Transgenic Plants and Gene Transfer

Transgenic Plants

• Transgenic plants are created by transferring or modifying genes from another organism to acquire desirable characters in the host plant.
• The goal of transgenic plants is to improve plant varieties by transferring a transgene into the plant genome.

Production of Transgenic Plants

• The steps involved in producing transgenic plants are:
  • Isolating the gene of interest
  • Adding a promoter or DNA segment to initiate or enhance gene expression
  • Adding a selection marker
  • Introducing the gene construct into a plant cell
  • Selecting transformed cells or tissue
  • Micropropagation to generate multiple plant clones

Insect Resistance

• Insect resistance in transgenic plants can be achieved through the use of genes from Bacillus thuringiensis (Bt).
• The Bt gene is also known as the Cry gene, which codes for the crystal (Cry) protein, a δ-endotoxin.
• The Cry protein works by binding to and creating pores in the intestinal lining of insects, ultimately killing them.

Mechanism of Cry Protein Toxicity

• Inside an insect's gut, the crystal breaks apart and releases the toxin.
• The toxin then binds to and creates pores in the intestinal lining, causing the insect's death.

Applications of Bt Gene

• The Bt gene provides resistance against several types of insects and nematodes, including:
  • Lepidoptera
  • Coleoptera
  • Hymenoptera
  • Diptera
  • Nematodes
• The Bt gene is used in the production of insect-resistant crops and biological insecticides.