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Genes, Elongases and Associated Enzyme Systems in Epicuticular Wax Synthesis

  • Penny von Wettstein-Knowles

Abstract

Elongases are enzyme complexes which condense short carbon chains to a primer and prepare the growing chain for the next addition. Soluble plastid fatty acid synthetase (FAS) in higher plants is a special example in which the initial primer is acetyl-acyl carrier protein (ACP), the donor of C2-units is malonyl-ACP and the product palmityl-ACP. Addition of another C2-unit to give stearoyl-ACP is not accomplished by FAS but by the soluble plastid palmityl elongase1,2. Epidermal cells of leek appear to lack the latter complex3. Other elongases are generally believed to be located within the epidermal cells wherein they are affiliated with or are part of the microsomal membranes4,5,6,7. Such complexes carry out the elongation steps required to synthesize the very long chains characteristic of the epidermal waxes. Coenzyme A (CoA) rather than ACP derivatives are thought to serve as substrates for the elongases4,5,6,7,8. The latter fall into two groups depending on whether they use acyl-CoA or β-ketoacyl-CoA chains as primers9,10,11. Before arriving on the outermost surface of the cuticle wall, the long acylCoA chains normally enter an associated enzyme system. Attention has been focused on two such complexes using acyl elongase products4. The reductive system yields aldehydes plus free and esterified primary alcohols. The decarboxylative system, named for the apparent decarboxylation that occurs, gives rise to the hydrocarbons, secondary alcohols and ketones. Elongated acyl-CoA compounds not entering one of the associated pathways may appear in the epicuticular wax as free acids. While these are interpreted as leftovers4, they are occassionally the major lipid class in a wax as, for example, on leaf sheaths of sorghum12. By contrast, such left-overs have not been detected coming from ²-ketoacyl elongase products13. All the latter enter one of two associated enzyme systems which will be detailed below.

