Q.

Bacillus thuringiensis has a cry gene that codes for a toxic protein called Cry protein. Thermus aquaticus is found in hot water spring. It has thermostable DNA polymerase named Taq polymerase. Agrobacterium tumefaciens has a ti plasmid that is modified to use as cloning vector. The tumor inducing (Ti) plasmid of Agrobacterium tumifaciens has now been modified into a cloning vector which is no more pathogenic to the plants but is still able to use the mechanisms to deliver genes of our interest into a variety of plants.The construction of the first recombinant DNA emerged from the linking of a gene encoding antibiotic resistance with a native plasmid of Salmonella typhimurium.