The shikimate pathway, a collection of seven enzymatic reactions whose
end product is chorismate, has been studied for many years in a varie
ty of microorganisms and plants. In microbial systems, the end product
of the pathway is used primarily for the synthesis of aromatic amino
acids. In plants, chorismate is the precursor not only for the synthes
is of aromatic amino acids, but also for many secondary metabolites wi
th diverse physiological roles. Because of the dual involvement of the
shikimate pathway in primary and secondary metabolism, there are long
-standing questions regarding its subcellular location, and its potent
ial coordinate regulation with other pathways that use chorismate or i
ts products in response to environmental or developmental demands.