How does agrobacterium work?

Answer 1

Using agrobacterium is the most common way of genetically modifying plants.

Inside the bacterium there is a circular piece of DNA called a plasmid, which also has a chromosome. This TI plasmid is tumor inducing but it transfers the plasmid DNA by infecting the plants DNA (it cuts the chromosome of the plant and inserts the plasmid). The bacterium live inside the tumor of the plant.

Scientists tooks the T dna, removed the tumor causing genes, and left the DNA splicing genes. They then use the bacterium to transfer the DNA they want.