Map-Based Cloning of a Gene Controlling Omega-3 Fatty Acid Desaturation in
            <i>Arabidopsis</i>

Arondel, Vincent; Lemieux, Bertrand; Hwang, Inhwan; Gibson, Susan I.; Goodman, Howard M.; Somerville, Chris

doi:10.1126/science.1455229

Cited by 458 publications

(246 citation statements)

References 21 publications

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“…Leaves of these fad3-2 fad7-1/fad7-2 fadS plants contained only 2% trienoic fatty acids. These supplementary genotypes provide important additional tools in studying the consequences of 18:3 deficiency.The three genetic loci involved in generating the triple mutant are known to be the structural genes encoding three membrane-bound, o>-3 desaturases in Arabidopsis (Arondel et al, 1992;Iba et al, 1993; Yadav et al, 1993;Gibson et al, 1994). Our results indicate that these are the only quantitatively significant desaturases contributing to 16:2 and 18:2 desaturation in leaf tissues.…”

supporting

confidence: 48%

“…Instead, much of our current understanding of desaturatlon in plants has come ftom the characterization of seven Arabidopsis mutants, each one deficient in the activity of a different membrane-bound desaturase (Browse and Somerville, 1991). In the absence of purified proteins, the mutants have also made it possible to clone genes that encode the desaturases, using map-based cloning and gene tagging techniques (Arondel et al, 1992;Okuley et al, 1994). In Arabidopsis, there are at least three desaturase enzymes that mediate the conversion of 182 and 16:2 acyl groups to 183 and 163.…”

Section: Introductionmentioning

confidence: 99%

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The Critical Requirement for Linolenic Acid Is Pollen Development, Not Photosynthesis, in an Arabidopsis Mutant.

1996

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The very high proportlons of trlenolc fatty acids found in chloroplast membranes of all higher plants suggest that these llpld otructurtis mlght be essentlal for photosynthasis. We report here on the productisn of Arabidopsis triple mutants that contaln negllglble levels of trlenolc fatty acids. Photosynthesls at 22OC was barely affected, and vegetative growth of the mutants was ldentlcal wlth that of tha wlld type, dm"StratIng that any requlrement for trienoic acyl groups in membrane structure and functlon 1s relatively subtle. Although vegetative growth and development were unaffected, the triple mutants are male sterlle and produce no seed under normal conditlons. Comparisons of psllen development In wlld-type and triple mutant flowersestablished that pallan gralns in the mutant develeped to the tslcellular stege. Exogenous applicatlens of a-llnolenata or jasmonate restered fertlllty. T a k n tsgether, the results demonstrate that the critical role of trlenolc acids ln tha llfe cycle of plants 1s as the precursor of sxylipln, a signallng compound that regulates final maturatlon processes and the release of pollen. INTRODUCTIONThe biophysical reactions of light harvesting and electron transport during photosynthesis take place in a uniquely constructed bilayer membrane, the thylakoid. In all photosynthetic eukaryotes, the complement of atypical glyceralipid molecules that form the foundation of this membrane are characterized by sugar headgroups and avery high leve1 of unsaturation in the fatty acid chains, which compose the central portion of the thylakoid lamella bilayer. For example, menogalactosyldiacylglycerol, the major thylakoid lipid, typically contains >90% af a-linolenic acid (183) er a combination of 183 and hexadecatrienoic (163) acids, depending on the plant species (Jamieson and Reid, 1971). These very high levels of trienoic fatty asids are noteworthy because free radicals that are byproducts of the photosynthetic llght reactions stimulate oxidation of polyunsaturated fatty acids. Because this oxidation might be expected ta medlate against a high degree of unsaturation, it has been inferred that there is a strong selective advantage to having such high levels of trienoic fatty acids in the thylakoid. Therefore, it could be reasoned that these lipid structures must have some critical role in maintaining photosynthetic functlon.To test this line of reasoning directly, we set out to develop Arabldopsis llnes with reduced levels of 18:3 and 163 fatty acids. There are two dlstinct pathways in plant 6811s for the biosynthesis of glycerolipids Rnd the associated praduction To whom correspondence should be addressed. of polyunsaturated fatty acids (Roughan et al., 1980;Browse and Somerville, 1991). 60th pathways are initiated by the synthesis of 16:O-acyl carrier protein (ACP) and 18:l-ACP by the combined action of a type II fatty acid synthase (Shimakata and Stumpf, 1982) and a soluble stearoyl-ACP desaturase (McKeon and Stumpf, 1982;Shanklin and Somerville, 1991) located in the chloroplasts or other p...

