Sulfolipid Biosynthesis and Function in Plants

Abstract

The plant sulfolipid sulfoquinovosyldiacylglycerol accounts for a large fraction of organic sulfur in the biosphere. Aside from sulfur amino acids, sulfolipid represents a considerable sink for sulfate in plants. Plant sulfolipid is found in the photosynthetic membranes of plastids and provides negative charge in the thylakoid membrane where it is thought to stabilize photosynthetic complexes. As the plant sulfolipid is a non-phosphorous glycolipid, its synthesis does not impinge on the supply of phosphate, which is a macronutrient limiting plant growth in many natural environments. Indeed, plants evolved homeostatic mechanisms to balance the amount of sulfolipid with anionic phospholipids maintaining a proper level of anionic charge in the photosynthetic membrane. The strong anionic nature of the sugar sulfonate head group of sulfolipid also makes this lipid an interesting compound for biotechnological applications. As bacterial and plant genes encoding sulfolipid enzymes are now available, biotechnological approaches can be developed to produce the plant sulfolipid in sufficient amounts to pursue the development of practical applications.