Biotechnological Applications in Agriculture Questions in English

(B) The $CryIAb$ gene is derived from the bacterium $Bacillus \text{ } thuringiensis$.
This gene encodes a specific crystal protein (toxin) that is toxic to certain insect larvae.
In maize plants, the expression of the $CryIAb$ gene provides resistance against the corn borer, which is a major pest of maize crops.
Therefore, the correct option is $B$.

(A) $Bacillus \text{ } thuringiensis$ $(Bt)$ produces a specific insecticidal protein known as the $Cry$ protein. This protein is encoded by the $cry$ gene. It exists in an inactive protoxin form within the bacterium, which becomes active in the alkaline gut environment of the target insect, leading to its death.

(C) The genes $CryIAc$ and $CryIIAb$ are derived from the bacterium $Bacillus \text{ } thuringiensis$ $(Bt)$.
These specific genes encode for crystal proteins that are toxic to specific insect pests.
Specifically, $CryIAc$ and $CryIIAb$ are used to control cotton bollworms.
Therefore, the correct option is $C$.

(D) The $Bt$ toxin produced by the bacterium $Bacillus$ $thuringiensis$ is ingested by the insect larvae.
In the alkaline environment of the insect's $midgut$, the inactive protoxin is converted into its active form.
The activated toxin binds to the surface of the epithelial cells of the $midgut$ and creates pores.
This causes cell swelling and lysis, eventually leading to the death of the insect.

(B) The $Cry$ proteins produced by $Bacillus \text{ } thuringiensis$ $(Bt)$ are insecticidal proteins.
When an insect ingests the inactive protoxin, it is converted into its active form due to the alkaline $pH$ of the gut.
The activated toxin binds to the surface of the midgut epithelial cells.
This binding creates pores in the cell membrane, which causes cell swelling and lysis, eventually leading to the death of the insect.

(A) $Bt$ cotton is a genetically modified $(GM)$ crop.
It is created by inserting the $cry$ genes from the bacterium $Bacillus$ $thuringiensis$ into the cotton genome.
These genes produce insecticidal proteins that provide resistance against specific pests like bollworms, thereby reducing the need for chemical pesticides.

(B) The nematode $Meloidogyne incognita$ infects the roots of tobacco plants and causes a great reduction in yield.
To prevent this infection, a strategy based on the process of $RNA$ interference $(RNAi)$ was adopted.
$RNAi$ takes place in all eukaryotic organisms as a method of cellular defense.
This method involves silencing of a specific $mRNA$ due to a complementary $dsRNA$ molecule that binds to and prevents translation of the $mRNA$ (silencing).

(C) The method used to make tobacco plants resistant to pests is $RNA$ interference $(RNAi)$.
$RNAi$ is a cellular defense mechanism in all eukaryotic organisms.
In this process,a specific $mRNA$ of the pest is silenced by using a complementary double-stranded $RNA$ $(dsRNA)$ molecule.
This $dsRNA$ prevents the translation of the target $mRNA$,thereby preventing the pest from surviving on the transgenic tobacco plant.

(C) $RNAi$ stands for $RNA$ interference.
It is a biological process in which $RNA$ molecules inhibit gene expression or translation,by neutralizing targeted $mRNA$ molecules.
This mechanism is used as a method of cellular defense against double-stranded $RNA$ $(dsRNA)$ viruses and in regulating gene expression.

(D) $RNAi$ ($RNA$ interference) is a method of cellular defense in all eukaryotic organisms.
In this process,a specific $mRNA$ is silenced by a complementary $dsRNA$ (double-stranded $RNA$) molecule.
The $dsRNA$ prevents the translation of the target $mRNA$ into protein,thereby silencing the gene expression.
This technique is widely used in biotechnology,for example,to protect tobacco plants from nematode infection.

