The transfer of exogenous DNA into crop plants using genetic engineering techniques offers exciting possibilities for the faster transfer of genes than has hitherto been possible using conventional hybridisation techniques. Prerequisites for successful plant transformation are techniques for the regeneration of whole plants from tissue explants, a suitable gene/vector system, a selection system for identifying the transformants and access to potentially useful genes.
For Rubus (red raspberry, blackberry and red raspberry x blackberry hybrids) and Ribes we report the development of systems for plantlet regeneration from leaf discs and internodal stem segments and the use of a strain of Agrobacterium tumefaciens with the binary vector PBI121.X to transfer the marker gene beta-glucuronidase (GUS). Our current work aims to insert the cowpea trypsin inhibitor gene, which is expected to confer resistance to chewing insects, and also a virus satellite which is expected to attenuate symptom expression if the plant is infected with arabis mosaic virus.