Question

State how has Agrobacterium tumifaciens been made a useful cloning vector to transfer DNA to plant cells.

Answer 1

Agrobacterium tumefaciens is a plant pathogen and most effective as plant genetic engineer. It causes the formation of crown gall in plants. The tumor-inducing plasmid Ti can be used as a useful cloning vector in plants. It can be modified with new DNA and the plasmid introduces a piece of DNA which transforms normal plant cells into tumor cells. The Ti plasmid contains genes for the synthesis of auxin and cytokinin hormone and thus its introduction in a plant helps it to produce its own nutrient machinery.