Whats the molecular mechanism undergoing during Agrobacterium mediated transformation?

Answer 1

To put it in simpler terms, Agrobacterium have evolved a mechanism to cause cancer like galls in plants, by inseting genes into the host chromosome that cause cell division. These genes are carried on a relatively small circular DNA called the T1 plasmid. Researchers have manipulated this system for their own use, by replacing the genes in the transforming region of the plasmid with their own genes of interest. The agro, carrying these new genes will still infect and insert this DNA into the host plant.

Answer 2

The molecular basis of genetic transformation of plant cells by Agrobacterium is transfer from the bacterium and integration into the plant nuclear genome of a region of a large tumor-inducing (Ti) or rhizogenic (Ri) plasmid resident in Agrobacterium. Ti plasmids are on the order of 200 to 800 kbp in size (81, 100, 111, 114, 145, 166, 175, 177, 245, 250, 251, 261, 311, 332, 342, 363). The transferred DNA (T-DNA) is referred to as the T-region when located on the Ti or Ri plasmid. T-regions on native Ti and Ri plasmids are approximately 10 to 30 kbp in size (17, 34, 197, 311, 378). Thus, T-regions generally represent less than 10% of the Ti plasmid. Some Ti plasmids contain one T-region, whereas others contain multiple T-regions (17, 311). The processing of the T-DNA from the Ti plasmid and its subsequent export from the bacterium to the plant cell result in large part from the activity of virulence (vir) genes carried by the Ti plasmid (106, 147, 148, 174, 208, 303).