Phenylpropanoid metabolism and lignin biosynthesis: From weeds to trees

Vascular plants have the unique ability to divert large amounts of carbon from aromatic amino acid metabolism into the biosynthesis of products based on a phenylpropane skeleton. These diverse phenylpropanoid compounds - which include flavonoids, lignin, coumarins and many small phenolic molecules - have a multiplicity of functions in structural support, pigmentation, defense and signaling. It is likely that the evolution of phenylpropanoid pathways played a key role in the ability of plants to colonize land; furthermore, many agricultural and forestry-related plant properties are associated with phenylpropanoid products. Recent molecular and genetic experiments have cast light on the mechanisms that regulate the biosynthesis of phenylpropanoids, and show that the exciting prospect of being able to manipulate lignin biosynthesis is a realistic possibility.