Terpenoids are a class of chemicals with over 50,000 individual compounds,
highly diverse in chemical structure, founded in all kingdoms of life, and are the largest
group of secondary plant metabolites. Also known as isoprenoids, their structure began
to be elucidated between the 1940s and 1960s, when their basic isoprenoid building
blocks were characterized. They play several basic and specialized physiological
functions in plants through direct and indirect interactions. Terpenoids are essential to
metabolic processes, including post-translational protein modifications, photosynthesis,
and intracellular signaling. All terpenoids are built through C5
units condensed to
prenyl diphosphate intermediates. The fusion of these C5
units generates short C15-C25,
medium C30-C35, and long-chain C40-Cn terpenoids. Along with the extension of the
chain, the introduction of functional groups, such as ketones, alcohol, esters and,
ethers, forms the precursors to hormones, sterols, carotenoids, and ubiquinone
synthesis. The biosynthesis of terpenoids is regulated by spatial, temporal,
transcriptional, and post-transcriptional factors. This chapter gives an overview of
terpenoid biosynthesis, focusing on both cytoplasmic and plastid pathways, and
highlights recent advances in the regulation of its metabolic pathways.
Keywords: Abscisic Acid, Brassinosteroids, Carotenoids, Dimethylallyl Diphosphate, Gene Regulation, Gene Expression, Glycosylation, Isopentenyl Diphosphate, Isoprene, Isoprenoids, MEP Pathway, MVA Pathway, Plant Hormones, Prenyl Diphosphate, Secondary Metabolites, Sterols, Terpene Synthesis, Terpenoid, Ubiquinone, Volatile Terpenes.
