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The cDNA from Nicotiana tabacum encoding Putrescine N-methyltransferase (PMT), which catalyzes the first committed step in the biosynthesis of tropane alkaloids, has been introduced into the genome of a scopolamine-producing Hyoscyamus niger mediated by the disarmed Agrobacterium tumefaciens strain C58C1, which also carries Agrobacterium rhizogenes Ri plasmid pRiA4, and expressed under the control of the CaMV 35S promoter. Hairy root lines transformed with pmt presented fivefold higher PMT activity than the control, and the methylputrescine (MPUT) levels of the resulting engineered hairy roots increased four to fivefold compared to the control and wild-type roots, but there was no significant increase in tropane alkaloids. However, after methyl jasmonate (MeJA) treatment, a considerable increase of PMTase and endogenous H6Hase as well as an increase in scopolamine content was …