Nature’s assembly line: biosynthesis of simple phenylpropanoids and polyketides

Abstract

SummaryPlants produce large amounts of phenylpropanoids, both in terms of molecular diversity and absolute quantity of these compounds. The phenylpropanoids, and the related plant polyketides, have multiple biological functions. They serve to attract pollinators, support secondary cell-wall growth, provide protection against various plant diseases, and interact with beneficial soil microbes. Their basic chemical properties also make them useful in the biofuel and biomaterial industries. Phenylpropanoid metabolism begins with the amino acid phenylalanine, which feeds into various biosynthetic pathways that generate a wide range of structurally related polyphenolic compounds. This review focuses on four sub-groups of these polyphenolic compoundspolyketides, stilbenes, isoflavones and catechins. We discuss the biosynthesis of these molecules, their physiological role in plants, and their striking pharmacological and physiological effects on humans. This review also highlights metabolic engineering efforts aimed at increasing or decreasing the amounts of each class of compound in various model plants and crops.

Structural Evolution of Differential Amino Acid Effector Regulation in Plant Chorismate Mutases

“…Chorismate lies at an important branch point in the synthesis of aromatic amino acids and multiple specialized metabolites that contain aromatic groups (1)(2)(3)(4)(5). The enzymes that function at this branch point, including chorismate mutase, are tightly regulated.…”

“…For example, the effector site of Saccharomyces cerevisiae chorismate mutase (ScCM) 3 can bind either tryptophan or tyrosine (10). Tryptophan binding activates ScCM, and tyrosine leads to attenuation of prephenate synthesis.…”

Identification of olivetolic acid cyclase from Cannabis sativa reveals a unique catalytic route to plant polyketides

“…The current model of plant polyketide biosynthesis is that carbon scaffolds are assembled exclusively by the activity of type III PKS enzymes (37). The discovery of OAC indicates a variant catalytic route in plants in which cyclase enzymes function cooperatively with type III PKSs.…”

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases

“…These represent a significant proportion of secondary metabolites, encompassing nearly 20% of total carbon in the terrestrial biosphere. Flavonoids exhibit remarkable chemical diversity and ubiquitous occurrence and play an important role in many aspects of plant development, like flower coloration, photoprotection, pollen development, cell wall growth, and response to stress conditions like UV light protection, herbivory, wounding, interaction with soil microbes, and defense against pathogens (Yu and Jez, 2008;Pandey et al, 2015). Apart from performing numerous imperative roles in plants, flavonoids also have been reported as potent phytoceuticals with putative health benefits (Jiang et al, 2015).…”