Submitted to: Journal of Lipid Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2011
Publication Date: January 1, 2012
Citation: Chapman, K.D., Dyer, J.M., Mullen, R.T., 2012. Biogenesis and functions of lipid droplets in plants. Journal of Lipid Research, 53:215-226.
Interpretive Summary: The seed oils of plants are major agricultural commodities that have traditionally been used for food and cooking applications, but inrecent years, there has been increasing usage of these oils as renewable sources of biofuels, such as biodiesel. Given the high demand for plant oils, there is considerable interest in developing ways to increase the yields of oil from plants. Achieving this goal, however, will require a better understanding of the basic biology of oil production in plants. The oils of plants are stored in small subcellular compartments called “lipid droplets”, and although these droplets were once thought to be static depots of oil reserve, it is now apparent that they are highly dynamic structures that are involved in many different aspects of plant life including stress response and plant growth and development. In this manuscript, the authors provide a summary of the current understanding of lipid droplet production and regulation, with an eye towards identifying those properties that might be manipulated to increase the total yield of oils in plants. This information will be most useful in the short run to other scientists who are interested in understanding and further exploring the basic biology of oil production in plants.
The compartmentation of neutral lipids in plant tissues is mostly associated with seed tissues, where triacylglycerols (TAGs) stored within lipid droplets (LDs) serve as an essential physiological energy and carbon reserve during post-germinative growth. However, some non-seed tissues, such as leaves, flowers and fruits, also synthesize and store TAGs, yet relatively little is known about the formation or function of LDs in these tissues. Characterization of LD-associated proteins, such as oleosins, caleosins, and sterol dehydrogenases (steroleosins), has revealed surprising features of LD function in plants, including stress responses, hormone signaling pathways, and various aspects of plant growth and development. While oleosin and caleosin proteins are specific to plants, LD-associated sterol dehydrogenases also are present in mammals, and in both plants and mammals these enzymes have been shown to be important in (steroid) hormone metabolism and signaling. In addition, several other proteins known to be important in LD biogenesis in yeasts and mammals are conserved in plants, suggesting that at least some aspects of LD biogenesis and/or function are evolutionarily conserved.