Genetic Manipulation of the Fatty Acid Composition of Plant Lipids

Somerville, Chris; Browse, John

doi:10.1007/978-1-4757-0274-3_2

Cited by 5 publications

(3 citation statements)

References 61 publications

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“…However, these segregation patterns for Populations III and IV should overlap if the putative B 2 and B 3 alleles contributed by the G. soja lines were identical to the putative B 1 allele in N87-2122-4. Contingency table analyses established that these data sets were distinct or independent from each other (calculated χ 2 = 143.9; tabular value, χ 2 0.05 (16) = 26.3). A t-test indicated that Population IV had significantly greater (P < 0.01) mean ω-3 desaturase activity than Population III.…”

Section: Resultsmentioning

confidence: 97%

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Genetic regulation of linolenic acid concentration in wild soybean Glycine soja accessions

Pantalone

Rebetzke²,

Burton

et al. 1997

J Americ Oil Chem Soc

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Soybean [Glycine max (L.) Merr.] oil from current commercial cultivars typically contains ca. 8% linolenic acid. Inheritance studies have shown that linolenic acid concentration in soybean seed is determined by at least two genes which govern activity of the predominant ω‐6 and ω‐3 desaturases. Selection of germplasm exhibiting homozygous recessive alleles that encode these desaturases has enabled development of soybeans having less than 3.0% linolenic acid. However, accessions of the wild ancestor of modern soybean cultivars, Glycine soja (Sieb. and Zucc.), have oils containing twice the highest linolenic acid concentration found in normal G. max cultivars. Although little is known about inheritance of linolenic acid in wild soybean, it would appear that additional or alternative forms of genes may govern its synthesis. To test this hypothesis, cultivated soybean germplasm was hybridized with wild soybean genotypes having significant differences in linolenic acid concentration. Seed of F3 progeny from these G. max x G. soja populations exhibited distinct segregation patterns for relative estimates of ω‐6 and ω‐3 desaturase activity. Frequency class distribution analyses of the segregation patterns, and linear relations between median ω‐6 or ω‐3 desaturation estimates and corresponding linolenic acid concentration among allelic classes from these populations suggested the high‐linolenic acid trait in wild soybean genotypes was determined by a set of desaturase alleles that were different from corresponding alleles in G. max. Introgression of these alternative alleles in G. max germplasm opens a new avenue of research on the genitic regulation of linolenic acid, and may lead to the production of highly polyunsaturated soybean oils for various industrial applications.

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Section: Resultsmentioning

confidence: 97%

“…When expressed in the antisense orientation in transgenic soybean embryos, the resultant anti-Fad2-1 phenotype exhibited nearly 80% 18:1 (15). The third gene, Fad3, encodes an ω-3 desaturase (16). When this gene is expressed in antisense orientation in transgenic soybean embryos, the anti-Fad3 phenotype exhibited high-18:2 and very low-18:1 (15).…”

mentioning

confidence: 99%

Genetic regulation of linolenic acid concentration in wild soybean Glycine soja accessions

Pantalone

Rebetzke²,

Burton

et al. 1997

J Americ Oil Chem Soc

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“…To examine the role of polyunsaturated fatty acids in chloroplast membranes we have isolated a number of mutants of Arabidopsis thaliana that have leaf lipids with altered acyl composition (28). Physiological analysis of a mutant deficient in synthesis of trienoic fatty acids did not reveal significant changes in photosynthetic properties but did demonstrate that trienoic acid levels influence chloroplast size and number (1 7).…”

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confidence: 99%

Enhanced Thermal Tolerance of Photosynthesis and Altered Chloroplast Ultrastructure in a Mutant of Arabidopsis Deficient in Lipid Desaturation

Hugly

Kunst²,

Browse³

et al. 1989

Plant Physiol.

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149

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A mutant of Arabidopsis thaliana, deficient in activity of the chloroplast n-6 desaturase, accumulated high levels of C16:1 and C18:1 lipids and had correspondingly reduced levels of polyunsaturated lipids. The altered lipid composition of the mutant had pronounced effects on chloroplast ultrastructure, thylakoid membrane protein and chlorophyll content, electron transport rates, and the thermal stability of the photosynthetic membranes. The change in chloroplast ultrastructure was due to a 48% decrease in the amount of appressed membranes that was not compensated for by an increased amount of nonappressed membrane. This resulted in a net loss of 36% of the thylakoid membrane per chloroplast and a corresponding reduction in chlorophyll and protein content. Electrophoretic analysis of the chlorophyll-protein complexes further revealed a small decrease in the amount of light-harvesting complex. Relative levels of whole chain and protosystem 11 electron transport rates were also reduced in the mutant. In addition, the mutation resulted in enhanced thermal stability of photosynthetic electron transport. These observations suggest a central role of polyunsaturated lipids in determining chloroplast structure and maintaining normal photosynthetic function and demonstrate that lipid unsaturation directly affects the thermal stability of photosynthetic membranes.The photosynthetic membranes of higher plants contain an unusually high proportion of polyunsaturated fatty acids.Depending on the plant species, trienoic acids (C16:3 and C18:3) and dienoic acids (C162 and C182) may account for 85% of the total fatty acids found within the chloroplast (1 1

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Mutants of Arabidopsis with alterations in seed lipid fatty acid composition

Lemieux

Miquel

Somerville

et al. 1990

Theoret. Appl. Genetics

262

207

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A diverse collection of mutants of Arabidopsis with altered seed lipid compositions was isolated by determining the fatty acid composition of samples of seed from 3,000 mutagenized lines. A series of mutations was identified that caused deficiencies in the elongation of 18∶1 to 20∶1, desaturation of 18∶1 to 18∶2, and desaturation of 18∶2 to 18∶3. In each of these cases the wild type exhibited incomplete dominance over the mutant allele. These results, along with results from earlier studies, point to a major influence of gene dosage in determining the fatty acid composition of seed lipids. A mutation was also isolated that resulted in increased accumulation of 18∶3. On the basis of the effects on fatty acid composition, the nature of the biochemical lesion in three of the mutants could be tentatively attributed to deficiencies in activities of specific enzymes. The other mutant classes had relatively less pronounced changes in fatty acid composition. These mutants may represent alterations in genes that regulate lipid metabolism or seed development. The availability of the mutants should provide new opportunities to investigate the mechanisms that control seed lipid fatty acid composition.

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Genetic Manipulation of the Fatty Acid Composition of Plant Lipids

Cited by 5 publications

References 61 publications

Genetic regulation of linolenic acid concentration in wild soybean Glycine soja accessions

Genetic regulation of linolenic acid concentration in wild soybean Glycine soja accessions

Enhanced Thermal Tolerance of Photosynthesis and Altered Chloroplast Ultrastructure in a Mutant of Arabidopsis Deficient in Lipid Desaturation

Mutants of Arabidopsis with alterations in seed lipid fatty acid composition

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