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Bt Cotton Development Stages

Bt cotton is a genetically modified organism (GMO) or genetically modified pest resistant plant cotton variety, which produces an insecticide to combat bollworm.

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Bt Cotton Development Stages

  1. 1. Source:- K. R. Kranthi, Ph.D, FNAAS, Director, Central Institute for Cotton Research, Nagpur Dr. Pavan J Kundur M.Sc., Ph.D., Assistant Professor Department of Biotechnology P C Jabin Science College Hubballi, Karnataka, India Bt Cotton
  2. 2. What is Bt-cotton?  Bt cotton is genetically modified cotton crop that expresses an insecticidal protein whose gene has been derived from a soil bacterium called Bacillus thuringiensis, commonly referred as Bt.  Many subspecies of B.thuringiensis are found in soils and are in general known to be toxic to various genera of insects but safe to other living organisms.  Bt was first discovered by a Japanese scientist Ishiwata in the year 1901.  Bt has been used as an insecticide for control of stored grain pests since 1938 in France and from 1961 as a registered pesticide in the USA  later in many other countries including India as sprays in cotton IPM programs to control insects. Marketed by Monsanto, USA
  3. 3. Bt toxins thus have several decades of proven selective toxicity to insect pests and with established safety record to non-target animals. Currently there are 67 recognized subspecies of B. thuringiensis most of which produce spores and insecticidal proteins. The Bt gene cry1Ac was used to develop the first Bt-cotton variety. The gene was transferred into the genome of cotton explants (tissue pieces) using a bacterium called Agrobacterium tumefasciens. The transformed cells were developed into a full GM plant now called Bt- cotton. In general, Cry1Ac toxins are highly specific to insects at species level, and are not known to cause any harm to non-target species such as fish, birds, farm animals and human beings.
  4. 4.  Currently, Cry1Ac, Cry2Ab and Cry1C have been approved for commercial cultivation in India.  Bt cotton hybrids available in India are derived from technologies developed by Monsanto  Dow Agro sciences are conducting field trials with Cry1Ac + Cry1F and Bayer is introducing Cry1Ab + Cry2Ae.  There were 1128 Bt-cotton hybrids in 2012, developed by 40 seed companies, available in the Indian markets.
  5. 5. Why do we need Bt-cotton? a) Cotton is a long duration crop and is attacked by large number of insect pests throughout its growth and development. b) The three bollworms, American bollworm Helicoverpa armigera, Pink bollworm Pectinophora gossypiella and the Spotted bollworms, Earias vittella and Earias insulana are major pests and cause serious threat to cotton production resulting in significant yield losses. c) About 9400 M tonnes of insecticides worth Rs 747 crores were used only for bollworm control 2011 d) insecticide quantity applied on cotton was the highest
  6. 6. e) Bollworms are hidden feeders and generally do not come into direct contact with insecticide sprays. f) 50.0% of all insecticides in India were being unsuccessfully used for cotton pest control, until the year 2001, before Bt cotton was introduced. G) Resistant sources are unavailable in the germplasm and resistance breeding has been unsuccessful.
  7. 7. Do we need other Bt-crops? Your Answer
  8. 8. How does Bt-cotton kill insects? 1. Ingestion 2. Solublization & proteolytic activation 3. Binding to target site 4. Formation of toxic lesions
  9. 9. Structure of Cry protein Cry6Aa Source :- Wikipedia Domain I •7 α-helix •Helps in membrane insertion Domain II •β-prism of 3 antiparallel β-sheets •Helps in receptor recognition Domain III • β-sandwich of antiparallel β - sheeets
  10. 10. Dr. Juan Luis Jurat-Fuentes Department of Entomology and Plant Pathology The University of Tennessee 2431 Joe Johnson Drive 205 Ellington Plant Sciences Building Knoxville, TN, 37996 Tel: (865) 974-5931 jurat@utk.edu How Cry protein works?
  11. 11. ingestion of the Cry protein by a susceptible insect, solubilization, and procesing from a protoxin to an activated toxin core in the insect digestive fluid. The toxin core travels across the peritrophic matrix and binds to specific receptors called cadherins on the brush border membrane of the gut cells. Toxin binding to cadherin proteins results in activation of an oncotic cell death pathway and/or formation of toxin oligomers that bind to GPI- anchored proteins and concentrate on regions of the cell membrane called lipid rafts. * Glycosyl phosphate dylinositol Accumulation of toxin oligomers results in toxin insertion in the membrane, pore formation, osmotic cell shock, and ultimately insect death.
  12. 12. Advantages of Bt-cotton • Yield superiority • More profit • Lesser need of pesticide • Better quality • Suitability for early sowing Disadvantages • Higher cost of seeds • Higher fertilizer and irrigation cost • Higher harvest cost
  13. 13. Bt cotton in India • India is the largest cotton producer and consumer country after China. • In 2002 Bt cotton was introduced in India. • India has the largest hectarage of cotton and accounts for approximately one third of the total cotton are planted in the world. • For 11th year Bt cotton was planted in India in10.8 mil hectares . • Decline in insecticide use was from US$160 million in 2004 to US$25 million in 2010 –an 85% decrease • Cotton yield increased from 308kg/ha in 2001-02 to 500kg/ha in 2011-12.
  14. 14. How many Bt-hybrids are available in India? The Bt-cotton technology was first approved in 2002 by the GEAC for commercial cultivation in central and south Indian cotton–growing zones in India in the form of three hybrids (MECH-12, MECH-162, and MECH-184) By the end of July 2008, the total number of Bt-hybrids increased to 283. By August 2009 the number increased to 564 Bt-hybrids and one Bt-variety. By August 2010 the total number of Bt-hybrids increased to 809 By May 2012 there were 1128 Bt cotton hybrids available in the market.
  15. 15. Govt keeps Bt cotton price unchanged at Rs 730 per packet for 2020-21; scraps royalty fee to Bayer Bayer, which in June 2018 completed the USD 63-billion deal to acquire Monsanto, has expressed disappointment over doing away with trait value or royalty altogether. According to a government notification, the maximum sale price for Bollgard-II (BG-II) cotton seed for 2020-21 has been fixed at Rs 730 per packet of 450 gm. The seed value is Rs 730 and trait value zero. Read more at: https://economictimes.indiatimes.com/industry/indl-goods/svs/chem-/- fertilisers/govt-keeps-bt-cotton-price-unchanged-at-rs-730-per-packet-for- 2020-21-scraps-royalty-fee-to- bayer/articleshow/74827836.cms?utm_source=contentofinterest&utm_medium =text&utm_campaign=cppst
  16. 16. 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 other bacterial toxins. Insect Biochem. Molec. Biol. 22, 1-7. • Perlak, F.J., Deaton, R.W., Armstrong, T.A., Fuchs, R.L., Sims, S.R., Greenplate, J.T. and Fischhoff, D.A. (1990) Insect resistant cotton plants. Bio/Technol. 8, 939-943
  17. 17. Thank You