Tiêu đề Biotechnology-and-Its-Applications-3.pdf ✅

Biotechnology and Its Applications 2. ⚪ organic agriculture ⚪ genetically engineered crop-based agriculture y Green Revolution took place in the late sixties. Norman Borlaug is known as the Father of Green Revolution. He tried to increase the agricultural productivity in the world. y In India M.S. Swaminathan initiated Green Revolution and encouraged modern methods and technology for agriculture. ⚪ It aimed at increasing the yield of the crops. ⚪ This was done by providing improved variety of seeds to the farmers (high yielding variety) improving irrigation facilities providing good use of agrochemicals. y For the farmers of developing country it is difficult to afford agrochemicals for their farming practices. y The normal breeding technique was not giving high yield of crops and thus it was necessary to think about other alternative ways to increase the yield of crops and to fight against the pests. y Are there ways that can be used to increase the yield of the crops but also to reduce the dependency on fertilizers, pesticides and insecticides? y The answer to the above question was found in the field of biotechnology and it was applied to different plants, animals and microbes. y The plants, animals and microbes that are genetically modified by biotechnology are known as Genetically Modified Organisms. y Genetically modified plants and crops have been useful. They are being used by the farmers. The following are the advantages of genetically modified plants: Definition Genetically Modified Organisms (GMO): Plants microbes, fungi and animals whose genes have been altered by manipulation are called GMO. Gray Matter Alert!!! Golden Rice: Ingo Potrykus and Peter Beyer genetically produced golden rice. It is a rice variety which has a high quantity of beta carotene, which is a provitamin A. Beta carotene converts into vitamin A when metabolised by humans. The colour of rice grain is yellow. Previous Year’s Question Golden rice is a transgenic crop of the future, with the following improved trait (1) insect resistance (2) high lysine (essential amino acid) content (3) high protein content (4) high vitamin – A content
3. Biotechnology and Its Applications Production of pest resistance plants y Bacillus thuringiensis has a gene that produces a toxin which has pesticide properties. This gene can be isolated from the bacteria and integrated with different plants to provide them resistance against certain pests. y The cryI gene of B. thuringiensis produces protein, that is responsible for the insecticidal activities of the bacteria. y The protein kills lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). y The bacteria Bacillus thuringiensis produces protein crystals which contain the insecticidal proteins. y The crystal does not kill the bacteria as the Bt toxin protein exists as inactive protoxins in the Gray Matter Alert!!! Flavr Savr: It is a transgenic tomato. It has been made resistant to rotting and thus has high shelf value.
Biotechnology and Its Applications 4. bacteria and alkaline pH is required to activate the crystals. y Once inside the body of the insect, the alkaline pH of the gut activates the protoxin and the crystal becomes soluble in the insect’s gut. y The toxin binds to the epithelial lining of the gut creates pores and causes the cell to swell and then lyses. This kills the insect. y The Cry proteins into four main groups, Cry-I, Cry-II, Cry-III and Cry-IV, on the basis of their insecticidal activities. The choice of genes depends upon the crop and the targeted pest. The proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms, that of cryIAb controls corn borer. There are many insect species that are not sensitive to Cry proteins; this could be due to a high affinity of midgut proteases of these species to the Cry proteins. In such insect species, the Cry proteins seem to be cleaved into several fragments. Pest resistance in Plants-RNAi Mediated Interference (RNA) y Roots of Tobacco plant is infected by a nematode Meloidegyne incognitia. It affects the yields of the leaves. Rack Your Brain Why are the proteins coded by cryIAc, cryIAb and cryIIAb are slightly different in their control?