Bt Crops: Definition, Types, Examples, Diagram, Questions, Process
Bt crops are a category of genetically modified plants that are engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt). These crops, such as Bt cotton and Bt maize, are designed to resist insect pests like bollworms, reducing the use of chemical pesticides. This approach reflects biotechnology and its application in agriculture.
This Story also Contains
- What are Bt crops?
- Mechanism of Bt Toxin in Pest Control
- Types of Bt Crops
- Advantages of Bt Crops
- Disadvantages of Bt Crops
- Bt Crops and Global Agriculture
- Future Prospects of Bt Crops
- MCQs on Bt Crops
- Frequently Asked Questions (FAQs)
- Recommended video for Bt Crops
By incorporating Bt genes into the plant genome, scientists have enabled these crops to produce toxins that target insect larvae but are safe for humans and other animals. This innovation in agriculture biotechnology helps in protecting crops from damage. It also contributes to better yields, reduced input costs, and promotes eco-friendly agricultural practices.
What are Bt crops?
Bt crops are transgenic plants genetically engineered with the DNA of the Bacillus thuringiensis bacteria. Bt crops are genetically modified to include the insecticidal proteins of Bacillus thuringiensis. The most common Bt crops include Bt cotton and Bt maize, which have been widely adopted for their pest-resistant properties.
Bacillus thuringiensis: The Bacterium Behind Bt Crops
Bacillus thuringiensis is a soil bacterium that produces certain proteins toxic to specific kinds of insects. This is one of the best examples of Bt crops. The toxins produced by Bt bind to the receptors in the gut of the target insects, causing cell lysis and death, providing a natural pest control mechanism.
Mechanism of Bt Toxin in Pest Control
Bt crops produce a protein known as Cry toxin, derived from the Bacillus thuringiensis. When ingested by certain insect pests, it leads to cell lysis and death of the insect. This reduces the need for external chemical pesticides. Following are the steps by which the Bt toxin can work:
Ingestion: Target pests ingest Bt proteins while feeding on the plant.
Binding: The Bt toxin binds to specific receptors in the insect's gut.
Cell Lysis: The binding causes the plasma membrane to break down, leading to gut paralysis and eventual death of the insect.
Diagram of Bt Cotton
Development of Bt Crops
Advanced techniques of biotechnology are incorporated in developing Bt crops, such as
Bt Gene Isolation: The gene involved in the production of Bt toxin is isolated from the bacterium.
Transferring of Bt Gene: The Bt gene is transferred into the plant genome by the vectors.
Selection: The selection of plants that are successfully transformed for the further plant breeding process, leads to their development.
Types of Bt Crops
Different types of Bt crops are developed to resist specific insect pests. Examples of Bt crops include Bt cotton, Bt brinjal, Bt maize, and Bt soybean. Each crop is genetically modified for targeting the pests affecting that plant. The types of Bt Crops are listed below:
Bt Crop | Targeted Pests | Advantages |
Bt Cotton | Bollworm, pink bollworm | Reduces the use of pesticides, enhancing crop yield |
Bt Maize | European corn borer, rootworm | Provides better crop protection with increased productivity |
Bt Brinjal | Fruit and shoot borer | Reduces pest damage, improves fruit quality |
Advantages of Bt Crops
Bt crops have several advantages. They help protect plants from harmful insects. They lower the use of agriculture fertilizers, which benefits the environment. These crops increase yield and are better quality. The advantages of Bt Crops are listed below-
Enhanced Pest Resistance: Bt crops provide effective resistance to target insect pests, thus minimizing crop losses and maximizing agricultural outputs.
Reduced Need for Chemical Pesticides: Bt crops reduce the use of chemical pesticides, leading to a safer environment.
Increased Crop Yield and Quality: Benefits to the farmers in terms of better yield and quality of crops due to effective control of pests by Bt crops.
Environmental Benefits: Diminished use of chemical pesticides will reduce the different types of pollution and enhance biodiversity.
Disadvantages of Bt Crops
Bt crops come with a few disadvantages. There is a risk of pests developing resistance over time. There is a huge concern about the ecological impact. Some countries have banned growing Bt crops. The disadvantages of Bt Crops are listed below-
Development of Pest Resistance: Continuous use of Bt toxins may develop resistance in the target pest populations, and thereby, IPM will be required.
Impact on Non-Target Organisms: Potential impact of Bt crops on nontarget organisms such as beneficial insects and soil microorganisms may be impacted.
Biodiversity Concern: Local biodiversity may be affected due to the popularization of Bt crops if non-targets are affected, and genetic diversity among crops may be reduced.
Ethical and Regulatory Issues: Bt crops are the products of GMOs and raise concerns regarding their ethical nature and their rigorous clearance from various regulatory bodies to be safe for human beings and the environment.
Diagram: Potential Ecological Impacts Of Bt Crops
Bt Crops and Global Agriculture
Bt crops are cultivated in several countries and have become part of sustainable farming practices. They contribute to higher food production and reduced pesticide usage. However, their acceptance varies globally. Adoption Rates Worldwide of Bt Crops are discussed below:
The global adoption of Bt crops has been monitored and recorded with the following remarkable success stories.
Bt Cotton in India led to a significant reduction in pesticide use and an increase in yields.
Bt corn in the United States is observed to increase crop health and yield.
