2.BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE
Introduction
Overview of the three options for increasing food production.
Agro-chemical Based Agriculture
Use of fertilizers and pesticides.
Improved crop varieties.
Better management practices.
Challenges in developing countries due to high costs.
Organic Agriculture
Focus on natural methods.
Avoidance of synthetic chemicals.
Sustainable farming practices.
Potential benefits for health and the environment.
Genetically Engineered Crop-Based Agriculture
Genetic modification for desired traits.
Increased resistance to pests and diseases.
Potential for higher yields.
Controversies surrounding GMOs.
Comparison and Challenges
Green Revolution's impact on food supply.
Limitations of existing crop varieties.
Affordability and accessibility issues in developing countries.
Conclusion
Need for a balanced approach.
Consideration of environmental and social impacts.
Importance of research and innovation in food production.
Introduction
Traditional breeding techniques vs. tissue culture
Development of tissue culture technology
Definition of Tissue Culture
Regeneration of whole plants from explants
Totipotency: ability to generate a whole plant from any cell/explant
Process of Tissue Culture
Explants: any part of a plant grown in a test tube
Sterile conditions and special nutrient media
Importance of carbon source (sucrose), inorganic salts, vitamins, amino acids, and growth regulators (auxins, cytokinins)
Significance of Tissue Culture
Fast and efficient systems for crop improvement
Potential for generating new plant varieties
Application in higher classes for students to learn
Conclusion
Emphasis on the importance of nutrient medium components
Future prospects and advancements in tissue culture technology
Introduction
Definition of micro-propagation
Production of genetically identical plants (somaclones)
Applications of Tissue Culture
Commercial scale production of food plants (tomato, banana, apple)
Recovery of healthy plants from diseased plants
Meristem Culture
Meristem as virus-free
Culturing meristems of banana, sugarcane, potato
Protoplast Isolation
Isolation of naked protoplasts
Fusion of protoplasts from different varieties to obtain hybrid protoplasts
Somatic Hybridisation
Formation of somatic hybrids
Process of somatic hybridisation
Conclusion
Importance of tissue culture in plant propagation
Potential for creating new plant varieties through somatic hybridisation
Introduction
Fusion of protoplasts of tomato and potato to create pomato
Pomato not meeting desired characteristics for commercial use
Alternative Path for Maximum Yield
Utilizing understanding of genetics for improved crop traits
Development of genetically modified crops for enhanced yield
Minimizing Chemical Usage
Reducing fertilizers and chemicals to mitigate environmental harm
Potential solution: adoption of genetically modified crops
Genetically Modified Organisms (GMOs)
Definition: organisms with altered genes through manipulation
Examples: plants, bacteria, fungi, and animals
Conclusion
GMOs as a potential solution for maximizing yield and reducing chemical usage
Importance of responsible and ethical use of genetically modified crops
.
Introduction
Genetic modification (GM) has been beneficial in various ways in agriculture.
Advantages of Genetic Modification
Increased tolerance to abiotic stresses:
Cold, drought, salt, heat.
Reduced reliance on chemical pesticides:
Pest-resistant crops.
Decreased post-harvest losses.
Enhanced mineral usage efficiency:
Prevents soil fertility exhaustion.
Improved nutritional value:
e.g., Golden rice (Vitamin A enriched).
Applications of Genetic Modification
Tailor-made plants for alternative resources:
Starches, fuels, pharmaceuticals.
Production of pest-resistant plants:
Decreases pesticide usage.
Bt toxin:
Produced by Bacillus thuringiensis (Bt).
Cloned and expressed in plants for insect resistance.
Examples: Bt cotton, Bt corn, rice, tomato, potato, soybean.
Conclusion
Genetic modification in plants offers various benefits in agriculture and food production.
Introduction to Bacillus thuringiensis (Bt)
Mnemonic: "Some Tigers Attack Cute Birds Daily."
Some strains produce proteins that kill certain insects (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes).
