Question

Ti plasmid is used for making transgenic plants. It is obtained from

• A. $Rhizobiuminleguminousroot$
• B. $Agrobacterium$
• C. Yeast
• D. $Azotobacter$

Answer 1

The correct option is B $Agrobacterium$

Transgenic plants
Plants containing one or more genes from another species are called transgenic plants. They have been created by genetic engineering processes.

Ti plasmid
The Ti plasmid or tumour inducing plasmid (extrachromosomal DNA) is carried by $Agrobacteriumtumefaciens$. The T-DNA segment of the Ti plasmid integrates itself into the plant cell’s genome to induce tumour formation in plants. This property of the plasmid makes it an effective vector for transferring foreign genes into plant cells.

$Azotobacter$
$Azotobacter$ is a free living bacteria that convert atmospheric nitrogen to ammonia, which is taken up and utilised by the plants.

$Rhizobium$
$Rhizobium$ is a bacterium that forms a symbiotic relationship with the roots of leguminous plants. It helps in fixing atmospheric nitrogen which is used by the plant for its growth and development.

Yeast
Yeasts are single celled organisms present in the kingdom Mycota. Yeast artificial chromosomes are genetically engineered DNA obtained from Saccharomyces cerevisiae, that is used to clone DNA sequences. Up to one million base pairs can be inserted into these chromosomes.

Final answer:
b. $Agrobacterium$