Expression of the <i>Arabidopsis ADS1</i> gene in <i>Brassica juncea</i> results in a decreased level of total saturated fatty acids

Yao, Kening; Bacchetto, Roberto G.; Lockhart, Katherine M.; Friesen, L.; Potts, D.; Covello, Patrick S.; Taylor, David C.

doi:10.1046/j.1467-7652.2003.00021.x

Cited by 26 publications

(13 citation statements)

References 25 publications

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“…The physiological functions of ADS enzymes other than FAD5, including those of ADS1 and ADS2, remain to be determined. ADS1 and ADS2 have been demonstrated to be functional fatty acid desaturases (Yao et al, 2003;Heilmann et al, 2004) that lack transit peptides and likely reside in the endoplasmic reticulum. ADS1 and ADS2 gene expression levels are differentially regulated in response to changes in ambient temperature.…”

Section: Discussionmentioning

confidence: 99%

“…The degree of membrane lipid unsaturation influences the biophysical properties of membranes at high or low temperatures (Nishida and Murata, 1996), suggesting a role for ADS1 and ADS2 in temperature acclimation of Arabidopsis reproductive organs (Nishida and Murata, 1996). Although characterized as D9-desaturases in yeast and in seeds of Arabidopsis (Heilmann et al, 2004) and B. juncea (ADS1 only; Yao et al, 2003), the data presented here show that, when retargeted to the plastid, ADS1 and ADS2 can act as palmitoyl-MGDG D7-desaturases and functionally complement the fad5 mutation. The molecular mechanism underlying this apparent switch in regiospecificity has recently been shown to involve interactions between desaturases and different head groups of the lipid substrates found in different subcellular compartments (Heilmann et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…A white spruce (Picea glauca) homolog of At3g15850 has previously been characterized as encoding an 18:0 D9-desaturase by heterologous expression in yeast (Saccharomyces cerevisiae; Marillia et al, 2002). Similarly, two cytoplasmic ADS enzymes from Arabidopsis, ADS1 and ADS2, formed exclusively D9-desaturated fatty acids when expressed in yeast (Heilmann et al, 2004), or predominantly D9 when overexpressed using a seedspecific promoter in Arabidopsis (Heilmann et al, 2004) or in Brassica juncea (ADS1 only; Yao et al, 2003). To date, no formal study of the function of ADS enzymes in the Arabidopsis fad5 mutant has been reported, nor has the restoration of physiological phenotypes associated with this lesion been investigated.…”

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Identification of the Arabidopsis Palmitoyl-Monogalactosyldiacylglycerol Δ7-Desaturase Gene FAD5, and Effects of Plastidial Retargeting of Arabidopsis Desaturases on the fad5 Mutant Phenotype