Keywords

Primary Alcohol Fatty Acid Synthetase Reductive Pathway Ester Alcohol Major Lipid Class 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    T. Shimakata and P.K. Stumpf, Fatty acid synthetase of Spinacia oleracea leaves, Plant Physiol. 69: 1257 (1982).PubMedCrossRefGoogle Scholar
  2. 2.
    T. Shimakata and P.K. Stumpf, Purification and characterization of β-ketoacyl-ACP synthetase 1 from Spinacia oleracea leaves, Arch. Biochem. Biophys. 220: 39 (1983).CrossRefGoogle Scholar
  3. 3.
    R. Lessire and P.K. Stumpf, Nature of the fatty acid synthetase systems in parenchymal and epidermal cells of Allium porrum L. leaves, Plant Physiol. 73: 614 (1983).PubMedCrossRefGoogle Scholar
  4. 4.
    P. von Wettstein-knowles, Genetics and biosynthesis of plant epicuticular waxes, in: “Advances in the Biochemistry and Physiology of Plant Lipid,” L.-Å. Appelquist and C. Liljenberg, eds., Elsevier/North-Holland Biomédical Press, Amsterdam (1979).Google Scholar
  5. 5.
    C. Cassagne and R. Lessire, Biosynthesis of saturated very long chain fatty acids by purified membrane fractions from leek epidermal cells. Arch. Biochem. Biophys. 191: 146 (1978).PubMedCrossRefGoogle Scholar
  6. 6.
    J.D. Mikkelsen, Synthesis of lipids by epidermal and mesophyll protoplasts isolated from barley leaf sheaths, in: “Biogenesis and Function of Plant Lipids,” P. Mazliak, P. Benveniste, C. Costes, and R. Douce, eds., Elsevier/North-Holland Biomedical Press, Amsterdam (1980).Google Scholar
  7. 7.
    V.P. Agrawal, R. Lessire, and P.K. Stumpf, Biosynthesis of very long chain fatty acids in microsomes from epidermal cells of Allium porrum L., Arch. Biochem. Biophys. 230: 580 (1984).PubMedCrossRefGoogle Scholar
  8. 8.
    J.D. Mikkelsen, Biosynthesis of esterified alkan-2-ols and β-diketones in barley spike epicuticular wax: synthesis of radioactive intermediates, Carlsberg Res. Commun. 49: 391 (1984).CrossRefGoogle Scholar
  9. 9.
    J.D. Mikkelsen and P. von Wettstein-Knowle, Biosynthesis of β-diketones and hydrocarbons in barley spike epicuticular wax, Arch. Biochem. Biophys. 188: 172 (1978).PubMedCrossRefGoogle Scholar
  10. 10.
    P. von Wettstein-Knowles, Biosynthetic relationships between β-dike-tones and esterified alkan-2-ols deduced from epicuticular wax of barley mutants, Molec. gen. Genet. 144: 43 (1976).CrossRefGoogle Scholar
  11. 11.
    P. von Wettstein-Knowles, Role of cer-cqu in epicuticular wax biosynthesis, Biochem. Soc. Tran. (in press) (1986).Google Scholar
  12. 12.
    P. Avato, G. Bianchi, and G. Mariani, Epicuticular waxes of Sorghum and some compositional changes with plant age. Phytochemistry 23: 2843 (1984).CrossRefGoogle Scholar
  13. 13.
    P. von Wettstein-Knowles, unpublished.Google Scholar
  14. 14.
    P. von Wettstein-Knowles and B. Søgaard, Genetic evidence that cer-cqu is a cluster-gene, in: “Barley Genetics IV,” Edinburgh University Press, Edinburgh (1981).Google Scholar
  15. 15.
    B. Søgaard and P. von Wettstein-Knowles, unpublished.Google Scholar
  16. 16.
    P. von Wettstein-Knowles, Genetic control of β-diketone and hydroxy-β-diketone synthesis in epicuticular waxes of barley, Planta 106: 113 (1972).CrossRefGoogle Scholar
  17. 17.
    P. von Wettstein-Knowles, J.D. Mikkelsen, and J.ø. Madsen, Nonan-2-ol esters in sorghum leaf epicuticular wax and their collection by preparative gas chromatography, Carlsberg Res. Commun. 49: 611 (1984).CrossRefGoogle Scholar
  18. 18.
    R. Schüz, W. Heller, and K. Hahlbrock, Substrate specificity of chalcone synthase from Petroselinum hortense, J. Biol. Chem. 258: 6730 (1983).PubMedGoogle Scholar
  19. 19.
    F. Lynen, H. Engeser, J. Friedrich, W. Schindlbeck, R. Seyffert, and F. Wieland, Fatty acid synthetase of yeast and 6-methylsalicylate synthetase of Penicillium patulum — two multienzyme complexes, in: “Microenvironments and Metabolic Compartmentation, “ P.A. Srere and R.W. Estabrook, eds., Academic Press, New York (1978).Google Scholar
  20. 20.
    P. von Wettstein-Knowles, Effects of inhibitors on synthesis of esterified alkan-2-ols in barley spike epicuticular wax, Carlsberg Res. Commun 50: 239 (1985).CrossRefGoogle Scholar
