Which one of the following bacteria is commonly used for gene transfer in plants?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Agrobacterium tumefaciens
This bacterium is a pathogen of many dicot plants. It delivers a piece of DNA called the T-DNA into the plant cell and turns the normal cell into a tumour cell. Scientists use it as a vector after removing its tumour-causing genes, and put the gene they want in its place.
(1) E. coli — Incorrect. It is the usual host for cloning genes and for making proteins such as insulin. It is not used to carry genes into plants.
(2) Agrobacterium tumefaciens — Correct. It transfers its T-DNA into plant cells.
(3) Trichoderma polysporum — Incorrect. This is a fungus that makes cyclosporin A, a drug used to stop the rejection of transplanted organs.
(4) Salmonella typhimurium — Incorrect. A plasmid of this bacterium was used in the first recombinant DNA. It is not used to transfer genes into plants.
Note: NCERT prints the name as Agrobacterium tumifaciens. The correct spelling is Agrobacterium tumefaciens.
NCERT Extract:
Cloning Vectors – …
