Final answer:
The Ti plasmid is naturally found in Agrobacterium, particularly in Agrobacterium tumefaciens. This plasmid is utilized in biotechnology to create transgenic plants after modifying and removing tumor-causing genes.
Step-by-step explanation:
The Ti plasmid is naturally found in Agrobacterium, specifically in the species Agrobacterium tumefaciens. In nature, the disease-causing A. tumefaciens harbor these plasmids which have the ability to integrate into plant cells and cause tumor formation. However, researchers have been able to utilize the Ti plasmid by removing the tumor-inducing genes and inserting genes of interest. This method is employed to create transgenic plants where the inserted gene recombines with the plant cell's genome. While these plasmids are associated with Agrobacterium, they can also be propagated in E. coli for experimental purposes.