Which organism is used to transfer T-DNA?
(a) Streplomyces hygroscopicus
(b) Agrobacterium tumefaciens
(c) Salmonella typhi
(d) Escherichia coli
(b) Ti plasmid (tumour inducing) from the soil bacterium Agrobacterium tumefaciens is effectively used as vector for gene transfer to plant cclls. The part of Ti plasmid transferred into plant cell DNA, is called the T-DNA. Th;s T-DNA with desired DNA spliced into it, is inserted into the chromosome of the host plant where it produces copies of itself, by migrating from one chromosomal position to another at random.