Protein crystals contain toxic insecticidal protein
Mechanism of Action
Inactive protoxins converted to active form in insect gut
Activated toxin binds to midgut epithelial cells, causing cell lysis
Resulting in insect death
Incorporation into Crop Plants
Specific Bt toxin genes isolated from Bt
Genes incorporated into crop plants like cotton
Choice of genes depends on crop and targeted pest
Examples of Bt Toxin Genes
cryIAc and cryIIAb control cotton bollworms
cryIAb controls corn borer
Conclusion
Bt cotton offers pest resistance through genetic modification
Provides a sustainable and effective method for insect control
BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE
Let us take a look at the three options that can be thoughtfor increasing food production(i) agro-chemical based agriculture (ii) organic agriculture; and(iii) genetically engineered crop-based agriculture.The Green Revolution succeeded in tripling the food supply but yetit was not enough to feed the growing human population. Increased yieldshave partly been due to the use of improved crop varieties, but mainlydue to the use of better management practices and use of agrochemicals(fertilisers and pesticides). However, for farmers in the developing world,agrochemicals are often too expensive, and further increases in yield withexisting varieties are not possible using conventional breeding.As traditional breeding techniques failed to keep pace with demand andto provide sufficiently fast and efficient systems for crop improvement,another technology called tissue culture got developed. What doestissue culture mean? It was learnt by scientists, during 1950s, thatwhole plants could be regenerated from explants, i.e., any part of aplant taken out and grown in a test tube, under sterile conditions inspecial nutrient media. This capacity to generate a whole plant fromany cell/explant is called totipotency. You will learn how to accomplishthis in higher classes. It is important to stress here that the nutrientmedium must provide a carbon source such as sucrose and alsoinorganic salts, vitamins, amino acids and growth regulators like auxins,cytokinins etc. By application of these methods it is possible to achievepropagation of a large number of plants in very short durations. Thismethod of producing thousands of plants through tissue culture iscalled micro-propagation. Each of these plants will be geneticallyidentical to the original plant from which they were grown, i.e., they aresomaclones. Many important food plants like tomato, banana, apple,etc., have been produced on commercial scale using this method. Try tovisit a tissue culture laboratory with your teacher to better understandand appreciate the process.Another important application of the method is the recovery ofhealthy plants from diseased plants. Even if the plant is infected with avirus, the meristem (apical and axillary) is free of virus. Hence, onecan remove the meristem and grow it in vitro to obtain virus-free plants.Scientists have succeeded in culturing meristems of banana, sugarcane,potato, etc.Scientists have even isolated single cells from plants and afterdigesting their cell walls have been able to isolate naked protoplasts(surrounded by plasma membranes). Isolated protoplasts from twodifferent varieties of plants – each having a desirable character – can befused to get hybrid protoplasts, which can be further grown to form anew plant. These hybrids are called somatic hybrids while the process is called somatic hybridisation. Imagine a situation when a protoplastof tomato is fused with that of potato, and then they are grown – to formnew hybrid plants combining tomato and potato characteristics. Well,this has been achieved – resulting in formation of pomato; unfortunatelythis plant did not have all the desired combination of characteristics forits commercial utilisation.Is there any alternative path that our understanding of genetics canshow so that farmers may obtain maximum yield from their fields? Isthere a way to minimise the use of fertilisers and chemicals so that theirharmful effects on the environment are reduced? Use of geneticallymodified crops is a possible solution.Plants, bacteria, fungi and animals whose genes have been altered bymanipulation are called Genetically Modified Organisms (GMO). GMplants have been useful in many ways. Genetic modification has:(i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat).(ii) reduced reliance on chemical pesticides (pest-resistant crops).(iii) helped to reduce post harvest losses.(iv) increased efficiency of mineral usage by plants (this prevents earlyexhaustion of fertility of soil).(v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’enriched rice.In addition to these uses, GM has been used to create tailor-madeplants to supply alternative resources to industries, in the form of starches,fuels and pharmaceuticals.Some of the applications of biotechnology in agriculture that you willstudy in detail are the production of pest resistant plants, which coulddecrease the amount of pesticide used. Bt toxin is produced by abacterium called Bacillus thuringiensis (Bt for short). Bt toxin gene hasbeen cloned from the bacteria and been expressed in plants to provideresistance to insects without the need for insecticides; in effect created abio-pesticide. Examples are Bt cotton, Bt corn, rice, tomato, potato andsoyabean etc.Bt Cotton: Some strains of Bacillus thuringiensis produce proteins thatkill certain insects such as lepidopterans (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes). B. thuringiensisforms protein crystals during a particular phase of their growth. Thesecrystals contain a toxic insecticidal protein. Why does this toxin not killthe Bacillus? Actually, the Bt toxin protein exist as inactive protoxins butonce an insect ingest the inactive toxin, it is converted into an active formof toxin due to the alkaline pH of the gut which solubilise the crystals.The activated toxin binds to the surface of midgut epithelial cells andcreate pores that cause cell swelling and lysis and eventually cause death Specific Bt toxin genes were isolated from Bacillus thuringiensis andincorporated into the several crop plants such as cotton (Figure 10.1).The choice of genes depends upon the crop and the targeted pest, asmost Bt toxins are insect-group specific. The toxin is coded by a genecryIAc named cry. There are a number of them, for example, the proteinsencoded by the genes cryIAc and cryIIAb control the cotton bollworms,that of cryIAb controls corn borer
Introduction
Overview of the three options for increasing food production.
