Question

Explain the use of Agrobacterium tumefaciens in gene cloning?

Answer 1

Hint: Agrobacterium is a soil bacterium known as rhizobium radiobacter. It is used extensively in the genetic engineering of plants. It is used to transfer a small segment of DNA into the genome of a plant.

Complete step by step answer: Agrobacterium tumefaciens is the plant pathogen and is the most effectively used genetically plant. It causes infection in the form of crown gall in plants. The tumor-inducing plasmid Ti can be used as a useful cloning vector in gene cloning in plants.
The Ti plasmid introduces a DNA piece which transforms the normal plant cells into tumor cells. The tumor cells also contain genes for the synthesis of auxin and the cytokinin hormones and thus its insertion in a plant helps in producing its own nutrient machinery.
Agrobacterium is the most commonly used method in gene cloning because of its relative high efficiency during transformation. Several components of the tumor inducing plasmid helps in effective transfer of genes of interest into the plant cells.
The T-DNA sequence makes the DNA segment to be transferred into the plant.
Virulence genes are required for transferring the T-DNA region to the plant.
The modified T-DNA region where the genes that cause crown gall formation are removed and replaced with the genes of interest.

Note: Bacteria of the genus Agrobacterium are used extensively. They are the unusual plant pathogens, though are a rare DNA transfer, it moves some of their genes into their host genome. This results in proliferation of host cells and the production of opines, nutrient sources to the pathogen.