Equipe Physiologie Horticulture Biotechnologie végétale, Laboratoire de Recherche Forestière, Faculté des Sciences, Université de Lomé, 01 BP 1515 Lomé 01, Togo
Investigations have been carried out with the aim of producing secondary metabolites in vitro by cell cultures of Zanthoxylum zanthoxyloides. Cell dedifferentiation from explants was induced in the presence of 2,4-dichlorophenoxyacetic acid or 1-naphthaleneacetic acid in combination with benzyladenine. HPLC analyzes revealed the uneven accumulation, in diversity and quantity, of a number of secondary metabolites in these cell cultures. These secondary metabolites are not synthesized by all cell strains with the exception of hesperidin which is present everywhere. Quantification of hesperidin and chelerythrine showed that 2,4-dichlorophenoxyacetic acid inhibits their synthesis unlike 1-naphthaleneacetic acid and light which seem to stimulate it. This study shows that it is possible to produce secondary compounds in vitro by cell cultures of Zanthoxylum zanthoxyloides.
Literature reports that roots are source of important compounds possessing pharmaceutical properties. So, we have oriented our work toward the transgenic root establishment of O. basilicum obtained from Agrobacterium rhizogenes, a natural bacterium of the soil responsible for the formation of the "hairy root". This genetic transformation was achieved from the leaves and segments of stems allowed to initiate of abundant roots, displaying the typical characteristics of the hairy root syndrome, as a rapid growth on solid and in liquid media without hormones. The root initiation seems to arise from the target cells near to the inner and outer phloem after mother plant infection. A bacterial inoculation at the central nervure level of the leaves led to an efficient and original protocol of transformation. Indeed numerous transgenic root clones, from Ocimum explants, could be obtained. Finally, the transformed state of the roots was confirmed by molecular analysis showing the obvious integration of the genes rol of A. rhizogenes responsible of the "hairy root" phenotype.