et al. 2004

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Hexadeca 7,10,10,13 ) is one of the most abundant fatty acids in Arabidopsis (Arabidopsis thaliana) and a functional component of thylakoid membranes, where it is found as an sn-2 ester of monogalactosyldiacylglycerol. The Arabidopsis fad5 mutant lacks activity of the plastidial palmitoyl-monogalactosyldiacylglycerol D7-desaturase FAD5, and is characterized biochemically by the absence of 16:3D 7,10,13 and physiologically by reduced chlorophyll content and a reduced recovery rate after photoinhibition. While the fad5 mutation has been mapped, the FAD5 gene was not unambiguously identified, and a formal functional characterization by complementation of fad5 mutant phenotypes has not been reported. Two candidate genes (At3g15850 and At3g15870) predicted to encode plastid-targeted desaturases at the fad5 chromosomal locus were cloned from fad5 plants and sequenced. A nonsense mutation changing codon TGG (Trp-98) into TGA (stop) was identified in At3g15850 (ADS3), whereas the fad5 At3g15870 allele was identical to wild type (after correction of a sequencing error in the published wild-type genomic At3g15870 sequence). Expression of a genomic clone or cDNA for wild-type At3g15850 conferred on fad5 plants the ability to synthesize 16:3D 7,10,13 and restored leaf chlorophyll content. Arabidopsis carrying a T-DNA insertion in At3g15870 had wild-type levels of both 16:3D 7,10,13 and chlorophyll. Together, these data formally prove that At3g15850 is FAD5. Interestingly, the fad5 phenotype was partially complemented when extraplastidial D9-desaturases of the Arabidopsis desaturase (ADS) family were expressed as fusions with a plastidial transit peptide. Tight correlation between leaf 16:3D 7,10,13 levels and chlorophyll content suggests a role for plastidial fatty acid desaturases in thylakoid formation.Plants that accumulate hexadeca 7,10,13-trienoic acid (16:3D 7,10,13 ) are termed 16:3 plants and include rape (Brassica napus), spinach (Spinacia oleracea), and Arabidopsis (Arabidopsis thaliana). In these plants, 16:3D 7,10,13 can comprise up to 30% of the total fatty acid (Browse et al., 1986), making 16:3D 7,10,13 the second-most-abundant fatty acid after a-linolenic acid (18:3D 9,12,15 ). Pioneering work by Siebertz and Heinz established that 16:3D 7,10,13 is confined to the sn-2 position of monogalactosyldiacylglycerol (MGDG) and results from a sequence of desaturation steps starting with 16:0 (Siebertz and Heinz, 1977). In Arabidopsis, a three-step desaturation pathway is defined by mutants in FAD5 (Kunst et al., 1989), FAD6 (Falcone et al., 1994), and FAD7 (Iba et al., 1993) or FAD8 (McConn et al., 1994, genes that encode desaturases that sequentially introduce the D7, D10, and D13 double bonds, respectively. Plants in which the initial FAD5 D7-desaturation step was compromised and that were devoid of unsaturated 16-carbon fatty acids on MGDG were identified in an ethyl methanesulfonate mutant screen (Kunst et al., 1989). Aside from the absence of 16:3D 7,10,13 from their membrane lipids and a moderate...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Identification of the Arabidopsis Palmitoyl-Monogalactosyldiacylglycerol Δ7-Desaturase Gene FAD5, and Effects of Plastidial Retargeting of Arabidopsis Desaturases on the fad5 Mutant Phenotype

et al. 2004

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“…Seeds from transformed plants contained decreased levels of saturated fatty acids and a slight increase in oleic acid content (Yao et al, 2003). Although the evidence was indirect, the results suggested that AtADS1 may encode a D9 desaturase.…”

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confidence: 94%

Involvement of Arabidopsis ACYL-COENZYME A DESATURASE-LIKE2 (At2g31360) in the Biosynthesis of the Very-Long-Chain Monounsaturated Fatty Acid Components of Membrane Lipids

et al. 2012

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The Arabidopsis (Arabidopsis thaliana) acyl-coenzyme A (CoA) desaturase-like (ADS) gene family contains nine genes encoding fatty acid desaturase-like proteins. The biological function of only one member of the family, fatty acid desaturase5 (AtADS3/ FAD5, At3g15850), is known, and this gene encodes the plastidic palmitoyl-monogalactosyldiacylglycerol D7 desaturase. We cloned seven members of the gene family that are predicted not to have a chloroplast transit peptide and expressed them in the yeast Saccharomyces cerevisiae. All seven have previously undescribed desaturase activity on very-long-chain fatty acid (VLCFA) substrates and exhibit diverse regiospecificity, catalyzing introduction of double bonds relative to the methyl end of the molecule (n-x) at n-6 (AtADS4, At1g06350), n-7 (AtADS1.3, At1g06100 and AtADS4.2, At1g06360), n-9 (AtADS1, At1g06080 and AtADS2, At2g31360) or D9 (relative to the carboxyl end of the molecule) positions (AtADS1.2, At1g06090 and AtADS1.4, At1g06120). Through forward and reverse genetics it was shown that AtADS2 is involved in the synthesis of the 24:1(n-9) and 26:1(n-9) components (X:Y, where X is chain length and Y is number of double bonds) of seed lipids, sphingolipids, and the membrane phospholipids phosphatidylserine, and phosphatidylethanolamine. Plants deficient in AtADS2 expression showed no obvious phenotype when grown under normal growing conditions, but showed an almost complete loss of phosphatidylethanolamine (42:4), phosphatidylserine(42:4), dihydroxy-monohexosylceramide(42:2)-2, trihydroxy-monohexosylceramide(42:2)-3, and trihydroxy-glycosylinositolphosphoceramide(42:2)-3, lipid species that contain the VLCFA 24:1(n-9), and trihydroxyglycosylinositolphosphoceramide(44:2)-3, a lipid containing 26:1(n-9). Acyl-CoA profiling of these plants revealed a major reduction in 24:1-CoA and a small reduction in 26:1-CoA. Overexpression of AtADS2 resulted in a substantial increase in the percentage of glycerolipid and sphingolipids species containing 24:1 and a dramatic increase in the percentage of very-long-chain monounsaturated fatty acids in the acyl-CoA pool. Plants deficient in AtADS1 expression had reduced levels of 26:1(n-9) in seed lipids, but no significant changes in leaf phospholipids or sphingolipids were observed. These findings indicate that the 24-carbon and 26-carbon monounsaturated VLCFAs of Arabidopsis result primarily from VLCFA desaturation, rather than by elongation of long chain monounsaturated fatty acids.

