Inhibitors of fatty acid biosynthesis in sunflower seeds

Pleite, Rafael; Martı́nez-Force, Enrique; Garcés, Rafael

doi:10.1016/j.jplph.2005.11.017

Cited by 7 publications

(5 citation statements)

References 40 publications

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“…To quantify this capacity, we defined the saturation coefficient as the relationship between the radiolabel in TAGs that contain the products of this blockage, including both the stearic acid and the increment in the VLCFAs synthesized from it, and the radioactivity present in the products of unsaturation (Figure 1). We found that the relative incorporation into TAG was maximal in the presence of 10 mM MV (14). Moreover, in the presence of 10 mM MV, two well-defined and distinct behaviors were observed in the high-oleic lines assayed: one with a coefficient greater than 20 and others with a coefficient of less than 10 (Figure 1).…”

Section: Resultsmentioning

confidence: 86%

“…Selection of the Lines. Our initial aim was to determine whether it is possible to identify lines with alleles whose main acyl-ACP thioesterase acts predominantly on the stearoyl-ACP after incubating developing sunflower seeds with radioactive acetate as the substrate and methyl viologen (MV) to inhibit the SAD (14). A series of high-oleic sunflower lines were analyzed in this way.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, it should be possible to select the best lines to be crossed with mutants in which the main SAD pathway is blocked, such as the CAS-3 high-stearic sunflower mutant line for example. It has been demonstrated that methyl viologen (MV) inhibits the conversion of stearoyl-ACP to oleoyl-ACP (14), which accumulates in the interior of the plastid. Thus, if a sunflower line has good thioesterase activity against stearic, the stearic acid could be exported to the cytoplasm more efficiently, and it would more readily be found in the reserve lipids than in a line with thioesterase that acts weakly on saturated fatty acids.…”

Section: Introductionmentioning

confidence: 99%

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Increase of the Stearic Acid Content in High-Oleic Sunflower (Helianthus annuus) Seeds

Pleite

Martı́nez-Force

Garcés

2006

J. Agric. Food Chem.

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We have performed an "in vivo" study of storage lipid synthesis in developing sunflower seeds, from several high-oleic genetic backgrounds, using radioactive acetate in conjunction with methyl viologen as an inhibitor of the stearoyl-ACP desaturase. As such, some backgrounds showed stronger acyl-ACP thioesterase activity on stearoyl-ACP. We have developed a saturation coefficient that quantifies stearoyl-ACP thioesterase activity among sunflower lines based on their ability to synthesize saturated fatty acids under conditions when the competing stearoyl-ACP desaturase is inhibited by methyl viologen. The saturation coefficient is defined as the ratio of sum of the stearic, araquidic, and behenic saturated fatty acid contents to the unsaturated fatty acid content. On the basis of this coefficient, we were able to select high-oleic lines that, when crossed with the high-stearic CAS-3 line, developed progeny with high-stearic content on a high-oleic background. This approach has enabled us to identify lines with a combination of alleles that synthesized oils with more stearic acid in a high-oleic background, 21% stearic and 62% oleic contents. In contrast, lines with a lower index produced progeny that contained less stearic acid, similar to those obtained previously, that were 13% stearic acid content in high-oleic background. This method could also be used for other metabolic pathways where the blockage of a principal pathway may activate a secondary pathway. However, it should be emphasized that although the stearic acid content could be augmented it was not possible to break the association or the epistatic relationship that exists between the genes that permit a high-stearic phenotype and those that determine a high-oleic background.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increase of the Stearic Acid Content in High-Oleic Sunflower (Helianthus annuus) Seeds

Pleite

Martı́nez-Force

Garcés

2006

J. Agric. Food Chem.

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“…Seed fatty acids are cell synthesized in the plastids, later exported into the cytosol, and finally, oil (triacylglycerol) is synthesized in the endoplasmic reticulum (ER). The multiple enzymatic reactions taking place in the stroma of plastids produce 16‐ and 18‐carbon fatty acids, about of which 75% are unsaturated (Dar et al, 2017; Ohlrogge and Browse, 1995; Pleite et al, 2006; Somerville et al, 2000) (Fig. 1).…”

