GATE 2021 BT – Question 45

Plant, Animal and Microbial Biotechnology · Plants: Hairy root culture, artificial seeds, somaclonal variation, protoplast fusion, transgenic plants, marker genes, plastid transformation · 2 marks · Multiple select

Which statements about Agrobacterium tumefaciens are correct?

It contains tumor-inducing plasmid
It causes crown gall in dicotyledonous plants
It is a Gram-positive soil bacterium
It is used to generate transgenic plants

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Show answer and explanation

Correct answer: (A) It contains tumor-inducing plasmid; (B) It causes crown gall in dicotyledonous plants; (D) It is used to generate transgenic plants

Explanation

Check each statement about *Agrobacterium tumefaciens*.

**A. Contains a tumour-inducing (Ti) plasmid.** True. The Ti plasmid carries the T-DNA and the *vir* genes. ✓
**B. Causes crown gall in dicotyledonous plants.** True. The T-DNA is transferred to the plant and its genes cause the tumour (crown gall) at wound sites. ✓
**C. A Gram-positive soil bacterium.** False. It is **Gram-negative**.
**D. Used to generate transgenic plants.** True. The T-DNA can be replaced with a gene of interest. ✓

Answer **A, B and D**.