Genetic Engineering and Biotechnology

With reference to agriculture in India, how can the technique of ‘genome sequencing’, often seen in the news, be used in the immediate future ?

• 1. Genome sequencing can be used to identify genetic markers for disease resistance and drought tolerance in various crop plants.
• 2. This technique helps in reducing the time required to develop new varieties of crop plants.
• 3. It can be used to decipher the host-pathogen relationships in crops.

Select the correct answer using the code given below :

[amp_mcq option1=”1 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

The correct answer is D) 1, 2 and 3.

Genome sequencing provides the complete genetic blueprint of an organism.
1. By sequencing genomes of different crop varieties and wild relatives, researchers can identify genes or genetic markers associated with desirable traits like resistance to diseases or tolerance to drought. This information is crucial for marker-assisted selection and breeding programs. Thus, statement 1 is correct.
2. Knowing the genetic basis of traits allows breeders to make more informed selections early in the breeding process, reducing the need for extensive field trials for each generation. This targeted approach, enabled by genomic data, can significantly shorten the time required to develop new, improved crop varieties compared to traditional breeding methods. Thus, statement 2 is correct.
3. Genome sequencing can be applied to both the host plant and the pathogens that infect it (e.g., fungi, bacteria, viruses, insects). By sequencing the genomes of pathogens, scientists can understand their virulence factors, mechanisms of infection, and evolution. Sequencing the host genome reveals genes involved in defense responses. Comparing and analyzing these genomes helps decipher the complex interactions and relationships between the host plant and its pathogens, which is vital for developing resistant varieties or disease management strategies. Thus, statement 3 is correct.

Genome sequencing is a powerful tool in modern agriculture, contributing to increased yield, improved nutritional content, enhanced resilience to environmental stresses, and reduced reliance on pesticides and herbicides through the development of superior crop varieties. These applications are already in use or are in advanced stages of research and development, making them relevant for the “immediate future” of agriculture.

In the context of the developments in Bioinformatics, the term ‘transcriptome’, sometimes seen in the news, refers to

[amp_mcq option1=”a range of enzymes used in genome editing” option2=”the full range of mRNA molecules expressed by an organism” option3=”the description of the mechanism of gene expression” option4=”a mechanism of genetic mutations taking place in cells” correct=”option2″]

In Bioinformatics, the term ‘transcriptome’ refers to the complete set of messenger RNA (mRNA) molecules expressed by an organism or in a specific cell population at a given time.

– The genome is the complete set of DNA in an organism. Genes within the genome are transcribed into messenger RNA (mRNA) molecules during the process of gene expression.
– The transcriptome represents all the mRNA transcripts present in a cell or tissue. Studying the transcriptome allows researchers to understand which genes are actively being expressed under specific conditions.

– Option A describes enzymes involved in techniques like CRISPR, which manipulate the genome.
– Option C describes the *process* of gene expression (transcription, translation), not the resulting set of mRNA molecules.
– Option D describes changes in the DNA sequence itself, which can affect the resulting transcriptome but is not what the term ‘transcriptome’ refers to.
– Transcriptomics is the study of the transcriptome and is a key area of research in molecular biology and bioinformatics, providing insights into cellular function, development, and disease.

Consider the following techniques/ phenomena:

• 1. Budding and grafting in fruit plants
• 2. Cytoplasmic male sterility
• 3. Gene silencing

Which of the above is/are used to create transgenic crops?

[amp_mcq option1=”1 only” option2=”2 and 3″ option3=”1 and 3″ option4=”None” correct=”option2″]

The correct answer is B) 2 and 3. Transgenic crops are created through genetic engineering, which involves introducing or altering genes in a plant.

1. Budding and grafting in fruit plants: These are methods of asexual (vegetative) propagation used to combine traits from different plants or propagate desired varieties. They do not involve introducing foreign genes to create a transgenic organism. This is not used to create transgenic crops.
2. Cytoplasmic male sterility: While CMS itself is a biological phenomenon used in hybrid breeding, genetic engineering techniques *can* be used to introduce or restore male sterility genes (like the barnase/barstar system), thereby creating transgenic plants with engineered CMS. In this context, the concept is linked to the creation of transgenics for breeding purposes.
3. Gene silencing: Techniques like RNA interference (RNAi) are methods of gene silencing where the expression of a specific gene is inhibited. These techniques are widely used in genetic engineering to modify plants, for example, to reduce levels of undesirable compounds, improve nutritional value, or confer resistance. Using gene silencing to modify a plant *creates* a transgenic crop.

Creating transgenic crops involves techniques for gene isolation, vector construction, gene transfer (e.g., Agrobacterium-mediated transformation, gene gun), and selection of transformed cells/plants. Gene silencing is a tool used in the genetic modification process. While CMS is a trait, the methods to engineer it into a plant fall under genetic engineering techniques used for creating transgenics.

Mycorrhizal biotechnology has been used in rehabilitating degraded sites because mycorrhiza enables the plants to

• 1. resist drought and increase absorptive area
• 2. tolerate extremes of pH
• 3. resist disease infestation

Select the correct answer using the codes given below:

[amp_mcq option1=”1 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

Mycorrhizal associations significantly benefit plants, especially in challenging or degraded environments, by improving their ability to absorb water and nutrients, tolerate harsh soil conditions (including pH extremes), and resist diseases. Therefore, all three statements are correct.

Mycorrhizal fungi form symbiotic relationships with plant roots. The fungal hyphae extend far into the soil, vastly increasing the surface area for absorption of water and nutrients (particularly phosphorus and nitrogen) beyond what the plant’s root hairs can reach. This enhanced absorption capacity helps plants cope with drought stress. Mycorrhizae can also modify the rhizosphere environment and interact with soil microbes, improving plant tolerance to soil acidity/alkalinity and heavy metals, and enhancing resistance to root pathogens.

Mycorrhizal biotechnology is increasingly used in ecological restoration and sustainable agriculture due to these multifaceted benefits to plant health and resilience, reducing the need for irrigation, fertilizers, and pesticides.

Recombinant DNA technology (Genetic Engineering) allows genes to be transferred

• 1. across different species of plants
• 2. from animals to plants
• 3. from microorganisms to higher organisms

Select the correct answer using the codes given below.

[amp_mcq option1=”1 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

Recombinant DNA technology allows genes to be transferred across different species and even kingdoms. All three statements describe possible applications of this technology.

1. Transfer across different species of plants: Yes, this is common in developing Genetically Modified (GM) crops, for example, transferring herbicide resistance genes between plant species or varieties.
2. From animals to plants: Yes, while perhaps not as common as plant-to-plant or microorganism-to-plant transfers for agricultural purposes, it is technically possible to transfer genes from animals to plants using genetic engineering techniques. This has been explored in research for various purposes.
3. From microorganisms to higher organisms: Yes, this is a very common application. For instance, transferring genes from bacteria (like the Bt gene) to plants for pest resistance (e.g., Bt cotton), or inserting genes from humans into bacteria or yeast for the production of therapeutic proteins like insulin.

Recombinant DNA technology involves techniques like gene cloning and transformation, allowing scientists to isolate a gene from one organism and introduce it into another organism, often unrelated, to express a desired trait or produce a specific product. This technology has vast applications in agriculture, medicine, and industry.