T-DNA Binary Vectors and Systems

For more than two decades, scientists have used Agrobacterium-mediated genetic transformation to generate transgenic plants. Initial technologies to in- troduce genes of interest (goi) into Agrobacterium in- volved complex microbial genetic methodologies that inserted these goi into the transfer DNA (T-DNA) re- gion of large tumor-inducing plasmids (Ti-plasmids). However, scientists eventually learned that T-DNA transfer could still be effected if the T-DNA region and the virulence (vir) genes required for T-DNA process- ing and transfer were split into two replicons. This binary system permitted facile manipulation of Agro- bacterium and opened up the field of plant genetic engineering to numerous laboratories. In this review, we recount the history of development of T-DNA binary vector systems, and we describe important components of these systems. Some of these consider- ations were previously described in a review by Hellens et al. (2000b).