Transfer DNA binary system

A transfer DNA (T-DNA) binary system is a pair of plasmids consisting of a binary plasmid and a helper plasmid. The two plasmids are used together (thus binary) to produce genetically modified plants. They are artificial vectors that have both been created from the naturally occurring Ti plasmid found in Agrobacterium tumefaciens. The binary vector is a shuttle vector, so-called because it is able to replicate in multiple hosts (E. coli and Agrobacterium tumefaciens).