A branched pathway that produces the precursors to four structurally distinct types of polycyclic diterpenes. The pathway starts with the cyclization of geranylgeranyl diphosphate into ent-copalyl diphosphate and syn-copalyl diphosphate. The catalytic conversion by diterpene cyclases of these two compounds produces the four diterpene hydrocarbons which are precursors to the four structurally distinct classes of diterpene phytoalexins.
diterpene phytoalexin precursor synthesis pathway