Question

A dicotyledonous plant forms crown gall when

• A. Agrobacterium tumefaciens comes in contact with the plant.
• B. Agrobacterium rhizogenes comes in contact with the plant.
• C. A specific part of DNA from the Ti plasmid gets integrated with the plant chromosome.
• D. A specific part of DNA from the Ri plasmid gets integrated with the plant chromosome.

Answer 1

The correct option is C A specific part of DNA from the Ti plasmid gets integrated with the plant chromosome.

A dicotyledonous plant forms crown gall when a specific part of DNA known as T DNA from the Ti plasmid gets integrated with the plant chromosome. The T DNA replicates and gets integrated into the plant’s genome, causing the production of tumours and associated changes in plant metabolism. It has length of 15 to 30kb. It contains genes that code for enzymes synthesizing opines and phytohormones which allows tumorous growth in plant.

So, the correct answer is option C.