[3] These compounds play important roles in conifers as the second line of defense against insect induced trauma and fungal pathogens.

It was thought to contain a mixture of JH-mimicking sesquiterpenes, but it wasn't until 1966 that (+)-juvabione was first isolated as an active component from the balsam fir by Bowers.

Abies balsamea Insect herbivores such as bark beetles and their symbiotic fungal pathogens, pose as one of the greatest threats to conifer survival.

These provide a volatile solvent for the diterpene resins so that successive evaporation leaves a barrier that seals the wound site.

This product then condenses with third molecule of acetyl-CoA in a stereospecific fashion to form 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) which then is reduced to mevalonic acid (MVA).

Electrophilic addition of another IPP unit to the GPP cation results in a tertiary carbocation intermediate that forms a fifteen-carbon farnesyl diphosphate (FPP) upon loss of a proton.

NPP is another precursor that can undergo different reaction types, but in this case, bisabolene synthase directs a single cyclization event by electrophilic attack of C-1 onto the double bond of C-6 to form a six-membered ring.