Transformation of woody species: State of the art

The transformation of woody crop species does not differ from the transformation of herbaceous plants by the technical approach, but by its feasibility and by the natural longevity of perennial plants. There is also relatively little information available concerning the characterization of transformed woody plants. The crucial role of the explant and the most commonly used transformation methods are highlighted. The breeding and cultivation of virus resistant plants represents a major contribution to the control of viral diseases, since there do not exist chemical control strategies. The genetic engineering approach to virus resistance breeding chosen at the IAM and some recent results are presented. At the IAM over hundred apricot, plum, cherry and grapevine lines have been transformed with different sequences of the Plum Pox Virus, the Prunus Necrotic Ringspot Virus, different grapevine viruses, e.g. GFLV, ArMV, GVA and GVB, and various marker genes. Vectors were constructed under particular consideration of safety aspects. Efforts undertaken to create public acceptance are briefly introduced. Perspectives for the future application of the technology will be given.