The Ti (tumor-inducing) plasmid used for producing transgenic plants is found in "Agrobacterium."

Agrobacterium tumefaciens is a soil bacterium that naturally contains a specific plasmid known as the Ti (tumor-inducing) plasmid. This Ti plasmid carries genes responsible for causing crown gall tumors in plants by transferring a segment of its DNA (T-DNA, or transferred DNA) into the plant's genome.

Scientists exploit the natural ability of Agrobacterium to transfer genes into plant cells using the Ti plasmid for genetic engineering purposes. They can replace the tumor-inducing genes with the desired genes of interest, allowing Agrobacterium to transfer these genes into the plant's cells. This process enables the development of transgenic plants with the desired genetic traits.