Transgenic cotton, such as Bt cotton, is genetically modified to produce insecticidal proteins that target harmful pest insects. Bt cotton was developed using genes from Bacillus thuringiensis bacteria, which produce Cry proteins that are toxic to insect pests but safe for humans. The technology involves identifying effective insecticidal genes, transferring the genes into cotton plants, regenerating transgenic cotton plants, and field testing before commercial approval. Bt cotton provides benefits like higher yields and reduced need for pesticides compared to conventional cotton.

1. TRANSGENIC
COTTON
PRESENTED BY;
TAHREEM ARIF
2018-AG-99

2. INTRODUCTION
• Cotton is the most important textile and cash crop.
• Widely cultivated in more than 70 countries, including
Pakistan, United States, China, and India.
• Transgenic techniques have become a powerful tool to improve
cotton.
• Transgenic cotton is among the first commercially genetically
modified crops.

3. WHAT IS BT COTTON?
•Bt Cotton is also a transgenic cotton.
•Genetically modified variety of cotton that
produces an insecticide.
•Marketed by Monsanto, USA.

4. CONTINUE…
•Bacillus thuringiensis discovered by
Ishiwatari in 1901.
•Bacterium produces insecticidal crystal
protein (ICP) also known as Cry protein
•They are a class of endotoxin – δ
endotoxins

6. TIMELINE…
• In 1901, Shigetane Ishiwatari first isolated the bacterium Bacillus
thuringiensis as the cause of the sotto disease.
• In 1915, Berliner reported the existance of a crystal within Bt, but the
activity of this crystal was not discovered until much later.
• In 1956, Researchers Hannay, Fitz-James and Angus found that the
main insecticidal activity against lepidoteran (moth) insects was due
to the parasporal crystal.
• In 1958, In the US, Bt was used commercially.
• In 1961, Bt was registerd as a pesticide to the EPA.
• In 1996, Bt cotton was introduced into US agriculture.

8. OBJECTIVES
•To understand the general mode of action of
Cry toxin
•To understand the technology behind Bt
cotton production.
•To comprehend the current scenario of Bt
cotton in Pakistan.

9. HOW BT WORKS?
•Ingestion
•Solublization & proteolytic activation
•Binding to target site
•Formation of toxic lesion

10. MODE OF ACTION OF CRY TOXIN

11. TECHNOLOGY OF PRODUCTION
• Main steps for developing transgenic crops :
1. Identification of effective gene(s).
2. Gene transfer
3. Regeneration from protoplast/callus/tissue
4. Gene expression to the desired level
5. Back cross to produce varieties
6. Field test
7. Approval for commercialization

12. METHODS OF GENE TRANSFER
•Agrobacterium mediated gene
transfer
•Bombardment of cells with particle
coated with gene of interest

13. TRANSFORMATION
WITH
AGROBACTERIUM
• Agrobacterium contains a
circle of DNA (Ti plasmid)
that carries the desired
genes.
• Co-cultivation of the
Agrobacterium with plant
pieces transfers the DNA

14. AGROBACTERIUM MEDIATED GENE
TRANSFER

15. ‘PARTICLE GUN’
• DNA coated on pellets is
forced down the barrel of a
‘Particle Gun’ by an
explosive charge
• The particles are forced
through the cell wall where
the DNA is released

16. ADVANTAGES
•Yield superiority
•More profit
•Lesser need of pesticide
•Better quality
•Suitability for early sowing

17. DISADVANTAGES
•Higher cost of seeds
•Higher fertilizer and irrigation cost
•Higher harvest cost

18. REFERENCE
• Aronson, A. (2002). Sporulation and δ-endotoxin synthesis by Bacillus
thuringiensis. Cellular and Molecular Life Sciences CMLS, 59(3),417-425.
• Bravo A., Gill S. S., & Soberon M. (2007). Mode of action of Bacillus
thuringiensis Cry and Cyt toxins and their potential for insect control.
Toxicon, 49(4),423-435.
• Dulmage, H.T. (1981) Insecticidal activity of isolates of Bacillus
thuringiensis and their potential for pest control. In Microbial Control of
Pests and Plant Diseases 1970-80 (Burgess, H.D., ed.). New York, NY:
Academic Press, pp. 193-222.
• English, L. and Slatin, S.L. (1992) Mode of action of deltaendotoxin from
Bacillus thuringiensis: a comparison with otherbacterial toxins. Insect
Biochem. Molec. Biol. 22, 1-7.

19. CONTINUE…
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