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In nature, Agrobacterium tumefaciens mediated infection of plant cells leads to
P. crown gall disease in plants
Q. hairy root disease in plants
R. transfer of T-DNA into the plant chromosome
S. transfer of Ri-plasmid into the plant cell
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- S only
- P and R only
- Q and S only
- Q only
Correct Option: B
Agrobacterium tumefaciens is a gram-negative rod-shaped bacterium. It infects plants usually through an open wound. Once it enters its plant host, it injects a section of its DNA called the T-DNA which is derived from its Ti (tumor inducing) plasmid into its host. The T-DNA is then integrated into the plant’s genome, and has two effects on the plant host. The T-DNA first directs the plant cells to make auxins and cytokinins, which causes the cells to become irregularly shaped and form a visible tumour called a gall. The T-DNA then directs the plant cell to start making opines (usually nopaline or agropine) which A. tumefaciens use as an energy source.
