title: Delivery of T-DNA from the Agrobacterium tumefaciens chromosome into plant cells.
abstract: The intact T-region of the B6Ti plasmid of Agrobacterium tumefaciens was stepwise cloned into a site in transposon Tn3. In this way a suitable vehicle (Tn1882) was obtained for translocating the T-region to different replicons, i.e., to other plasmids or the chromosome. The IncP plasmid R772::Tn1882 conferred tumorigenicity on Agrobacterium if the virulence genes were provided in trans in the same cell. This result showed that the T-region present on Tn1882 was transferred efficiently to plant cells. Normal tumor development also occurred if the T-region was placed in the chromosome of A. tumefaciens and an R' plasmid was present carrying virA-E or virA-F. We conclude that the plasmid location of the T-region is not a prerequisite for transfer to the plant cell. The apparently normal delivery of the T-DNA from a bacterial chromosomal location supports a model involving a processing step within Agrobacterium effecting transfer of the T-region as a separate entity.
authors.affiliation: Molbas Research Group, Department of Plant Molecular Biology, University of Leiden, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Hoekema
authors.forename: P W
authors.initials: PW
authors.lastname: Roelvink
authors.forename: P J
authors.initials: PJ
authors.lastname: Hooykaas
authors.forename: R A
authors.initials: RA
authors.lastname: Schilperoort