Bt in "Bt Cotton" stands for Bacillus thuringiensis. This is naturally occurring soil bacterium. Somatic hybridization involves fusion of protoplast of two cells. "Flavr savr" is genetically engineered tomatoes which express delayed softening by insertion of an additional copy of PG endociding gene. $\mathrm{PG}$ is poly galacturonase enzyme which is responsible for the breakdown of cell wall pectin. Transgenic Brassica napus seeds are being used to produce the anticoagulant hirudin.