Agrobacterium tumefaciens
Agrobacterium is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. "Agrobacterium tumefaciens" is the most commonly studied species in this genus. "Agrobacterium" is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering.