REGENERATION AND TRANSFORMATION OF EUCALYPTUS-CAMALDULENSIS

Reliable regeneration protocols for Eucalyptus camaldulensis using lea f explants from in vitro-grown plants have been developed. Out of the 24 clones tested 13 were regenerated and of these, 6 showed regenerati on from more than 60% of the explants. Identical protocols were also s uccessful in the regeneration of some clones of E. microtheca, E. ochr ophloia, E. grandis and E. marginata, but at lower frequencies. Co-cul tivation of E. camaldulensis leaf explants with Agrobacterium tumefaci ens strains carrying a kanamycin resistance gene and the reporter gene beta-glucuronidase (GUS), followed by selection on kanamycin at 9 mg l(-1), allowed the selection of transformed shoots that could be roote d on selective media. Transformation of the plants was verified by sta ining for the GUS enzyme in various plant tissues, NptII assays and by Southern blotting on isolated DNA using specific probes for both the GUS and selectable marker genes. Transformed tissue was obtained with 5 clones of E. camaldulensis tested and a number of A. tumefaciens str ains. However, only 1 clone regenerated transformed whole plants relia bly.