Metabolic control analysis of developing oilseed rape (Brassica napus cv Westar) embryos shows that lipid assembly exerts significant control over oil accumulation
Article first published online: 20 AUG 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 196, Issue 2, pages 414–426, October 2012
How to Cite
Tang, M., Guschina, I. A., O’Hara, P., Slabas, A. R., Quant, P. A., Fawcett, T. and Harwood, J. L. (2012), Metabolic control analysis of developing oilseed rape (Brassica napus cv Westar) embryos shows that lipid assembly exerts significant control over oil accumulation. New Phytologist, 196: 414–426. doi: 10.1111/j.1469-8137.2012.04262.x
- Issue published online: 17 SEP 2012
- Article first published online: 20 AUG 2012
- Received: 23 April 2012, Accepted: 1 July 2012
- lipid biosynthesis;
- oilseed rape (Brassica napus);
- seed oil accumulation;
- top-down control analysis;
- triacylglycerol formation
- •Metabolic control analysis allows the study of metabolic regulation. We applied both single- and double-manipulation top-down control analysis to examine the control of lipid accumulation in developing oilseed rape (Brassica napus) embryos.
- •The biosynthetic pathway was conceptually divided into two blocks of reactions (fatty acid biosynthesis (Block A), lipid assembly (Block B)) connected by a single system intermediate, the acyl-coenzyme A (acyl-CoA) pool. Single manipulation used exogenous oleate. Triclosan was used to inhibit specifically Block A, whereas diazepam selectively manipulated flux through Block B.
- •Exogenous oleate inhibited the radiolabelling of fatty acids from [1-14C]acetate, but stimulated that from [U-14C]glycerol into acyl lipids. The calculation of group flux control coefficients showed that c. 70% of the metabolic control was in the lipid assembly block of reactions. Monte Carlo simulations gave an estimation of the error of the resulting group flux control coefficients as 0.27 ± 0.06 for Block A and 0.73 ± 0.06 for Block B.
- •The two methods of control analysis gave very similar results and showed that Block B reactions were more important under our conditions. This contrasts notably with data from oil palm or olive fruit cultures and is important for efforts to increase oilseed rape lipid yields.