Abstract
Diacylglycerol acyltransferase (EC 2.3.1.20; DGAT) catalyzes synthesis of triacylglycerol from acyl-CoA and diacylglycerol. Activity of this enzyme and developmental changes in oil accumulation were estimated at various stages of seed growth in soybean germplasm with phenotypic differences in oil content. Oil deposition in seed of these genotypes followed a sigmoid pattern that was modeled to predict incremental rates of oil accumulation during seed development. A strong positive correlation was found between the estimated peak rate of oil deposition (near the mid-term of seed development) and oil concentration in mature seed. At saturating substrate levels, DGAT activity measured near the peak rate of oil deposition also was correlated positively with oil phenotype. In the latter stages of seed development, a positive correlation between estimates of enzyme activity at or below the apparent K m for diolein and comparable oil accumulation rates was attributed to reduced synthesis of substrates and/or potential change in affinity for substrate as suggested by an increase in apparent K m for diolein in older seed. These data indicated that DGAT activity may be a rate-limiting step in triacylglycerol synthesis. However, it is difficult to accept the idea of a single rate-limiting step at the end of a complex metabolic pathway. Because oil is a quantitatively inherited trait, several genes determine genotypic differences in oil content among soybeans. Hence, DGAT activity may be an indicator of coordinated genetic expression of gene-products in the entire glycerolipid synthetic pathway for a given genotype. In any case, results of this investigation demonstrated that genotypic differences in DGAT activity contributed to expression of genetic variation in oil content among soybean gemplasm.
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References
Hartwig, E.E., and T.C. Kilen, Yield and Composition of Soybean Seed from Parents with Different Protein, Similar Yield, Crop Science 31:290–292 (1991).
Palmer, R.G., and T.C. Kilen, Quantitative Genetics and Cytogenetics, in Soybeans: Improvement, Production and Uses, 2nd edn., edited by J.R. Wilcox, American Society of Agronomy, Madison, 1987, pp. 135–197.
Burton, J.W., Quantitative Genetics: Results Relative to Soybean Breeding, Ibid., edited by J.R. Wilcox, American Society of Agronomy, Madison, 1987, pp. 211–242.
Kennedy, E.P., Biosynthesis of Complex Lipids, Fed. Proc. 20:934–940 (1961).
Browse, J., and C. Somerville, Glycerolipid Synthesis: Biochemistry and Regulation, Annu. Rev. Plant Physiol. Plant Mol. Biol. 42:467–506 (1991).
Bhatia, I.S., K. Ahhuja, and P.S. Sukhija, Changes in the Activity of Acetyl-CoA Carboxylase in Germinating and Ripening Sunflower Seeds, Physiol. Plant. 44:141–144 (1978).
Simcox, P.D., W. Garland, V. Deluca, D.T. Canvin, and D.T. Dennis, Respiratory Pathways and Fat Synthesis in Developing Castor Oil Seed, Can. J. Bot. 57:1008–1014 (1979).
Turnham, E., and D.H. Northcote, Changes in Activity of Acetyl-CoA Carboxylase During Rapeseed Formation, Biochem. J. 212:223–229 (1983).
Harwood, J.L., Fatty Acid Metabolism, Annu. Rev. Plant Physiol. Plant Mol. Biol. 39:101–138 (1988).
Roesler, K., D. Shintani, L. Savage, S. Boddupalli, and J. Ohlrogge, Targeting of the Arabidopis Homomeric Acetyl-Coenzyme A Carboxylase to Plastids of Rapeseeds, Plant Physiol. 113:75–81 (1997).
Slack, C.R., P. Roughan, J.A. Browse, and S.E. Gardiner, Some Properties of Cholinephosphotransferase from Developing Safflower Cotyledons, Biochim. Biophys. Acta 833:438–448 (1985).
Hellyer, A., P.F. Leadlay, and A.R. Slabas, Induction, Purification and Characterization of Acyl-ACP Thioesterase from Developing Seeds of Oil Seed Rape (Brassica napus), Plant Mol. Biol. 20:763–780 (1992).
