one of the key targets in recent years. By expressing a transgenic pathway for enhancing the synthesis of the ω3 LC-PUFA docosahexaenoic acid (DHA) from endogenous α-linolenic acid (ALA), we obtained the production of fish oil-like proportions of DHA in Arabidopsis seed oil. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the triacylglycerol (TAG), diacylglycerol (DAG) and phospholipid (PL) lipid classes in the transgenic and wild type Arabidopsis seeds at both developing and mature stages. The analysis identified the appearance of several abundant DHA-containing phosphatidylcholine (PC), DAG and TAG molecular species in mature seeds. The relative abundances of PL, DAG, and TAG species showed a preferred combination of LC-PUFA with ALA in the transgenic seeds, where LC-PUFA were esterified in positions usually occupied by 20:1ω9. Trace amounts of di-DHA PC and tri-DHA TAG were identified and confirmed by high resolution MS/MS. Studying the lipidome in transgenic seeds provided insights into where DHA accumulated and combined with other fatty acids of neutral and phospholipids from the developing and mature seeds.

No MeSH data available.