Secondary metabolite production by plant cell cultures has been the subject of many investigations. Indole alkaloids such as ajmalicine, an antihypertensive drug, or vinblastine and vincristin, two antitumor compounds produced by Catharanthus roseus, are very important in the pharmaceutical industry. Cell cultures from the same plant species have been propagated in several laboratories since they are expected to produce physiologically potent indole alkaloids (Carew 1975). Undifferentiated cell lines producing high yields of ajmalicine, or serpentine, that can be easily converted into ajmalicine by reduction, have been obtained by selection (Zenk et al. 1977).

We have analyzed opine content, T-DNA content, and developmental features of one hairy root culture line and its progeny. Opine-positive progeny still have the hairy root phenotype and have essentially the same T-DNA structure as the parental plant. Opineless progeny do not exhibit the hairy root phenotype. Some of them do not contain any T-DNA sequences, whereas others contain only the left part of T-DNA. These results are compatible with the hypothesis that, in the hairy root line analyzed, the left part of T-DNA is integrated independently from the core T-DNA and can therefore segregate during sexual reproduction.