Application of biotechnology in textile industry part 1 bt cotton feb 3, 2006


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Application of biotechnology in textile industry part 1 bt cotton feb 3, 2006

  1. 1. Application of biotechnology in textile industry Part 1 Harvesting of Bt cotton Prof. R.B.Chavan Department of textile technology Indian Institute of Technology Hauz-khas, New Delhi 10016 E.Mail rbchavan@hotmail.comIntroductionBiotechnology is defined as industrial exploitation of biological systems or processes.It includes any technique that uses living organisms or part of it to make or modifyproducts, to improve plants or animals or to develop microorganisms for specific uses.Individual characteristics of living organisms, such as the colour of petals, are determinedby their genes. These characteristics, or traits, are inherited from generation to generation.Genetic modification involves copying the genes which govern a particular characteristic.from one organism, and transferring them to another. With conventional breeding, traitscan only be transferred between plants or animals of the same or closely related species.Genetic modification enables traits to be transferred between different species. The rapiddevelopments in the field of genetic engineering have given a new impetus tobiotechnology. With an improved understanding of how different genes are responsiblefor the various characteristics and properties of a living organism, techniques have beendeveloped for isolating these active components (in particular, the DNA which carries thegenetic code) and manipulating them outside of the cell. The next step has been tointroduce fragments of DNA obtained from one organism into another, therebytransferring some of the properties and capabilities of the first to the second.Discoveries in Biotechnology allow for certain key crops to have their own protectionagainst insects and disease. These crops can, therefore, be grown using less pesticides.India loses tremendous amounts of crops to pests and diseases. For example, India is the3rd largest producer of cotton in the world. While cotton occupies only 5% of thecultivated area, it accounts for almost half the pesticides sold in India. This is due to thedevastating pest the cotton bollworm. One of the plants that are undergoing evaluation inIndia is Bt cotton (Bacillus thurigiensis) that offers protection against this pathogen and
  2. 2. will drastically reduce the use of pesticides. In the future, some applications ofBiotechnology will be used to make materials such as fibers for clothes from “renewable”resources like corn. Other applications may help reduce our dependence on oil andnatural gas and could reduce water and energy use by as much as 50 percent.Some of the technologies relevant to textile industry based on biotechnologicalapplications are 1. Harvesting of Bt cotton 2. Natural polyester in the form of poly hydroxy butyrate to grow within central hollow channel of the cotton fibre. 3. Biodegradable polyester from corn 4. Biosynthesis of indigo and other colours 5. Monochlonal anti bodies for the identification of branded products such as denim. 6. DNA probes 7. Biosensors 8. Chemical processing of textiles 9. Aftercare of garments 10. Effluent treatment. etc.In the present article the harvesting of Bt cotton in India is discussedBt CottonCotton crop is easily attacked by various types of pests causing extensive damage. Someof the pests which cause major damge to cotton crop areCotton bollworm, Tobacco budworm, loopers, fall armyworm, beet armyworm etc. Theseworms are shown pictorially
  3. 3. Cotton bollworm Tobacco budworm Loopers Fall armyworm Beet armywormBollworm damage of non-Bt cotton
  4. 4. Intensive use of pesticides is essential to protect cotton crop. Almost 50% of pesticideconsumption is accounted for cotton. Over the past 40 years; many pests have developedresistance to pesticides. We have a year. TheSo far, the only successful approach to engineering crops for insect tolerance has been theaddition of Bt toxin (Bacillus thurigiensis), a family of toxins originally derived fromsoil bacteria. The Bt toxin contained by the Bt crops is no different from other chemicalpesticides, but causes much less damage to the environment. These toxins are effectiveagainst a variety of economically important crop pests but pose no hazard to non-targetorganisms like mammals and fish. Three Bt crops are now commercially available:cotton, corn, and potato.The Bt gene was isolated and transferred from a bacterium bacillus