2. What is Genetically modified crop?
• Genetically modified crops (GM crops) are plants used in agriculture, the DNA of which has been
modified using genetic engineering methods.
• Plant genomes can be engineered by physical methods or by use of Agrobacterium for the delivery of
sequences hosted in T-DNA binary vectors.
• The aim is to introduce a new trait to the plant which does not occur naturally in the species.
• Examples in food crops include resistance to certain pests, diseases, environmental conditions,
reduction of spoilage, resistance to chemical treatments (e.g. resistance to a herbicide), or improving
the nutrient profile of the crop.
3. Bt Crops:
• Bacillus thuringiensis (Bt) is a Gram-positive, spore forming, soil bacterium.
• Bt crops are transgenic crops that are genetically engineered from the DNA of
bacterium Bacillus thuringiensis
• When resources are limited, vegetative Bt cells undergo sporulation.
• A protein crystal, the insecticidal crystal proteins (ICPs) or Cry Proteins.
• These Cry proteins are coded by genes (cry genes).
4. • For over 50 years, Bt has been applied to crops in spray form as an
insecticide, containing a mixture of spores and the associated protein
crystals.
• When an insect feeds on the transgenic plants, the toxic cry protein
present in the plants crystallizes the digestive system of insects
• This leads to death of insect. However, it has no harmful effects on the
human digestive system.
5. Types of Bt crops
1. Bt Cotton :
The Bt cotton variety is genetically transformed with the Bt gene to protect the
plants from bollworm, a major pest of cotton.
The worms present on the leaves of Bt cotton become lethargic and sleepy and
thus, cause less damage to the plants.
When the worms consume the plant, the toxic proteins produced by the crops are
ingested, thereby, killing them.
6. Bt Brinjal
• Bt brinjal is also produced by genetic transformation of a crystal protein gene cry 1 Ac from the
bacterium Bacillus thuringiensis.
• Bt brinjal was developed to provide resistance against lepidopteron insects.
• The proteins produced by Bt genes bind to the receptors present on the insect’s membrane,
resulting in the formation of pores on the membranes.
• This disrupts the digestive process and leads to the death of the insect.
7. • Advantages of Bt Crop:
• It helps in improving the crop yield, thereby, raising the farmer’s income.
• Bt crops help in protecting beneficial insects.
• It leads to the production of disease-free crops owing to the reduction of pesticides.
• It leads to more productivity in a small area of land.
• Disadvantages of Bt Crops
• Bt crops have a few disadvantages as well:
• Bt crops are costlier than naturally grown crops.
• It can disrupt the natural process of gene flow.
• The pests might become resistant to the toxins produced by these crops and the crop production might decline.
8. Golden rice
• Golden rice is a variety of rice (Oryza sativa) produced through
genetic engineering to biosynthesize beta-carotene, a precursor
of vitamin A, in the edible parts of rice.
• Produces a Bio fortified food.(The creation of plants that make
or accumulate micronutrients)
• Consumed in areas with a shortage of dietary vitamin A, a
deficiency which each year is estimated to kill 670,000 children
under the age of 5.
• Golden rice differs from its parental strain by the addition of three
beta-carotene biosynthesis genes.
9. EFFECTS OF MALNUTRITION
• Symptoms of vitamin A deficiency (VAD) include; night blindness, increased susceptibility to
infection and cancer, anemia (lack of red blood cells or hemoglobin), deterioration of the eye
tissue, and cardiovascular disease.
• Nearly 9 million children die from malnutrition each year. A large proportion of those children
die from common illnesses that could have been avoided through adequate nutrition
10. GOALS
• Mutate rice plants to produce carotenoids, or organic pigments, specifically β-
carotene (pro-vitamin A) in the endosperm, the edible part of the grain.
• Make Golden Rice accessible locally, free of charge to farmers, who are able to
grow, save, consume, replant and locally sell Golden Rice.
11. • Golden rice was created by transforming rice with only two β-carotene
biosynthesis genes:
• 1). psy (Phytoene synthase) from daffodil (Narcissus pseudonarcissus)
• 2). crtI (Carotene desaturase) from the soil bacterium Erwinia uredovora
12.
13. Flavr Savr Tomato
• A genetically modified tomato, or transgenic tomato is a tomato that has had its genes
modified.
• The first commercially available genetically modified food was a tomato engineered to have a
longer shelf life (FLAVR SAVR).
• Produced by Californian company Calgene 1992.
• Calgene introduced a gene in plant which synthesize a complementary mRNA to PG gene and
inhibiting the synthesis of PG enzyme.
• On May 21, 1994, the genetically engineered Flavr Savr tomato was introduced.
14.
15. • Softening of fruits is largely due to degradation of cell wall (pectin) by enzyme
polygalacturonase (PG).
• The gene encoding PG has been isolated and cloned .
• Procedure involves: -
• 1) Isolation of DNA from tomato plant that encodes the enzyme polygalacturonase (PG).
• 2) Transfer of PG gene to a vector bacteria and production of complementary DNA
(cDNA) molecules.
• 3) Introduction of cDNA into a fresh tomato plant to produce transgenic plant
16. • In normal plants, PG gene encodes a normal or sense mRNA that produce the enzyme
PG and it is actively involved in fruit ripening.
• The cDNA of PG encodes for antisense mRNA, which is complementary to sense
mRNA.
• The hybridization between sense and antisense mRNA render the sense mRNA
ineffective.
• Consequently, no polygalacturonase is produced hence fruit ripening is delayed
19. EDIBLE VACCINE
• A protein which acts as the vaccine, present in food and consumed as the internal composition of
food is known as EDIBLE VACCINE.
• EDIBLE VACCINE- WHY?
• Edible vaccine gives cost-effective, easy-to-administer.
• Needle free- Oral vaccines provide “mucosal immunity” at various sites by secreting antibodies.
• Low risk of infection.
• Storage-• Heat-stable
• Safe
20. • The goal of oral vaccination is to stimulate the mucosal and systemic immunity against
pathogen.
• Development of edible vaccines involves the process of incorporating the selected desired genes
into plants and then enabling these altered plants to produce the encoded proteins.
• This process is known as transformation, and the altered plants are known as transgenic plants
