Question

Why is Agrobacterium tumefaciens a good cloning vector? Explain.

Answer 1

Agrobacterium tumefaciens is a good cloning vector because it naturally transfers a piece of its DNA, called T-DNA, into the genome of dicotyledonous plants, causing tumour formation. Its large extrachromosomal plasmid, the Ti plasmid, contains the T-DNA region which integrates into the plant’s nuclear genome. In genetic engineering, the Ti plasmid is modified to remove its pathogenic genes, making it safe for use as a vector to insert foreign genes into plants. This ability to efficiently transfer and integrate foreign DNA into plant cells makes it an excellent tool for genetic transformation. Additionally, the T-DNA transfer is precisely controlled by bacterial genes (vir region), and the system is activated by phenolic compounds from injured plant cells, facilitating targeted gene transfer and stable transformation in plants.