T-DNA–mediated transfer of Agrobacterium tumefaciens chromosomal DNA into plants

Backbone fragments of the Agrobacterium tumor-inducing (Ti) plasmid that bears transgenes of interest have occasionally been reported to be transferred to plant genomes. Now, Ulker et al. show that Agrobacterium chromosomal DNA can also be integrated into transgenic plants at a low frequency. Gene-bearing chromosomal fragments as large as 18 kb are found in T-DNA–tagged populations of Arabidopsis thaliana.