Genetic manipulation of lipoxygenases for the agrifood industry

Abstract

Lipoxygenases (LOX) are a group of non-haem iron-containing enzymes that are widely distributed within Nature and can be found in algae, fungi, animals and plants. In animals they are recognized as catalyzing the first step on the pathway from arachidonic acid to leukotrienes, important compounds that mediate inflammatory and allergic responses. In plants, they were for a long time considered to be an enigma, but now have clearly-defined roles in defence reactions, may be involved in apoptosis, have a role in metabolic homeostasis and also influence the quality of foods in several ways. This article describes: the multiplicity of LOX in plants; the significance of such multiplicity in terms of generation of different fatty acid hydroperoxides; the various ways in which these hydroperoxides are metabolized; the ways in which we have attempted to manipulate the amounts of LOX in plants and what this has told us; and the consequent “balancing act” that needs to be performed, between our perceived requirements in terms of food quality and the requirements of plants in terms of growth, development and health.