Increase in lysophosphatidate acyltransferase activity in oilseed rape (Brassica napus L.) increases seed triacylglycerol content despite its low intrinsic flux control coefficient

Woodfield, Helen K.; Fenyk, Stepan; Wallington, Emma; Bates, Ruth E.; Brown, Alexander; Guschina, Irina A.; Marillia, Elizabeth-France; Taylor, David C.; Fell, David; Harwood, John L.; Fawcett, Tony

Abstract

Lysophosphatidate acyltransferase (LPAAT) catalyses the second step of the Kennedy pathway for triacylglycerol (TAG) synthesis. Here we express Trapaeolum majus LPAAT in Brassica napus (B. napus) cv 12075 to evaluate the effects on lipid synthesis and estimate the flux control coefficient for LPAAT. We estimate the flux control coefficient of LPAAT in a whole plant context by deriving a relationship between it and overall lipid accumulation, given that this is an exponential process. Increasing LPAAT activity resulted in greater TAG accumulation in seeds of between 25 and 29%; altered fatty acid distributions in seed lipids (particularly those of the Kennedy pathway); and a redistribution of label from 14C‐glycerol between phosphoglycerides. Greater LPAAT activity in seeds led to an increase in TAG content despite its low intrinsic flux control coefficient on account of the exponential nature of lipid accumulation that amplifies the effect of the small flux increment achieved by increasing its activity. We have also developed a novel application of metabolic control analysis likely to have broad application as it determines the in planta flux control that a single component has upon accumulation of storage products.

Citation

Woodfield, H. K., Fenyk, S., Wallington, E., Bates, R. E., Brown, A., Guschina, I. A., …Fawcett, T. (2019). Increase in lysophosphatidate acyltransferase activity in oilseed rape (Brassica napus L.) increases seed triacylglycerol content despite its low intrinsic flux control coefficient. New Phytologist, 224(2), 700-711. https://doi.org/10.1111/nph.16100

• Journal Article Type: Article
• Acceptance Date: Jul 23, 2019
• Online Publication Date: Sep 14, 2019
• Publication Date: Oct 31, 2019
• Deposit Date: Aug 2, 2019
• Publicly Available Date: Sep 17, 2019
• Journal: New Phytologist
• Print ISSN: 0028-646X
• Electronic ISSN: 1469-8137
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 224
• Issue: 2
• Pages: 700-711
• DOI: https://doi.org/10.1111/nph.16100
• Public URL: https://durham-repository.worktribe.com/output/1326173