Q.The bacteria, which possess Ti plasmid is :

The Ti plasmid, used as a natural gene-transfer vector in plant genetic engineering, is carried by the soil bacterium Agrobacterium tumefaciens.

Working

Agrobacterium tumefaciens is a Gram-negative soil bacterium that naturally infects wounded dicot plants and causes crown gall disease. It does this by means of a large Ti (tumour-inducing) plasmid: a segment of this plasmid, the T-DNA, is transferred from the bacterium into the plant cell and gets stably integrated into the plant's nuclear genome, where it directs the plant cell to produce opines (which the bacterium uses as nutrients) and to proliferate abnormally (the gall/tumour). Because the T-DNA transfer machinery will carry essentially any DNA placed between its border sequences into a plant chromosome, molecular biologists have engineered 'disarmed' Ti plasmids (with the tumour-causing genes removed but the transfer machinery intact) into one of the most widely used vectors for …