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supporting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

The Critical Requirement for Linolenic Acid Is Pollen Development, Not Photosynthesis, in an Arabidopsis Mutant.

1996

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“…In a high density map, closely linked markers will be more precisely ordered if recombination occurs more frequently. Considering the amount of DNA per cM (13 Mbp!cM in Pinus pinaster) and the high amount of repetitive DNA (Plomion et al, 1995b), positional or map-based cloning (Arondel et a!., 1992;Martin et al, 1993) could be easier by using male meioses. However, in a first stage of genomic analysis, a saturated genomic map could be obtained more easily by using meioses from female gametes, because fewer markers would be required for equivalent coverage of the genome (Lange & Boehnke, 1982).…”

Section: Segregation Of Rapd Markersmentioning

confidence: 99%

Recombination rate differences for pollen parents and seed parents in Pinus pinaster

Plomion

O’Malley

1996

Heredity

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Significantly less recombination was observed for the female gametes than for the male gametes in one individual of maritime pine (Pinus pinaster Ait.). Two segregating mapping samples of the same hybrid tree were used for genomic mapping. One sample consisted of diploid tissues from 192 F2 seedlings. The other sample consisted of megagametophytes (haploid maternally derived nutritive tissue) extracted from 156 germinated F2 seedlings. A total of 94 RAPD markers covering 65 per cent of the genome was used for constructing the maps with both samples. Comparison for the total length of the two maps shows that meiotic recombination differs between the haploid and the diploid mapping samples. Map distances in the diploid mapping sample were on average 14 per cent larger than in the megagametophyte sample, corresponding to a 28 per cent greater rate of recombination in the pollen parent.Departure from homogeneity of recombination rate was also tested by marker interval using a likelihood-based method. Inference for greater meiotic recombination during male gametogenesis was verified analytically. A genome-wide reduction in the female gamete's recombination rate in gymnosperms presents interesting evolutionary implications, as this is exactly the opposite trend to that in the angiosperms studied so far. Direct consequences for pine tree breeding are also discussed.

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“…PCC7002 and Anabaena variabilis [15], and also in those of higher plants such as Arabidopsis thaliana [28], rapeseed [29], soybean [29] and spinach [30], as well as in the o93 acyl-lipid desaturases of Synechocystis sp. PCC6803 [9], A. thaliana [31][32][33], rapeseed [33], soybean [33] and mung bean [34]. However, this histidine residue is not conserved in the/19 and/16 desaturases of Synechocystis sp.…”

Section: Site-directed Mutagenesand Of A12 Desaturasementioning

confidence: 99%

Site‐directed mutagenesis of histidine residues in the Δ12 acyl‐lipid desaturase of Synechocystis

et al. 1995

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In the cyanobacterium Synechocystis sp. PCC 6803, there are four acyl-lipid desaturases that are, respectively, specific to the A6, A9, A12 and to3 positions of fatty acids. The desA gene for the A12 acyl-lipid desaturase was modified by sitedirected mutagenesis, such that four of the histidine residues that are conserved in the four desaturases and one histidine residue that is not conserved were replaced by arginine, and the mutated desA genes were overexpressed in Escherichia coil All of these mutations eliminated the A12 desaturase activity. These results demonstrate that the five histidine residues are essential for the activity of the A12 desaturase, perhaps by providing the ligands for the catalytic Fe center.

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Map-Based Cloning of a Gene Controlling Omega-3 Fatty Acid Desaturation in Arabidopsis

Cited by 458 publications

References 21 publications

The Critical Requirement for Linolenic Acid Is Pollen Development, Not Photosynthesis, in an Arabidopsis Mutant.

The Critical Requirement for Linolenic Acid Is Pollen Development, Not Photosynthesis, in an Arabidopsis Mutant.

Recombination rate differences for pollen parents and seed parents in Pinus pinaster

Site‐directed mutagenesis of histidine residues in the Δ12 acyl‐lipid desaturase of Synechocystis

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