Control of Isoprenoid Biosynthesis in Higher Plants

Publisher Summary Higher plants contain a bewildering array of isoprenoid compounds with a wide variety of structures and functions. In higher plants, many of these isoprenoid compounds play vital roles in the metabolism and development of the plant. The plant growth regulators, abscisic acid and gibberellins, are isoprenoid compounds and many cytokinins contain an isoprenoid side chain. Isoprenoid side chains are also found in many other biologically active molecules; including chlorophylls, plastoquinone, and other prenylquinones in chloroplasts, where together with carotenoids they are involved in photosynthesis. Isoprenoid side chains are also found in the mitochondria1 electron transfer chain components, ubiquinone, and haem α of cytochrome oxidase. Plants must be able to produce this wide range of isoprenoid compounds in different amounts in different parts of the plant at different stages of growth and development. As all these compounds are produced by a common biosynthetic pathway, the plant must have exquisite control mechanisms to ensure the synthesis of the necessary compounds in the right place at the right time. This chapter considers the knowledge of the control of isoprenoid biosynthesis in higher plants, particularly with respect to the properties and subcellular locations of the enzymes involved.