_________a crown gall bacterium, is called an natural genetic engineer' of plants.

Options

A. 1) Escherichia coli
B. 2) Streptomyces albus
C. 3) Agrobacterium tumefaciens
D. 4) Azotobacter

Answer

C

Explanation

A soil-inhaiting plant bacterium Agrobacterium tumefaciens is a pathogen of several dicot plants. It is able to transfer a piece of DNA known as 'T-DNA' into the plant cells. The T-DNA caues tumours, the tumours are called crown galls. Tumour formation is induced by Ti plasmid (Ti for tumour inducing). As gene transfer occurs without human effort, the bacterium is called natural genetic engineer of plants. Similarly retroviruses in animals including humans are able to change normal cells into cancerous cells.