The Oxygen-Dependent Modification of Triacylglycerols and Phospholipids, the Different Way of Initiating Lipid Body Mobilization

Abstract

For plant seedlings dependent on the breakdown of lipid reserves for gluconeogenesis the onset of lipid mobilization is a critically important process. Until recently, knowledge about the chemical mechanism of the initial breakdown steps has been limited, because the lipolytic activities, characterized by the intracellular localization and the type of substrate, have not always been found. As seedlings that depend on the reserves in lipid bodies may differ in morphology and biochemistry, it is likely that more than one pathway exists. Recent studies with cucumber (Cucumis sativus) cotyledons have shown that a lipid body-associated lipoxygenase, and an O2-dependent reaction, initiate both the destabilization of the phospholipid monolayer and the breakdown of triglycerides. Both types of reactions rely on the particular properties of a lipoxygenase isoform exclusively present in lipid bodies.