Agro-chemical Based Agriculture
Use of fertilizers and pesticides.
Improved crop varieties.
Better management practices.
Challenges in developing countries due to high costs.
Organic Agriculture
Focus on natural methods.
Avoidance of synthetic chemicals.
Sustainable farming practices.
Potential benefits for health and the environment.
Genetically Engineered Crop-Based Agriculture
Genetic modification for desired traits.
Increased resistance to pests and diseases.
Potential for higher yields.
Controversies surrounding GMOs.
Comparison and Challenges
Green Revolution's impact on food supply.
Limitations of existing crop varieties.
Affordability and accessibility issues in developing countries.
Conclusion
Need for a balanced approach.
Consideration of environmental and social impacts.
Importance of research and innovation in food production.
Introduction
Traditional breeding techniques vs. tissue culture
Development of tissue culture technology
Definition of Tissue Culture
Regeneration of whole plants from explants
Totipotency: ability to generate a whole plant from any cell/explant
Process of Tissue Culture
Explants: any part of a plant grown in a test tube
Sterile conditions and special nutrient media
Importance of carbon source (sucrose), inorganic salts, vitamins, amino acids, and growth regulators (auxins, cytokinins)
Significance of Tissue Culture
Fast and efficient systems for crop improvement
Potential for generating new plant varieties
Application in higher classes for students to learn
Conclusion
Emphasis on the importance of nutrient medium components
Future prospects and advancements in tissue culture technology
Introduction
Definition of micro-propagation
Production of genetically identical plants (somaclones)
Applications of Tissue Culture
Commercial scale production of food plants (tomato, banana, apple)
Recovery of healthy plants from diseased plants
Meristem Culture
Meristem as virus-free
Culturing meristems of banana, sugarcane, potato
Protoplast Isolation
Isolation of naked protoplasts
Fusion of protoplasts from different varieties to obtain hybrid protoplasts
Somatic Hybridisation
Formation of somatic hybrids
Process of somatic hybridisation
Conclusion
Importance of tissue culture in plant propagation
Potential for creating new plant varieties through somatic hybridisation
Introduction
Fusion of protoplasts of tomato and potato to create pomato
Pomato not meeting desired characteristics for commercial use
Alternative Path for Maximum Yield
Utilizing understanding of genetics for improved crop traits
Development of genetically modified crops for enhanced yield
Minimizing Chemical Usage
Reducing fertilizers and chemicals to mitigate environmental harm
Potential solution: adoption of genetically modified crops
Genetically Modified Organisms (GMOs)
Definition: organisms with altered genes through manipulation
Examples: plants, bacteria, fungi, and animals
Conclusion
GMOs as a potential solution for maximizing yield and reducing chemical usage
Importance of responsible and ethical use of genetically modified crops
.
Introduction
Genetic modification (GM) has been beneficial in various ways in agriculture.
Advantages of Genetic Modification
Increased tolerance to abiotic stresses:
Cold, drought, salt, heat.
Reduced reliance on chemical pesticides:
Pest-resistant crops.
Decreased post-harvest losses.
Enhanced mineral usage efficiency:
Prevents soil fertility exhaustion.
Improved nutritional value:
e.g., Golden rice (Vitamin A enriched).
Applications of Genetic Modification
Tailor-made plants for alternative resources:
Starches, fuels, pharmaceuticals.
Production of pest-resistant plants:
Decreases pesticide usage.
Bt toxin:
Produced by Bacillus thuringiensis (Bt).
Cloned and expressed in plants for insect resistance.
Examples: Bt cotton, Bt corn, rice, tomato, potato, soybean.
Conclusion
Genetic modification in plants offers various benefits in agriculture and food production.
Introduction to Bacillus thuringiensis (Bt)
Mnemonic: "Some Tigers Attack Cute Birds Daily."
Some strains produce proteins that kill certain insects (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes).