(A) $RNA$ interference $(RNAi)$ is a biological process in which $RNA$ molecules inhibit gene expression or translation,by neutralizing targeted $mRNA$ molecules.
In all eukaryotic organisms,this mechanism serves as a method of cellular defense.
It protects the genome against mobile genetic elements such as transposons and viruses,which often produce double-stranded $RNA$ during their replication cycles.

(C) The organism that infects the roots of tobacco plants is a nematode named $Meloidogyne \text{ } incognita$. This infection causes a significant reduction in the yield of tobacco plants. To prevent this, $RNA$ interference $(RNAi)$ technology is used to create pest-resistant plants.

(C) The $GEAC$ stands for $Genetic$ $Engineering$ $Approval$ $Committee$.
This is an organization set up by the Indian government to make decisions regarding the validity of $Genetically$ $Modified$ $(GM)$ research and the safety of introducing $GM$-organisms for public services.

(B) Basmati rice is a unique variety of rice indigenous to India. It is globally renowned for its distinct flavor and rich aroma. In $1997$,an American company got patent rights on Basmati rice through the $US$ Patent and Trademark Office,which led to significant controversy regarding biopiracy.

(C) In India,there are $27$ documented varieties of Basmati rice that are grown. These varieties are distinct and have been cultivated for many centuries in the specific geographical regions of the Indo-Gangetic plains.

(C) The correct matches are as follows:
$(a)$ $Bacillus \text{ } thuringiensis$ produces $Cry \text{ } protein$, which is used as a biopesticide $(a-2)$.
$(b)$ $Meloidogyne \text{ } incognitia$ is a nematode that infects the roots of tobacco plants $(b-1)$.
$(c)$ $Agrobacterium \text{ } tumefaciens$ contains $Ti \text{ } plasmid$ (Tumor inducing plasmid), which is used as a vector in genetic engineering $(c-4)$.
$(d)$ $E. \text{ } coli$ is widely used in biotechnology for the production of genetically engineered insulin $(d-3)$.
Therefore, the correct sequence is $a-2, b-1, c-4, d-3$.

(D) The correct answer is $D$.
Statement $A$ is true: Biotechnology has wide applications in medicine,diagnostics,agriculture,and environmental cleanup (bioremediation).
Statement $B$ is true: The European Federation of Biotechnology $(EFB)$ has given a definition of biotechnology that encompasses both traditional and modern molecular biotechnology.
Statement $C$ is true: Food production can be increased through these three methods.
Statement $D$ is false: While genetically modified $(GM)$ crops help reduce chemical usage,they are not the 'only' possible solution. Integrated pest management,organic farming,and sustainable agricultural practices are also viable solutions.

(NONE) Analysis of the given statements:
$A$. Genetic modification can make crops more tolerant to abiotic stresses such as cold,drought,salt,and heat. This statement is correct.
$B$. Golden rice is a genetically modified $(GM)$ variety of rice enriched with Vitamin-$A$. This statement is correct.
$C$. $Bt$ toxin protein is synthesized by the bacterium as an inactive protoxin,which becomes active due to the alkaline $pH$ in the gut of the insect. This statement is correct.
$D$. Genetic modification can reduce post-harvest losses,for example,by increasing the shelf-life of fruits. This statement is also correct.
Conclusion: All the provided statements are scientifically accurate. Therefore,there is no incorrect statement among the options.

(D) Golden rice is a genetically modified variety of rice $(Oryza\, sativa)$.
It is engineered to produce $\beta-$carotene,which is a precursor of Vitamin $A$,in the edible parts of the rice.
This modification was introduced to address Vitamin $A$ deficiency in populations that rely on rice as a staple food source.

(C) Option $(C)$ is the correct answer.
$RNA$ interference $(RNAi)$ is a method of cellular defense used in many eukaryotic organisms.
In biotechnology,this method has been successfully used to develop transgenic tobacco plants that are resistant to the nematode $Meloidogyne$ $incognita$,which infects the roots of tobacco plants.
The process involves silencing specific $mRNA$ of the nematode using a complementary $dsRNA$ molecule,thereby preventing the nematode from surviving in the host plant.
While other methods exist for reducing post-harvest losses or developing abiotic stress tolerance,$RNAi$ is specifically utilized for pest resistance in this context.

