The diverse functions of plant lipid droplets

Prof. Dr. Till Ischebeck

Institute for Plant Biology and Biotechnology, University of Münster

Lipid droplets (LDs, also referred to as oil bodies or oleosomes) are subcellular structures that consist of proteins attached to or embedded in a phospholipid monolayer surrounding a hydrophobic core of mostly triacylglycerol. In plants, LDs occur not only in seeds and pollen but also in vegetative tissues, where they accumulate under stress. This accumulation has also been described in algae, where LDs can be very prominent. We are especially interested in the proteins associated with LDs. In this context, we have studied the composition across a number of species and tissues and under different environmental conditions by combining proteomic and cell biological approaches. Through this, we identified several proteins involved in specialized metabolism but also proteins that were previously of unknown function.
For example, we could show that a triacyl glycerol lipase is involved in volatile production through a pathway that includes the peroxidation of fatty acids. We also found that LDs are a hot spot for triterpene synthesis and storage. Three further proteins we characterized form an LD-plasma membrane (PM) tethering complex in plant cells that is important for LD positioning during embryogenesis and seedling establishment. Having worked mostly in Arabidopsis, we are now also studying how the composition and function of LDs changed throughout evolution studying streptophyte algae, bryophytes and ferns.