A major
wound response in grand fir (Abies grandis) sapling stems is the rapid increase in
monoterpene production at the site of injury.
Monoterpene cyclases (synthases) catalyze the formation of
monoterpenes from
geranyl pyrophosphate, and total cyclase activity increases markedly on wounding. At least six distinct cyclases, producing different
monoterpene products, have been isolated from wounded grand fir saplings and characterized. The predominant
wound-inducible cyclase produces both alpha- and
beta-pinene. This
pinene cyclase was purified, and polyclonal
antibodies were generated in rabbits against the
sodium dodecyl sulfate-denatured
protein. The antibody preparation was found to cross-react by Western blotting with other grand fir
monoterpene cyclases that produce different olefinic products, but not with
monoterpene cyclases from related conifer species (Pinus contorta and P. ponderosa) or from angiosperms (Mentha piperita and M. spicata). The increase in
monoterpene cyclase activity after wounding was closely correlated with the appearance of new cyclase
protein as determined by immunoblotting. These results indicate that the
wound-dependent increase in
monoterpene cyclase activity is a consequence of de novo synthesis of cyclase
protein.