Plant Sphingolipids

Abstract Sphingolipids, a class of amino alcohol‐based lipids, are major eukaryotic lipids, and they have also been found in some prokaryotes. Since the discovery of sphingolipids by Johann Ludwig Thudichum in 1874, this class of lipids is now less enigmatic, and to date, we have a much better understanding of how they are metabolised, their structural diversity and the roles they play in regulating eukaryotic cellular processes and physiology. Our understanding of the functional roles of sphingolipids in cells has come largely from studies using mammalian cells and yeast. However, in the past 20 years, we have made great strides in our understanding of plant sphingolipid metabolism, structure and function. Readers are encouraged to refer to the relevant literature for further detailed information. Key Concepts Sphingolipids are major eukaryotic lipids, and they have been shown to be important in membrane organisation, as well as playing key roles in regulating cellular physiology. The de novo biosynthesis of sphingolipids in all eukaryotes begins in the endoplasmic reticulum (ER) and is catalysed by the pyridoxal 5′‐phosphate (PLP)‐dependent serine palmitoyltransferase (SPT), resulting in the formation of long‐chain bases (LCBs). The LCBs can undergo further metabolism to form more complex sphingolipids, such as ceramides, glucosylceramides and glycosyl inositolphosphoceramides (GIPCs). In addition to the de novo pathway, all eukaryotes also possess the salvage pathway whereby LCBs are recovered from ceramides, and key to this salvage pathway is a class of enzymes known as ceramidases. Plant sphingolipids have been shown to function in membrane organisation, abiotic and biotic stress responses, regulation of developmental processes and plant physiology.