Economic Impacts on Farmers
Economic gains for farmers adopting Bt crops include reduction in costs of pesticides and a considerable increment in crop yields hence bettering their economic status.
Regulatory Framework and Safety Assessment
When new Bt crops are developed, they are passed through safety tests and efficacy trials by regulatory bodies. The registration phase for Bt crops must pass through rigorous field evaluations, laboratory and extensive risk assessment. As a result, there have been no significant studies implicating long-term human health and environmental effects on Bt crops, and they can be used continually in agriculture.
Future Prospects of Bt Crops
Research is still ongoing in Bt, developing new varieties with strong traits and resistance to a wider range of pests. Their role in the agriculture system can continuously be enhanced through Bt stacking and integration with other sustainable farming practices, such as crop rotation and biological controls, to enhance agricultural sustainability.
MCQs on Bt Crops
Q1. Bt cotton has gained significant media attention lately, and its prefix, 'Bt,' refers to:
Cotton seeds are referred to as “Barium-treated.”
A cotton variety with a “bigger thread” size and improved tensile strength.
Created through the utilization of biotechnology, involving restriction enzymes and ligases.
Incorporating an endotoxin gene derived from Bacillus thuringiensis.
Correct answer: 4) Incorporating an endotoxin gene derived from Bacillus thuringiensis
Explanation:
By inserting the gene that produces the Cry toxin from Bacillus thuringiensis, scientists have genetically altered the cotton plant in the instance of Bt cotton. The cotton plant can create the poison itself thanks to this genetic change, which increases its resistance to specific insect pests. Ingesting the toxin while feeding on the Bt cotton causes the bugs' digestive systems to malfunction, ultimately resulting in their demise.
By introducing the endotoxin gene from Bacillus thuringiensis, Bt cotton is naturally protected from some insect pests, which lessens the need for heavy pesticide use and offers a more ecologically friendly method of managing pests in cotton production.
Hence, the correct answer is option 4) Incorporating an endotoxin gene derived from Bacillus thuringiensis.
Q2. Assertion: The production of the protein toxin trioxide by the bacterium Bacillus thuringiensis exhibits efficacy against various insect groups.
Reason: The mechanism of action involves the conversion of the toxin into an active form upon ingestion by susceptible insects, resulting in their demise through the inhibition of ion transport in the midgut.
Both Assertion & Reason are True &the Reason is a correct explanation of the Assertion.
Both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
Assertion is true but the reason is false.
Both Assertion & Reason are false.
Correct answer: 1) Both Assertion & Reason are True &the Reason is a correct explanation of the Assertion.
Explanation:
The assertion states that the production of the protein toxin trioxide by Bacillus thuringiensis is effective against various insect groups. This is true as Bacillus thuringiensis is known for its insecticidal properties, and the production of toxins such as trioxide contributes to its efficacy against different insect pests.
The reason explains the mechanism of action behind this efficacy. It states that the toxin is converted into an active form upon ingestion by susceptible insects. This conversion leads to the inhibition of ion transport in the midgut, ultimately resulting in the demise of the insects. This explanation is also correct as the active form of the toxin interferes with ion transport, disrupting the normal functioning of the midgut and leading to insect mortality. Therefore, both the assertion and the reason are true, and the reason provides a correct explanation for the assertion.
Hence, the correct answer is option (1) Both Assertion & Reason are True &the Reason is a correct explanation of the Assertion.
Q3. Some of the characteristics of Bt cotton are:
long fibre and resistance to aphids
medium yield, long fiber and resistance to beetle pests
high yield and production of toxic protein crystals which kill dipteran pests
high yield and resistance to bollworms
Correct answer: 4) high yield and resistance to bollworms
Explanation:
Genetically modified crops (GMOs) are transgenic plants that contain and express one or more beneficial foreign genes or transgenes. Food prepared from these genetically modified crops is referred to as genetically modified food. Examples include Bt cotton and Flavr Savr tomatoes. Transgenic plants, often described as bioreactors or factories, can produce specific products. For instance, Bt cotton is a genetically modified crop known for its high yield and resistance to bollworms.
Hence, the correct answer is option 4) high yield and resistance to bollworms.
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Frequently Asked Questions (FAQs)
Q1. What does Bt mean in crops?
Bt stands for Bacillus thuringiensis, a bacterium whose gene is inserted into crops to make them resistant to pests.
Q2. Why are Bt crops banned in India?
Bt crops are banned due to concerns about environmental safety, biodiversity loss, and lack of sufficient long-term studies.
Q3. Which is the first Bt crop?
Bt cotton was the first Bt crop commercially grown in India.
Q4. What are a few examples of a Bt plant?
A few examples of Bt plants include Bt cotton, Bt maize (corn), Bt brinjal, and Bt soybean.
Q5. Which crop is called the golden fibre in India?
Jute is called the golden fibre in India. It gets this name due to its golden colour and high economic value.
Recommended video for Bt Crops
Frequently Asked Questions (FAQs)
Extensive safety evaluations conducted by the regulatory authorities have confirmed the safety of Bt crops to humans and the environment.
Major risks associated with Bt crops include resistance development in target pests, risk to non-target organisms, and the biodiversity impact.
Bt crops produce a protein that, when ingested by specific classes of insects will bind to the cells in the gut. This will lead to the rupture of cells and eventually death.
Reduced usage of insecticides, higher yield of crops, and better crop quality.