(A) The $Bt$ toxin genes are isolated from $Bacillus \text{ } thuringiensis$ and incorporated into several crop plants.
Specifically, the genes $cry \text{ } I \text{ } Ac$ and $cry \text{ } II \text{ } Ab$ are incorporated into cotton to provide resistance against cotton bollworms.
Similarly, the gene $cry \text{ } I \text{ } Ab$ is introduced into corn to protect it from the corn borer.
Therefore, $cry \text{ } II \text{ } Ab$ controls cotton bollworms and $cry \text{ } I \text{ } Ab$ controls corn borer.

(B) Hairy root disease is an infectious plant disease that primarily affects dicotyledonous plants.
It is caused by the soil-borne bacterium $Agrobacterium$ $rhizogenes$.
This bacterium transfers a portion of its $Ri$ (root-inducing) plasmid into the plant genome,which leads to the proliferation of adventitious roots,commonly known as hairy roots.

(C) The environment in a hydroponics greenhouse is tightly controlled for maximum efficiency. This approach to agricultural production is known as $CEA$ (Controlled Environment Agriculture).

(D) Contamination in hydroponics can be reduced by:
$1$. Changing the nutrient medium regularly (e.g.,weekly) to prevent the accumulation of pathogens and waste products.
$2$. Avoiding the use of tools from outdoor gardens to prevent the introduction of soil-borne pathogens,pests,or contaminants into the controlled hydroponic environment.
$3$. Ensuring complete and proper aeration in the hydroponic tank to maintain optimal oxygen levels for root respiration and to prevent the growth of anaerobic bacteria that can cause root rot.

(C) $Bacillus$ $thuringiensis$ $(Bt)$ strains produce specific insecticidal proteins (Cry proteins).
Scientists have successfully introduced these $Bt$ toxin genes into various crop plants such as cotton,corn,and brinjal through genetic engineering.
These genetically modified plants are capable of producing their own toxins,which kill specific insect pests,thereby acting as bio-insecticidal plants.

(A) $Gossypium$ $hirsutum$ is an American (New World) cotton crop.
It is an allotetraploid species with a chromosome number of $2n = 52$,which means it has $26$ pairs of chromosomes.
Therefore,it is classified as a New World tetraploid.

(D) All the given statements are correct.
$I.$ $Bacillus$ $thuringiensis$ $(Bt)$ is a bacterium used as a bio-control agent to manage butterfly caterpillars.
$II.$ The spores of $Bt$ are available in sachets as dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees.
$III.$ When these spores are ingested by the insect larvae,the toxin is released in the gut due to the alkaline $pH$ of the gut,which kills the larvae.
$IV.$ Through genetic engineering,$Bt$ toxin genes have been introduced into various crop plants (like $Bt$ cotton) to provide inherent resistance to pests.

(A) In terminator gene technology,a specific gene known as the terminator gene is introduced into the plant genome. This gene prevents the production of viable seeds after the first generation of harvest. Consequently,the seeds produced by these plants cannot germinate if replanted,ensuring that the seed producer maintains a monopoly over the specific crop variety.

(D) The genetically-modified $(GM)$ brinjal,commonly known as $Bt$ brinjal,was developed in India to provide resistance against the fruit and shoot borer insect ($Leucinodes$ $orbonalis$).
This was achieved by introducing the $cry1Ac$ gene from the soil bacterium $Bacillus$ $thuringiensis$ $(Bt)$ into the brinjal genome.
The $cry$ genes encode for crystal proteins that are toxic to specific insect larvae,thereby reducing the need for chemical pesticides.

