DIRECT REGENERATION IN-VITRO AND TRANSIENT GUS EXPRESSION IN MENTHA XPIPERITA

Genetic transformation of peppermint is known to be very difficult ess entially because of low efficiency regeneration. A regeneration protoc ol allowing 51% shooting frequency is proposed. Transient beta-glucuro nidase expression and adjustment of selection pressure with kanamycin are also reported. The final retained method to attempt peppermint tra nsformation is: Agrobacterium inoculation or biolistic treatment of th e first apical leaves of in vitro clones, regeneration in the dark wit h kanamycin (1 mg l(-1)) and 6-benzylaminopurine (2 mg l(-1)), followe d by selection of regenerated shoots with 200 mg l(-1) kanamycin.