Section: Replacing Trans Fatty Acids (Tfa) In Food Processingmentioning

confidence: 99%

Current Status of High Oleic Seed Oils in Food Processing

Zambelli

2020

J Americ Oil Chem Soc

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Dietary trans fatty acids (TFA) from industrial partial hydrogenation continue to occupy the attention of health and regulatory authorities, prompting renewed recommendations and regulations around the world. Partial hydrogenation of liquid oils was widely used because it increases the oxidative stability and plasticity of vegetable oils. The development of high oleic (HO) oils appeared as an efficient and healthy strategy to replace partially hydrogenated vegetable oils. At present, the main sources of HO oils are the HO varieties of sunflower, canola, and soybean, covering almost the entire market. Although all these HO crops show oleic acid contents higher than 70%, they can be differentiated by their fatty acid profiles. Recent clinical evidence suggests that polyunsaturated content should also be considered since its intake has been associated with coronary heart disease. Comparison of the fatty acid compositions, places HO sunflower as the best option in terms of oxidative stability and beneficial effects on the health of consumers.

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“…Two types of acyl-ACPs thioesterases have been identified in higher plants such as sunflowers: FatA and FatB. FatA thioesterases preferentially act on long chain fatty acids, and have particularly high specificity for 18:1-ACP and a lower affinity for 16:0-ACP and 18:0-ACP [9]. To address the needs of the confectionery industry for saturated fatty acids, high stearic acid content oils have been developed mainly by genetic modification of the FatA stearoyl-ACP thioesterase and the SAD stearoyl-ACP desaturase [10,11].…”

Section: Introductionmentioning

confidence: 99%

SMART – Sunflower Mutant population And Reverse genetic Tool for crop improvement

Kumar¹,

Boualem

Bhattacharya³

et al. 2013

BMC Plant Biol

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BackgroundSunflower (Helianthus annuus L.) is an important oilseed crop grown widely in various areas of the world. Classical genetic studies have been extensively undertaken for the improvement of this particular oilseed crop. Pertaining to this endeavor, we developed a “chemically induced mutated genetic resource for detecting SNP by TILLING” in sunflower to create new traits.ResultsTo optimize the EMS mutagenesis, we first conducted a “kill curve” analysis with a range of EMS dose from 0.5% to 3%. Based on the observed germination rate, a 50% survival rate i.e. LD50, treatment with 0.6% EMS for 8 hours was chosen to generate 5,000 M2 populations, out of which, 4,763 M3 plants with fertile seed set. Phenotypic characterization of the 5,000 M2 mutagenised lines were undertaken to assess the mutagenesis quality and to identify traits of interest. In the M2 population, about 1.1% of the plants showed phenotypic variations. The sunflower TILLING platform was setup using Endo-1-nuclease as mismatch detection system coupled with an eight fold DNA pooling strategy. As proof-of-concept, we screened the M2 population for induced mutations in two genes related to fatty acid biosynthesis, FatA an acyl-ACP thioesterase and SAD the stearoyl-ACP desaturase and identified a total of 26 mutations.ConclusionBased on the TILLING of FatA and SAD genes, we calculated the overall mutation rate to one mutation every 480 kb, similar to other report for this crop so far. As sunflower is a plant model for seed oil biosynthesis, we anticipate that the developed genetic resource will be a useful tool to identify novel traits for sunflower crop improvement.

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Inhibitors of fatty acid biosynthesis in sunflower seeds

Cited by 7 publications

References 40 publications

Increase of the Stearic Acid Content in High-Oleic Sunflower (Helianthus annuus) Seeds

Increase of the Stearic Acid Content in High-Oleic Sunflower (Helianthus annuus) Seeds

Current Status of High Oleic Seed Oils in Food Processing

SMART – Sunflower Mutant population And Reverse genetic Tool for crop improvement

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