Using lipidomics to reveal details of lipid accumulation in developing seeds from oilseed rape (Brassica napus L.)

Helen K Woodfield,Amaury Cazenave-Gassiot,Richard P Haslam,Irina A Guschina,Markus R Wenk,John L Harwood

doi:10.1016/j.bbalip.2017.12.010

Abstract

With dwindling available agricultural land, concurrent with increased demand for oil, there is much current interest in raising oil crop productivity. We have been addressing this issue by studying the regulation of oil accumulation in oilseed rape (Brassica napus L). As part of this research we have carried out a detailed lipidomic analysis of developing seeds.The molecular species distribution in individual lipid classes revealed quite distinct patterns and showed where metabolic connections were important. As the seeds developed, the molecular species distributions changed, especially in the period of early (20days after flowering, DAF) to mid phase (27DAF) of oil accumulation. The patterns of molecular species of diacylglycerol, phosphatidylcholine and acyl-CoAs were used to predict the possible relative contributions of diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase to triacylglycerol production. Our calculations suggest that DGAT may hold a more important role in influencing the molecular composition of TAG. Enzyme selectivity had an important influence on the final molecular species patterns.Our data contribute significantly to our understanding of lipid accumulation in the world's third most important oil crop.

Highlights

Plant oils are major agricultural commodities with a current market value of over US$120 billion [1]
A mid-point at 27 days after flowering (DAF) was selected and analyses made of the accumulating TAG, the important metabolic intermediates, DAG, PA, and PC, as well as the second most prevalent seed phosphoglyceride (PE) as a comparator
The data reported here describe lipidomic analysis of major lipids involved in TAG formation in the major oil crop, B. napus

Summary

Introduction

Plant oils are major agricultural commodities with a current market value of over US$120 billion [1] Demand for such oils has been increasing at about 5% per year for the last five decades [2]. We have studied the regulation of oil accumulation in crops, partly by the application of flux control analysis [10,11,12,13] These experiments have revealed important overall characteristics of the process but often could not delineate some of the details such as the subsidiary flux of fatty acids from the basic Kennedy pathway into and out of phosphatidylcholine (PC), either in terms of polyunsaturated fatty acid production [14,15] or via phospholipid:diacylglycerol acyltransferase (PDAT) [16]. Since modern lipidomics is useful for identifying metabolic networks and testing hypotheses about control [17] we have used it here to elucidate details of metabolism and further our knowledge of regulation

Methods

Results

Discussion

Conclusion