A clone encoding farnesyl diphosphate synthase (FPPS) was obtained by PCR from a cDNA library made from young leaves of Artemisia annua. A cDNA clone encoding the tobacco epi‐aristolochene synthase (eAS) was kindly supplied by J. Chappell (University of Kentucky, Lexington, KY, USA). Two fusions were constructed, i.e. FPPS/eAS and eAS/FPPS. The stop codon of the N‐terminal enzyme was removed and replaced by a short peptide (Gly‐Ser‐Gly) to introduce a linker between the two ORFs. These two...