Antisense-mediated reduction in ADC activity causes minor alterations in the alkaloid profile of cultured hairy roots and regenerated transgenic plants of Nicotiana tabacum

It is shown that although expression of an antisense ADC cDNA sequence in hairy roots of tobacco results in markedly diminished ADC activity, only small reductions in nicotine content are observed and anatabine:nicotine ratios are only slightly elevated in antisense-ADC hairy root lines and regenerated transgenic plants compared to controls. These observations suggest that the level of ADC activity in tobacco roots is not normally the major determinant that ensures adequate levels of putrescine are available for nicotine synthesis.