Question

Some plant and animal pathogens serve as one of the tools of recombinant DNA (rDNA) technology.

1. Name one animal and one plant pathogen and discuss the pathogenic nature of both. State how they serve as a tool in rDNA technology.
2. What are the enzymes needed for rDNA technology?
3. A farmer owns a cotton farm land which is getting infested with coleopteran pests. He is not willing to use the microbes to protect his farm.
   1. Name an alternate method to introduce the gene of interest the pathogen would have otherwise delivered and discuss how the alternate method would deliver the gene.
   2. State how this gene would control the pest.

Answer 1

A. Animal pathogen: Retrovirus

• Pathogenic nature: Retroviruses can transform normal animal cells into cancerous cells.
• Use in rDNA technology: Disarmed retroviruses are used as cloning/gene transfer vectors to deliver desirable genes into animal cells.

Plant pathogen: Agrobacterium tumefaciens

• Pathogenic nature: It causes crown gall disease. It transfers its T-DNA (from Ti plasmid) into plant cells and converts normal plant cells into tumorous cells.
• Use in rDNA technology: Disarmed Ti plasmid is used as a cloning vector to deliver desirable genes into plant cells.

B. The enzymes needed for rDNA technology are restriction endonuclease (restriction enzyme) and DNA ligase.

C.

1. Biolistics/Gene gun method: Plant cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA carrying the gene of interest.
2. The cry gene produces Bt toxin. Inside the pest, the toxin gets activated in the alkaline gut and causes the gut epithelial lining to disintegrate, leading to death of the pest.

1.