A Novel Lipid Pathway Makes Massive Quantity of Surface Wax on Bayberry Fruit
Pathway gives metabolic engineers new tools for producing high-value lipids.
Bayberry fruits produce the highest amount of surface wax known in nature. Recent biochemical and gene expression data have revealed a novel biosynthesis pathway for the waxy layer that is more closely related to cutin biosynthesis than conventional triacylglyceride biosynthesis.
The discovery of how the Bayberry fruit produces massive amounts of unique surface wax aids in understanding the plant’s mechanism for producing and secreting nonmembrane glycerolipids and suggests ways to engineer pathways for high-value waxy lipid production in biomass crops.
Scientists from the Department of Energy’s (DOE) Great Lakes Bioenergy Research Center (GLBRC) studied how Bayberry fruits accumulate massive quantities of a unique surface wax with a structure similar to triacylglycerol seed oils. Research on plants that produce such large amounts of surface lipids is providing insights into the molecular features and biochemical pathways for plant lipid secretion and thus may help in developing strategies to engineer lipid production in non-seed tissues. The GLBRC scientists examined changes in fruit anatomy and details of the chemical structures secreted by Bayberry fruits, and quantified the accumulation of wax through fruit development. Biochemical pathway analysis by [14C]-labeling and transcript analysis by RNA-seq revealed features of Bayberry wax accumulation that are distinctly different from conventional triacylglycerol production. Together, these results indicate that the extracellular glycerolipids in Bayberry wax are synthesized by a novel pathway that differs from previously defined triacylglycerol biosynthesis pathways. An increased understanding of this process may prove useful in engineering plants for secretion of high-energy and high-value lipids, particularly those that have toxic or negative consequences when accumulated inside cells.
Michigan State University
This work was funded by GLBRC (DOE, Office of Science, Office of Biological and Environmental Research DE-FC02-07ER64494) and a National Science and Engineering Research Council of Canada postgraduate fellowship (PGS-D3).
Simpson, J. P., and J. B. Ohlrogge. 2016. “A Novel Pathway for Triacylglycerol Biosynthesis Is Responsible for the Accumulation of Massive Quantities of Glycerolipids in the Surface Wax of Bayberry (Myrica pensylvanica) Fruit,” The Plant Cell 28(1), 248–64. DOI: 10.1105/tpc.15.00900.