Plant Molecular Biology

, Volume 27, Issue 5, pp 875–886

Modification of Brassica napus seed oil by expression of the Escherichia coli fabH gene, encoding 3-ketoacyl-acyl carrier protein synthase III

  • Ira I. G. S. Verwoert
  • Karin H. van der Linden
  • Michael C. Walsh
  • H. John J. Nijkamp
  • Antoine R. Stuitje
Article

DOI: 10.1007/BF00037016

Cite this article as:
Verwoert, I.I.G.S., van der Linden, K.H., Walsh, M.C. et al. Plant Mol Biol (1995) 27: 875. doi:10.1007/BF00037016

Abstract

The Escherichia coli fabH gene encoding 3-ketoacyl-acyl carrier protein synthase III (KAS III) was isolated and the effect of overproduction of bacterial KAS III was compared in both E. coli and Brassica napus. The change in fatty acid profile of E. coli was essentially the same as that reported by Tsay et al. (J Biol Chem 267 (1992) 6807–6814), namely higher C14:0 and lower C18:1 levels. In our study, however, an arrest of cell growth was also observed. This and other evidence suggests that in E. coli the accumulation of C14:0 may not be a direct effect of the KAS III overexpression, but a general metabolic consequence of the arrest of cell division. Bacterial KAS III was expressed in a seed- and developmentally specific manner in B. napus in either cytoplasm or plastid. Significant increases in KAS III activities were observed in both these transformation groups, up to 3.7 times the endogenous KAS III activity in mature seeds. Only the expression of the plastid-targeted KAS III gene, however, affected the fatty acid profile of the storage lipids, such that decreased amounts of C18:1 and increased amounts of C18:2 and C18:3 were observed as compared to control plants. Such changes in fatty acid composition reflect changes in the regulation and control of fatty acid biosynthesis. We propose that fatty acid biosynthesis is not controlled by one rate-limiting enzyme, such as acetyl-CoA carboxylase, but rather is shared by a number of component enzymes of the fatty acid biosynthetic machinery.

Key words

Escherichia coli fatty acid synthesis 3-ketoacyl-acyl carrier protein synthase III transgenic rapeseed 

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Ira I. G. S. Verwoert
    • 1
  • Karin H. van der Linden
    • 1
  • Michael C. Walsh
    • 2
  • H. John J. Nijkamp
    • 1
  • Antoine R. Stuitje
    • 1
  1. 1.Department of Genetics, Institute for Molecular Biological Sciences, BioCentrum AmsterdamVrije UniversiteitAmsterdamThe Netherlands
  2. 2.E. C. Slater Institute, BioCentrum AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands

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