What is the term used for the piece of DNA that Agrobacterium tumefaciens delivers into dicot plants?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → T-DNA
Agrobacterium tumefaciens is a pathogen of several dicot plants. It delivers a piece of its DNA, called T-DNA, into plant cells. The T-DNA turns normal plant cells into a tumour and makes these cells produce the chemicals the bacterium needs. Scientists have used this natural skill: the tumour-inducing (Ti) plasmid of this bacterium has been changed into a cloning vector that no longer causes disease but still delivers useful genes into plants.
NCERT Extract:
Cloning Vectors – “… For example, Agrobacterium tumifaciens, a pathogen of several dicot plants is able to deliver a piece of DNA known as ‘T-DNA’ to transform normal plant cells into a tumor and direct these tumor cells to produce the chemicals required by the pathogen.”
Cloning Vectors – “… The tumor inducing (Ti) plasmid of Agrobacterium tumifaciens has now been modified into a cloning vector which is no more pathogenic to the plants but is still able to use the mechanisms to deliver genes of our interest into a variety of plants.”