Question

Agrobacterium tumefaciens uses the Ti plasmid to create galls to provide a nutrient rich environment for this species. Discuss how this process is used by companies like Bayer to create genetically modified corn plants that can produce a toxin that kills corn borer worms..

Answer 1

Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton.The choice of genes depends upon the crop and the targeted pest, as most Bt toxins are insect-group specific. The toxin is coded by a genecryIAc named cry. There are a number of them, for example, the proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms,that of cryIAb controls corn borer.

Corn varieties resistant to glyphosate herbicides were first commercialized in 1996 by Monsanto, and are known as "Roundup Ready Corn"

Resistant strains of the European corn borer have developed in areas with defective or absent refuge management.

In November 2009, Monsanto scientists found the pink bollworm had become resistant to first-generation Bt cotton in parts of Gujarat, India – that generation expresses one Bt gene, Cry1Ac. This was the first instance of Bt resistance confirmed by Monsanto anywhere in the world.