(D) The $Ti$ plasmid (Tumor-inducing plasmid) derived from $Agrobacterium$ $tumefaciens$ is a powerful tool in plant biotechnology.
However, a significant limitation is that it naturally infects only dicotyledonous plants.
It does not infect monocotyledonous cereal plants such as rice, corn, wheat, barley, and maize.
Broad-leaf plants and fruit-bearing plants are mostly dicotyledonous and are susceptible to infection by the $Ti$ plasmid.
Furthermore, it is capable of transmitting prokaryotic genes into the host plant genome.

(D) Agrobacterium tumefaciens: It is a soil bacterium that naturally infects plants. It contains a tumor-inducing $(Ti)$ plasmid. This plasmid can transfer a specific segment of $DNA$,known as $T-DNA$,into the nuclear genome of plant cells,causing tumor formation. Scientists have modified this $Ti$ plasmid to act as a vector for delivering genes of interest into plants,making it a crucial tool in the production of transgenic plants.

(B) Insect-resistant transgenic cotton is produced through genetic engineering by inserting a specific piece of $DNA$ from the bacterium $Bacillus$ $thuringiensis$.
This bacterium produces insecticidal proteins that are toxic to certain pests.
Consequently,this cotton is known as transgenic cotton or $Bt$ cotton,which provides inherent resistance against the cotton bollworm.

(A) $Bacillus$ $thuringiensis$ is a natural insecticide with unique properties that make it useful for pest control. It produces protein crystals (Cry protein, encoded by the $cry$ gene) which contain a toxic insecticidal protein. Crops that are genetically modified with the $Bt$ toxin $cry$ gene produce this toxin within their own cells to protect against insects, thereby eliminating the need for external insecticides.

(C) The bacterium $Bacillus$ $thuringiensis$ is a common soil bacterium,which produces a protein toxin that kills certain insects.
This toxin is a crystal $(Cry)$ protein.
There are several kinds of $cry$ toxins which are toxic to different groups of insects.
The gene encoding the $Cry$ protein is called the $cry$ gene.

(C) Biotechnology has significantly transformed various sectors,but its most extensive and impactful application is found in the field of agriculture.
Modern biotechnological techniques,such as the development of Genetically Modified $(GM)$ crops,pest-resistant plants (e.g.,$Bt$ cotton),and bio-fertilizers,have revolutionized food production.
These advancements have led to increased crop yields,reduced reliance on chemical pesticides,and improved nutritional quality of food,making agriculture the primary field for the maximum utilization of these techniques.

(A) $RNAi$ stands for $RNA$ interference.
$RNA$ interference is a biological process in which $RNA$ molecules inhibit gene expression or translation,by neutralizing targeted $mRNA$ molecules.
This method is used as a cellular defense mechanism against viruses and in the regulation of gene expression.
In biotechnology,it is used as a powerful tool to silence specific genes,such as in the case of protecting tobacco plants from the nematode $Meloidogyne$ $incognita$.

(A) Transgenic crops are genetically modified to express specific traits.
$Bt$ cotton is a well-known transgenic crop modified to develop resistance against insect pests (like bollworms) by expressing the $cry$ gene derived from the bacterium $Bacillus$ $thuringiensis$.
Tobacco plants have been genetically modified to develop resistance against the nematode $Meloidogyne$ $incognita$,which causes root-knot disease,using $RNA$ interference $(RNAi)$ technology.
Therefore,both tobacco and cotton are examples of transgenic crops modified for pest or insect resistance.

(D) The correct answer is $(d)$.
Genetic modification of crops has resulted in:
$(i)$ Increased tolerance against abiotic stresses (cold,drought,salt,and heat).
$(ii)$ Reduced reliance on chemical pesticides (pest-resistant crops).
$(iii)$ Reduced post-harvest losses.
$(iv)$ Enhanced nutritional value of food,$e.g.$,vitamin-$A$ enriched (golden rice).
$(v)$ Increased efficiency of mineral usage by plants (this prevents early exhaustion of soil fertility).
All these factors contribute to higher crop yields and better agricultural sustainability.

