Genetic transformation of 9 in vitro clones of Alnus and Betula by Agrobacterium tumefaciens.

Crown gall tumorigenesis, integration and expression of T-DNA encoded genes from Agrobacterium tumefaciens were investigated in 9 clones of Alnus glutinosa, A. incana and Betula papyrifera. Tumor formation on in vitro shoots was frequent in all clones with strain Ach5 and present in 8 clones with strain C58. Tumors excised from shoots were selected for autotrophic growth in vitro and axenic cultures were established. Octopine or nopaline, respective of the strain type used for inoculation, was detected in tumorous cultures. Southern blot analyses demonstrated T-DNA integration by hybridization of DNA from tumors with tmr and nos gene probes. One clone of B. papyrifera produced tumors with a morphogenic character, unusual in calli of this species, generating viable shoots which did not synthesize opine.