Bt cotton

its about the bt cotton production and its action

1. Aneesha .A II nd MSc.Botany University college

2. Transgenic plant Plant that have been genetically engineered a breeding approach that uses recombinant DNA techniques to create plant with new characteristics

3. Bt cotton Genetically modified cotton crop to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis . Mahyco (Maharashtra Hybrid Seeds Company ) in collaboration with US company Monsanto has introduced Bt cotton in India in 2002

4. Why we need Bt cotton About 162 species of insects occur in cotton at various stages of growth of which 15 are key pests ( Kannan et al ., 2004). About 9400 M tonnes of insecticides worth Rs 747 crores were used only for bollworm control in 2001 ( Kranthi , 2012 ). Before the introduction of Bt cotton, insecticide quantity applied on cotton was the highest, relative to other cultivated crops .

5. Cotton bolls are highly vulnerable to hidden insects such as the American bollworm, Pink bollworm and Spotted bollworm .

6. What is Bt? Bt stands for Bacillus thuringiensis discovered by Ishiwatari in 1901. It is a rod shaped, aerobic, spore forming, Grampositive , soil-dwelling bacterium Bacillus thuringiensis (or Bt ), commonly used as a biological alternative to a pesticide

7. Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ-endotoxins (called crystal proteins or Cry proteins), which are encoded by cry genes

8. Bt strain active against various types of insects

9. Classification of cry genes and their pathogenicity Cry gene Toxic to the insect order Cry1A(a), Cry1A(b), Cry1A(c) Lepidoptera Cry1B, Cry1C, Cry1D Lepidoptera Cry II Lepidoptera, Diptera CryIII Coleoptera CryIV Diptera CryV Lepidoptera, Coleoptera

10. Structure of Cry Protein

11. Mode of action

12. Larvae feed on Bt plants Crystal enter the digestive tract, where they make their way to the organism's gut. Protoxin get activated by the combination of alkaline pH(7.5-8)& specific digestive protease Covert protoxin into active toxin The active toxin traverses the peritrophic membrane

13. To bind cadherin receptors present on the brush border membrane The cadherins process the toxins to form homo-oligomers and bind to specific receptors Create an ion channel osmotic lysis of the cells Cellular metabolism ceases Few hours – it become hydrated 2-5 days - insect eventually die

14. How Bt cotton is developed? For development of any transgenic crop, there are five important steps: Identification of effective gene or genes. Gene transfer technology. Regeneration ability Gene expression of the product at desired level. Proper integration of gene .

15. Toxin Gene Isolation Whether the toxin genes are located on a plasmid or on the chromosomal DNA? O n a plasmid

16. medium and large plasmid fractions are each partially digested with Sau3AI and then ligated into the BamHI site of plasmid pBR322 . clones were transformed into Escherichia coli

17. Colonies are transferred to a nitrocellulase membrane Transformed colonies are lysed with organic solvents Blocked by BSA Adding antibody against protoxin Treated with Sa A protein Autoradiography

18. Agrobacterium mediated gene transfer

19. Particle Gun method

20. Safeguard measurement Refugia U se of multiple toxins High-Dose Strategy

21. Advantages of Bt cotton in India High insect specificity Nontoxic to non-target species Biodegradable Reduction of usage of insecticides Yield increases

22. Disadvantages of Bt cotton Small and marginal farmers of India can not afford the high cost of Bt cotton seeds, Rs.1600 for 450 g of seeds . Adverse effect on insecticide manufacturing companies due to reduced use of pesticides significantly by Bt cotton Ineffective against sucking pests like jassids , aphids, whitefly etc.

23. Adverse effect on the employment of those persons engaged in pesticide industries. Promotes malpractices

24. Conclusion To get the full benefit of Bt cotton, the ideal approach is integrated pest management (IPM) where Bt -cotton is relied upon to control bollworms while it is necessary to be watchful and take appropriate control measures against those pests not controlled by Bt -cotton

25. Reference Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten; Molecular biotechnology : principles and applications of recombinant DNA 4 th ed;2010; Library of Congress Cataloging-in-Publication Data K. R. Kranthi ; bt cotton q&a questions and answers;2012; indian society for cotton improvement, ( isci ) Bhagirath choudharykadambini gaur; bt cotton in india : a country profile;2010; the international service for the acquisition of agri -biotech applications ( isaaa D.D. Hardee, j.W. Van duyn, m.B . Layton, and r.D. Bagwell; bt cotton & management of the tobacco budworm-bollworm complex;2001; united states department of agriculture J. L. Karihaloo&p . A. Kumar; bt cotton in india (second edition);2009; asia -pacific consortium on agricultural biotechnology ( apcoab ) Dr cd mayee.Et al; transgenic bt cotton; central institute for cotton research Nagpur

26. Thank you