Abstract: cDNAs encoding gymnosperm monoterpene synthases have been isolated and sequenced, and the corresponding amino acid sequences have been determined. Modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding a monoterpene synthase of the invention. Thus, systems and methods are provided for the recombinant expression of recombinant monoterpene synthases that may be used to facilitate their production, isolation and purification in significant amounts.