  21. 21.
    T.M. Cheesbrough and P.E. Kolattukudy, Alkane biosynthesis by decarbonylation of aldehydes catalyzed by a particulate preparation from Pisum sativum, Proc. Natl. Acad. Sci. USA 81: 6613 (1984).PubMedCrossRefGoogle Scholar
  22. 22.
    G. Bianchi, Genetic control of composition of epicuticular waxes of maize: a survey, Genet. Agr. 33: 75 (1979).Google Scholar
  23. 23.
    G. Bianchi, P. Avato, and F. Salamini, Surface waxes from grain, leaves, and husks of maize (Zea mays L.), Cereal Chem. 61: 45 (1984).Google Scholar
  24. 24.
    P. Avato, J.D. Mikkelsen, and P. von Wettstein-Knowles, Effect of inhibitors on synthesis of fatty acyl chains present in waxes on developing maize leaves, Carlsberg Res. Commun. 45: 329 (1980).CrossRefGoogle Scholar
  25. 25.
    Maize Genetics Cooperation Newsletter, 60: 150-169 (1986).Google Scholar
  26. 26.
    M.G. Neuffer, L. Jones, and M.S. Zuber, “The Mutants of Maize,” Crop Science Society of America, Madison (1968).Google Scholar
  27. 27.
    G. Bianchi, P. Avato, and F. Salamini, Glossy mutants of maize IX. Chemistry of glossy 4, glossy 8, glossy 15 and glossy 18 surface waxes, Heredity 42: 391 (1979).CrossRefGoogle Scholar
  28. 28.
    P. Avato, G. Bianchi, and F. Salamini, Absence of long chain aldehydes in the wax of the glossy 11 mutant of maize, Phytochemistry 24: 1995 (1985).CrossRefGoogle Scholar
  29. 29.
    U. Lundqvist and P. von Wettstein-Knowles, Dominant mutations at Cer-yy change barley spike wax into leaf blade wax, Carlsberg Res. Commun. 47: 29 (1982).CrossRefGoogle Scholar
  30. 30.
    A. Bianchi, G. Bianchi, P. Avato, and F. Salamini, Biosynthetic pathways of epicuticular wax of maize as assessed by muation, light, plant age and inhibitor studies, Maydica 30: 179 (1985).Google Scholar
  31. 31.
    N.V. Fedoroff, D.B. Furtek, and O.E. Nelson, Cloning of the bronze locus in maize by a simple and generalizable procedure using the transposable controlling element Activator (AC), Proc. Natl. Acad. Sci. USA 81: 3825 (1984).PubMedCrossRefGoogle Scholar
  32. 32.
    J.S. Buckner and P.E. Kolattukudy, Specific inhibition of alkane synthesis with accumulation of very long chain compounds by dithioerythritol, dithiothreitol, and mercaptoethanol in Pisum sativum, Arch. Biochem. Biophys. 156: 34 (1973).PubMedCrossRefGoogle Scholar
  33. 33.
    E.A. Baker, The influence of environment on leaf wax development in Brassica oleracea var. gemmifera, New Phytol. 73: 955 (1974).CrossRefGoogle Scholar
  34. 34.
    P.J. Holloway, G.A. Brown, E.A. Baker, and M.J.K. Macey, Chemical composition and ultrastructure of the epicuticular wax in three lines of Brassica napus (L), Chem. Phys. Lipids 19: 114 (1977).CrossRefGoogle Scholar
  35. 35.
    P.J. Holloway, G.A. Brown, E.A. Baker, and M.J.K. Macey, Chemical composition and ultrastructure of the epicuticular wax in four mutants of Pisum sativum (L), Chem. Phys. Lipids 20: 141 (1977).CrossRefGoogle Scholar
  36. 36.
    H.C. Hoch, C. Pratt, and G.A. Marx, Subepidermal air spaces: basis for the phenotypic expression of the Argentum mutant of Pisum, Amer. J. Bot. 67: 905 (1980).CrossRefGoogle Scholar
  37. 37.
    P.E. Kolattukudy, Enzymatic synthesis of fatty alcohols in Brassica oleracea, Arch. Biochem. Biophys. 142: 701 (1971).PubMedCrossRefGoogle Scholar
  38. 38.
    J.D. Mikkelsen, The effects of inhibitors on the biosynthesis of the long chain lipids with even carbon numbers in barley spike epicuticular wax, Carlsberg Res. Commun. 43: 15 (1978).CrossRefGoogle Scholar
  39. 39.
    A.J. Chu and G.J. Blomquist, Decarboxylation of the tetracosanoic acid to ji-tricosane in the termite Zootermopsis angusticollis, Comp. Biochem. Physiol. 66B: 313 (1980).Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • Penny von Wettstein-Knowles
    • 1
    • 2
  1. 1.Department of PhysiologyCarlsberg LaboratoryCopenhagenDenmark
  2. 2.Institute of GeneticsUniversity of CopenhagenCopenhagenDenmark

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