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“…-desaturated fatty acids when expressed in yeast, Arabidopsis, or Brassica juncea (Yao et al, 2003;Heilmann et al, 2004b). ADS3, another member of the Arabidopsis ADS-like gene family, was identified as encoding the FAD5 palmitoylmonogalactosyldiacylglycerol D…”

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Cloning and Characterization of Unusual Fatty Acid Desaturases from Anemone leveillei: Identification of an Acyl-Coenzyme A C20 Δ5-Desaturase Responsible for the Synthesis of Sciadonic Acid

et al. 2007

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The seed oil of Anemone leveillei contains significant amounts of sciadonic acid (20:3D 5,11,14 ; SA), an unusual non-methyleneinterrupted fatty acid with pharmaceutical potential similar to arachidonic acid. Two candidate cDNAs (AL10 and AL21) for the C 20 D 5cis -desaturase from developing seeds of A. leveillei were functionally characterized in transgenic Arabidopsis (Arabidopsis thaliana) plants. The open reading frames of both D 5-desaturases showed some similarity to presumptive acyl-coenzyme A (CoA) desaturases found in animals and plants. When expressed in transgenic Arabidopsis, AL21 showed a broad range of substrate specificity, utilizing both saturated (16:0 and 18:0) and unsaturated (18:2, n-6 and 18:3, n-3) substrates. In contrast, AL10 did not show any activity in wild-type Arabidopsis. Coexpression of AL10 or AL21 with a C 18 D 9 -elongase in transgenic Arabidopsis plants resulted in the production of SA and juniperonic fatty acid (20:4D 5,11,14,17 ). Thus, AL10 acted only on C 20 polyunsaturated fatty acids in a manner analogous to ''front-end'' desaturases. However, neither AL10 nor AL21 contain the cytochrome b 5 domain normally present in this class of enzymes. Acyl-CoA profiling of transgenic Arabidopsis plants and developing A. leveillei seeds revealed significant accumulation of D 5-unsaturated fatty acids as acyl-CoAs compared to the accumulation of these fatty acids in total lipids. Positional analysis of triacylglycerols of A. leveillei seeds showed that D 5 -desaturated fatty acids were present in both sn-2 and sn-1 1 sn-3 positions, although the majority of 16:1D 5 , 18:1D 5 , and SA was present at the sn-2 position. Our data provide biochemical evidence for the A. leveillei D 5 -desaturases using acyl-CoA substrates.In addition to the more prevalent methyleneinterrupted fatty acids, non-methylene-interrupted polyunsaturated fatty acids (NMI-PUFAs) with a D 5cis -ethylenic bond have a global distribution encompassing plant and animal kingdoms and also primitive lower organisms. For example, unusual ethyleneinterrupted D 5,9

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Expression of the Arabidopsis ADS1 gene in Brassica juncea results in a decreased level of total saturated fatty acids

Cited by 26 publications

References 25 publications

Identification of the Arabidopsis Palmitoyl-Monogalactosyldiacylglycerol Δ7-Desaturase Gene FAD5, and Effects of Plastidial Retargeting of Arabidopsis Desaturases on the fad5 Mutant Phenotype

Identification of the Arabidopsis Palmitoyl-Monogalactosyldiacylglycerol Δ7-Desaturase Gene FAD5, and Effects of Plastidial Retargeting of Arabidopsis Desaturases on the fad5 Mutant Phenotype

Involvement of Arabidopsis ACYL-COENZYME A DESATURASE-LIKE2 (At2g31360) in the Biosynthesis of the Very-Long-Chain Monounsaturated Fatty Acid Components of Membrane Lipids

Cloning and Characterization of Unusual Fatty Acid Desaturases from Anemone leveillei: Identification of an Acyl-Coenzyme A C20 Δ5-Desaturase Responsible for the Synthesis of Sciadonic Acid

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