Transgenic caraway, Carum carvi L.: a model species for metabolic engineering.

Regeneration in caraway was obtained via two different routes. Hypocotyls showed delayed shoot formation after a callus phase and at relatively low frequencies. In contrast, high-frequency, direct regeneration occurred when cotyledonary node explants were used. Transient expression of β-glucuronidase was monitored after inoculation of both explant types with Agrobacterium tumefaciens AGL0(pMOG410). Gene transfer was more efficient when using cotyledonary node explants. This explant type also proved to be the best for stable transformation resulting in transgenic plants. Several parameters determining regeneration and transformation efficiency were tested. The percentage of explants giving one to numerous transgenic plants could be as high as 13%. This system for the rapid production of many transgenic caraway plants opens up possibilities for studying metabolic engineering with this crop.