Ichihara, K., S. Noridura, and S. Fujii, Microsomal Phosphatidate Phosphatase in Maturing Safflower Seeds, Plant Physiol. 90:413–419 (1989).
Weslake, R.J., M.K. Pomeroy, T.L. Furukawa, J.L. Golden, D.B. Little, and A. Laroche, Developmental Profile of Diacylglycerol Acyltransferase in Maturing Seeds of Oilseed Rape and Safflower and Microspore-Derived Cultures of Oilseed Rape, Ibid.565–571 (1993).
Ichihara, K., and M. Noda, Fatty Acid Composition and Lipid Synthesis in Developing Safflower Seeds, Phytochemistry 19:49–54 (1980).
Carter, T.E., Jr., J.W. Burton, and C.A. Brim, Registration of NC-101 to NC-112 Soybean Gerimplasm Lines Contrasting in Percent Seed Protein, Crop Sci. 26:841–842 (1986).
Burton, J.W., and R.F. Wilson, Registration of N88-480, a Soybean Germplasm Line with High Concentration of Oil in Seeds, Ibid.313–314 (1994).
Brim, C.A., W.M. Schutz, and F.I. Collins, Nuclear Magnetic Resonance Analysis for Oil in Soybeans [Glycine max (L.) Merr.], Ibid.220–222 (1967).
Salisbury, F.B., and C. Ross, in Plant Physiology, Wadsworth, Belmont, 1969, pp. 410–411.
Gjikpi, P.J., and P.K. Crookston, Effect of Flowering Date on Accumulation of Dry Matter and Protein in Soybean Seeds, Crop Sci. 21:652–655 (1981).
Wilson, R.F. and P. Kwanyuen, Triacylglycerol Synthesis and Metabolism in Germinating Soybean Cotyledons, Biochim. Biophys. Acta 877:231–237 (1986).
Hofstee, B.H.J., Non-Inverted Versus Inverted Plots in Enzyme Kinetics, Nature 184:1296–1298 (1959).
Moorman, D.D., Evaluation of Genotypic Differences in Protein and Oil Metabolism in Developing Soybean Seed, M.Sc. Thesis, North Carolina State University, Raleigh, 1990, pp. 1–96.
Kwanyuen, P., and R.F. Wilson, Isolation and Purification of Diacylglycerol Acyltransferase from Germinating Soybean Cotyledons, Biochim. Biophys. Acta 877:238–245 (1986).
Bradford, M.M., A Rapid and Sensitive Method for the Quantification of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye Binding, Anal. Biochem. 72:248–254 (1976).
Vereshchagin, A.G., Comparative Kinetic Analysis of Oil Accumulation in Maturing Seeds, Plant Physiol. Biochem. 29:385–393 (1991).
Rubel, A., R.W. Rinne, and D.T. Canvin, Protein, Oil and Fatty Acid in Developing Soybean Seeds, Crop Sci. 12:739–742 (1972).
Egli, D.B., J.E. Leggett, and J.M. Wood, Influence of Soybean Seed Size and Position on the Rate and Duration of Filling, Ibid.127–130 (1978).
Swank, J.C., D.B. Egli, and T.W. Pfeiffer, Seed Growth Characteristics of Soybean Genotypes Differing in Duration of Seed Fill, Ibid.85–89 (1987).
Tinius, C.N., J.W. Burton, and T.E. Carter, Jr., Recurrent Selection for Seed Size in Soybean. II. Indirect Effects on Seed Growth Rate, Ibid.1480–1483 (1992).
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Settlage, S.B., Kwanyuen, P. & Wilson, R.F. Relation between diacylglycerol acyltransferase activity and oil concentration in soybean. J Amer Oil Chem Soc 75, 775–781 (1998). https://doi.org/10.1007/s11746-998-0225-2
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DOI: https://doi.org/10.1007/s11746-998-0225-2