Protein crystals contain toxic insecticidal protein
Mechanism of Action
Inactive protoxins converted to active form in insect gut
Activated toxin binds to midgut epithelial cells, causing cell lysis
Resulting in insect death
Incorporation into Crop Plants
Specific Bt toxin genes isolated from Bt
Genes incorporated into crop plants like cotton
Choice of genes depends on crop and targeted pest
Examples of Bt Toxin Genes
cryIAc and cryIIAb control cotton bollworms
cryIAb controls corn borer
Conclusion
Bt cotton offers pest resistance through genetic modification
Provides a sustainable and effective method for insect control
BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE
Let us take a look at the three options that can be thoughtfor increasing food production(i) agro-chemical based agriculture (ii) organic agriculture; and(iii) genetically engineered crop-based agriculture.The Green Revolution succeeded in tripling the food supply but yetit was not enough to feed the growing human population. Increased yieldshave partly been due to the use of improved crop varieties, but mainlydue to the use of better management practices and use of agrochemicals(fertilisers and pesticides). However, for farmers in the developing world,agrochemicals are often too expensive, and further increases in yield withexisting varieties are not possible using conventional breeding.As traditional breeding techniques failed to keep pace with demand andto provide sufficiently fast and efficient systems for crop improvement,another technology called tissue culture got developed. What doestissue culture mean? It was learnt by scientists, during 1950s, thatwhole plants could be regenerated from explants, i.e., any part of aplant taken out and grown in a test tube, under sterile conditions inspecial nutrient media. This capacity to generate a whole plant fromany cell/explant is called totipotency. You will learn how to accomplishthis in higher classes. It is important to stress here that the nutrientmedium must provide a carbon source such as sucrose and alsoinorganic salts, vitamins, amino acids and growth regulators like auxins,cytokinins etc. By application of these methods it is possible to achievepropagation of a large number of plants in very short durations. Thismethod of producing thousands of plants through tissue culture iscalled micro-propagation. Each of these plants will be geneticallyidentical to the original plant from which they were grown, i.e., they aresomaclones. Many important food plants like tomato, banana, apple,etc., have been produced on commercial scale using this method. Try tovisit a tissue culture laboratory with your teacher to better understandand appreciate the process.Another important application of the method is the recovery ofhealthy plants from diseased plants. Even if the plant is infected with avirus, the meristem (apical and axillary) is free of virus. Hence, onecan remove the meristem and grow it in vitro to obtain virus-free plants.Scientists have succeeded in culturing meristems of banana, sugarcane,potato, etc.Scientists have even isolated single cells from plants and afterdigesting their cell walls have been able to isolate naked protoplasts(surrounded by plasma membranes). Isolated protoplasts from twodifferent varieties of plants – each having a desirable character – can befused to get hybrid protoplasts, which can be further grown to form anew plant. These hybrids are called somatic hybrids while the process is called somatic hybridisation. Imagine a situation when a protoplastof tomato is fused with that of potato, and then they are grown – to formnew hybrid plants combining tomato and potato characteristics. Well,this has been achieved – resulting in formation of pomato; unfortunatelythis plant did not have all the desired combination of characteristics forits commercial utilisation.Is there any alternative path that our understanding of genetics canshow so that farmers may obtain maximum yield from their fields? Isthere a way to minimise the use of fertilisers and chemicals so that theirharmful effects on the environment are reduced? Use of geneticallymodified crops is a possible solution.Plants, bacteria, fungi and animals whose genes have been altered bymanipulation are called Genetically Modified Organisms (GMO). GMplants have been useful in many ways. Genetic modification has:(i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat).(ii) reduced reliance on chemical pesticides (pest-resistant crops).(iii) helped to reduce post harvest losses.(iv) increased efficiency of mineral usage by plants (this prevents earlyexhaustion of fertility of soil).(v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’enriched rice.In addition to these uses, GM has been used to create tailor-madeplants to supply alternative resources to industries, in the form of starches,fuels and pharmaceuticals.Some of the applications of biotechnology in agriculture that you willstudy in detail are the production of pest resistant plants, which coulddecrease the amount of pesticide used. Bt toxin is produced by abacterium called Bacillus thuringiensis (Bt for short). Bt toxin gene hasbeen cloned from the bacteria and been expressed in plants to provideresistance to insects without the need for insecticides; in effect created abio-pesticide. Examples are Bt cotton, Bt corn, rice, tomato, potato andsoyabean etc.Bt Cotton: Some strains of Bacillus thuringiensis produce proteins thatkill certain insects such as lepidopterans (tobacco budworm, armyworm),coleopterans (beetles) and dipterans (flies, mosquitoes). B. thuringiensisforms protein crystals during a particular phase of their growth. Thesecrystals contain a toxic insecticidal protein. Why does this toxin not killthe Bacillus? Actually, the Bt toxin protein exist as inactive protoxins butonce an insect ingest the inactive toxin, it is converted into an active formof toxin due to the alkaline pH of the gut which solubilise the crystals.The activated toxin binds to the surface of midgut epithelial cells andcreate pores that cause cell swelling and lysis and eventually cause death Specific Bt toxin genes were isolated from Bacillus thuringiensis andincorporated into the several crop plants such as cotton (Figure 10.1).The choice of genes depends upon the crop and the targeted pest, asmost Bt toxins are insect-group specific. The toxin is coded by a genecryIAc named cry. There are a number of them, for example, the proteinsencoded by the genes cryIAc and cryIIAb control the cotton bollworms,that of cryIAb controls corn borer
