Integration ofAgrobacterium tumefaciens transfer DNA (strongTstrong-DNA).pdfVIP

Proc. Nadl. Acad. Sci. USA Vol. 84, pp. 6169-6173, September 1987 Botany Integration ofAgrobacterium tumefaciens transfer DNA (T-DNA) involves rearrangements of target plant DNA sequences (Nicotiana tabacum) GODELIEVE GHEYSEN, MARC VAN MONTAGU*, AND PATRICIA ZAMBRYSKIt Laboratorium voor Genetica, Rijksuniversiteit Gent, B-9000 Gent, Belgium Contributed by Marc Van Montagu, May 26, 1987 ABSTRACT The transfer DNA (T-DNA) mobilized into within the bottom strand on the Ti plasmid (8-10). Border plant cells by Agrobacterium tumefaciens seems to integrate nicks have been proposed to represent initiation (right bor- rather randomly into the plant genome. We analyzed a target der) and termination (left border) sites for T-strand synthesis site in the genome of Nicotiana tabacum before and after (8). The specific properties ofthe T-strand molecule have led integration of a T-DNA. Clones presenting right and left to the formation of a model for the mechanism of T-DNA T-DNA/plant DNA junctions were used as probes to identify transfer to plant cells analogous to bacterial conjugation (8, and isolate a unique 1.8-kilobase EcoRI fragment correspond- 11). ing to the plant DNA target site for a T-DNA insertion event. While some of the early bacterial reactions that lead to Comparison of the nucleotide sequences of the plant DNA T-DNA transfer are beginning to be understood, little is portions of the T-DNA junction clones with the original plant known about later events that lead to T-DNA integration into DNA target revealed that several types of rearrangements the plant nuclear genome. To date, analyses have been resulted from insertion of the T-DNA. The most dramatic limited to sequence determinati