DNA from Ti plasmid present in nucleus and absent from plastids of crown gall plant cells

Abstract

The Gram-negative soil bacterium Agrobacterium tumefaciens induces crown gall tumours on most dicotyledonous plants1,2, its Ti plasmids causing the neoplastic transformation of plant cells3-5. Molecular hybridization has shown that transformed cells contain a segment of the Ti plasmid (T-DN A) of molecular weight 8-15 × 106 (refs 6-9), of which at least part is transcribed10,11. Some copies of the T-DNA are integrated into the plant DNA (unpublished work). In view of the prokaryotic origin of the T-DNA, the possibility of its localization within either mitochondria or chloroplasts must be considered. We present here evidence for the absence of T-DNA from mitochondria and chloroplasts. Our results clearly show its presence within the nucleus. © 1980 Nature Publishing Group.