thurigiensis toAmerican cotton. The American cotton was subsequently crossed with Indian cotton tointroduce the gene into native varieties.The Bt cotton variety contains a foreign gene obtained from bacillus thuringiensis. Thisbacterial gene, introduced genetically into the cotton seeds, protects the plants frombollworms, a major pest of cotton. The worm feeding on the leaves of a BT cotton plantbecomes lethargic and sleepy, thereby causing less damage to the plant.ThusBt cotton has been genetically modified by the insertion of one or more genes from acommon soil bacterium, Bacillus thuringiensisIn 1996, Bollgard cotton (a Trademark of Monsanto) was the first Bt cotton to bemarketed in the United States. The original Bollgard cotton produces a toxin calledwhich has excellent activity on tobacco budworm and pink bollworm. These two insectsare extremely important caterpillar pests of cotton, and both are difficult and expensive tocontrol with traditional insecticides. Bollgard toxin also has moderate activity onbollworm and to a lesser extent on loopers, fall armyworms and beet armyworms.Bollgard II was introduced in 2003, representing the next generation of Bt cottons.Bollgard II contains a second gene from the Bt bacteria which encodes the production ofCry 2Ab. WideStrike (a Trademark of DowAgrosciences) was registered for use in2004. Like Bollgard II, WideStrike cotton expresses two Bt toxins (Cry1Ac and Cry1F).Both Bollgard II and WideStrike have better activity on a wider range of caterpillar pests
  5. 5. than the original Bollgard technology. Bt cottons from other companies are currentlyunder development but have not been commercially introduced.How Bt cotton affects insect pest managementBt cotton eliminates the need to treat for infestations of tobacco budworm or pinkbollworms. Prior to bloom, the need to treat for bollworm is greatly reduced. However,the level of bollworm control provided by Bollgard cotton may not be sufficient oncecotton has begun to bloom. Bollgard may also suppress the development of damagingpopulations of other caterpillar pest, but insecticidal sprays on Bollgard cotton for controlof bollworm, loopers, and beet and fall armyworm are sometimes needed. Supplementalinsecticides sprays for bollworm, loopers and armyworms will be less likely on BollgardII and WideStrike cottons.Resistance and resistance managementIt seems likely that some cotton pests could develop resistance to Bt crops if they areextensively used. Insects such as the tobacco budworm are well known for their ability todevelop resistance to many insecticides, including Bt toxins. Because of this, there arerestrictions associated with the use of Bt cotton that are intended to prevent or delay thedevelopment of resistance. The primary resistance management strategy is themandatory planting of a non-Bt cotton Refuge. The plantation of non-Bt cotton close toor adjacent to Bt cotton fields will provide a source of susceptible moths for mating withresistant moths that survive in Bt cotton The refuge serves as a source of susceptibleinsects that would potentially breed with any resistant insects generated in Bt cottonfields. The offspring of this mating would be susceptible to Bt toxinsA second resistance management tactic would be the introduction of Bt crops thatproduce two or more relatively dissimilar toxins. Presumably, it is less likely that anyone insect will be simultaneously resistant to more than one toxin. It is expected thatBollgard II, WideStrike and Bt cottons from other companies will eventually replace theoriginal Bollgard technology in 5-6 years.Is Bt cotton safe?Bt toxins are highly specific. The toxins produced by Bt cotton and corn are toxic to aselect number of arthropod species. Because cotton is primarily a fiber crop, the
  6. 6. contamination of food with toxins from cotton is highly unlikely. However, extensivetesting indicates a very low public health risk from the use, including ingestion, of foodproducts that utilize currently-available Bt crops.Negative impacts on non-target arthropods are potential concerns resulting from the useof Bt crops. Concerns were raised because corn pollen, containing Bt toxins, could beblown onto plants which serve as hosts to monarchs, swallowtails, and other butterflies.This is not a minor issue with cotton because, unlike corn, it is not wind pollinated. Itshould also be considered that Bt crops often reduce the use of broad spectruminsecticides, thereby reducing the impacts of these application on the environment andnon-target organisms.