(A) Golden rice is a genetically modified variety of rice $(Oryza sativa)$ that has been engineered to produce beta-carotene, which is a precursor of Vitamin $A$.
Vitamin $A$ deficiency is a major cause of childhood blindness in developing and poor countries.
By consuming Golden rice, individuals can obtain the necessary Vitamin $A$ to prevent deficiency-related blindness.

(C) Hirudin is an anticoagulant protein originally found in the medicinal leech $(Hirudinaria)$.
It is now produced through genetic engineering using transgenic plants.
The gene encoding hirudin was transferred into $Brassica napus$ (rapeseed).
Hirudin accumulates in the seeds of these transgenic plants, from where it is extracted and purified for medicinal use.

(C) Prof. Anand Mohan Chakravorty developed a genetically engineered strain of bacteria capable of degrading hydrocarbons in oil spills. This 'Super bug' was created using species of the genus $Pseudomonas$ genus through recombinant $DNA$ technology.

(D) $Bt$ cotton is the first genetically modified plant that was commercially released in India. It was introduced to provide resistance against bollworm pests.

(A) Plants,bacteria,fungi,and animals whose genes have been altered by manipulation are known as Genetically Modified Organisms $(GMOs)$.
These organisms are created using recombinant $DNA$ technology to introduce specific traits.
The behavior and characteristics of a $GMO$ depend on the nature of the genes transferred and the specific host organism (plant,bacterium,or animal).

(A) $Dr. Anand Mohan Chakravorty$ introduced plasmids from different strains into a single cell of $Pseudomonas\ putida$.
The result was a new genetically engineered bacterium,which could degrade octane,hexane,decane,xylene,toluene,etc.
Hence,it is called a super bug (oil-eating bug).

(A) The Government of India established the $GEAC$ (Genetic Engineering Approval Committee) to regulate biotechnological activities.
This organization is responsible for making decisions regarding the validity of research involving $GM$ (Genetically Modified) organisms and the safety of introducing $GM$ organisms for public services.

(B) $RNA$ interference $(RNAi)$ is the correct answer.
$Meloidogyne$ $incognitia$ is a nematode that infects the roots of tobacco plants,leading to a significant reduction in yield.
To prevent this infection,a novel strategy based on the process of $RNA$ interference $(RNAi)$ was developed.
$RNAi$ involves the silencing of a specific $mRNA$ due to a complementary $dsRNA$ molecule that binds to and prevents translation of the $mRNA$ (silencing).
This process is a powerful tool in molecular biology for studying gene function and for developing pest-resistant crops.

(B) The nematode $Meloidogyne$ $incognita$ infects the roots of tobacco plants,which significantly reduces tobacco production. This infection can be prevented using the $RNA$ interference $(RNAi)$ process. In this process,the expression of a specific gene is silenced by a complementary $dsRNA$ molecule. The $dsRNA$ binds to the target $mRNA$ and prevents its translation,effectively silencing the gene.

(B) The production of value-added products such as nutritional supplements,pharmaceuticals,and biofuels using transgenic (genetically modified) crops is known as molecular farming. This process utilizes plants as biological factories to synthesize complex molecules for industrial or medical use.

(A) The primary objective of biotechnology in agriculture is to develop genetically modified crops that are resistant to pests and diseases. This reduces the dependency on chemical pesticides and increases crop yield. Examples include $Bt$ cotton and $Bt$ corn,which are engineered to express toxins that kill specific insect pests.

(B) Transgenic plants are plants that have been genetically modified by introducing foreign $DNA$ into their genome.
This process involves the insertion of a specific gene (transgene) from an unrelated organism into the plant cell,followed by the regeneration of a whole plant from that transformed cell using tissue culture techniques.
These plants are commonly referred to as genetically modified $(GM)$ crops.
Examples include $Bt$ cotton,golden rice,and Flavr Savr tomatoes.
Transgenic plants are developed for various purposes,such as pest resistance,improved nutritional content,and the production of industrial chemicals like fatty acids,sugars,and cellulose.