☺INTRODUCTION ☺Bt COTTON ☺MAJOR PESTS OF COTTON ☺MODE OF ACTION OF Bt GENE ☺ADVANTAGES ☺DISADVANTAGES ☺CONCLUSION ☺REFERENCES Genetically modified variety of cotton that produces an insecticide whose gene has been derived from a soil bacterium called Bacillus thuringiensis (Bt). Three types of toxins. A total of 229 cry toxins ( cry1Aa to Cry72Aa), cyt toxins ( cyt 11Aa to cyt3Aa) and 102 vip toxins( vip1Aa1 to vip4Aa1) have been discovered.

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Bt COTTON
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

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CONTENTS
☺INTRODUCTION
☺Bt COTTON
☺MAJOR PESTS OF COTTON
☺MODE OF ACTION OF Bt GENE
☺ADVANTAGES
☺DISADVANTAGES
☺CONCLUSION
☺REFERENCES

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WHAT IS Bt COTTON?
• Genetically modified variety of cotton that produces
an insecticide whose gene has been derived from a
soil bacterium called Bacillus thuringiensis (Bt).
• Three types of toxins.
• A total of 229 cry toxins ( cry1Aa to Cry72Aa), cyt
toxins ( cyt 11Aa to cyt3Aa) and 102 vip toxins(
vip1Aa1 to vip4Aa1) have been discovered.

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Insecticidal
toxin
crystal
(cry) toxins
cytolytic
(cyt) toxins
Vegetatively
expressed
insecicidal
proteins
(vip)

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Bacillus thuringiensis
• Gram positive soil bacterium.
• Commonly used as a biological pesticide.
• It was discovered in 1901 by Ishiwatori
Shigetane in silkworm.
• Many Bt strains produce crystal proteins called
δ-endotoxins during sporulation, that have
insecticidal action.This has led to their use as
insecticides.

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• Cotton was one of the first crop to be genetically
engineered by the US based agrochemical
multinational MONSANTO(transgenic bollgard Bt
cottonseed.
• Imported in India by Mahyco( Maharashtra hybrid
seed company from MONSANTO.

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Pectinophora gossypiella
• Commonly known as PINK BOLLWORM
• The pink bollworm withdraws nutrients from
the cottonseed and may cause serious yield
losses.

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Anthonomos grandis
• Commonly known as Boll weevil.
• It is a beetle which feeds on cotton buds and
flowers.

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Earias insulana
■ Commonly known as spotted bollworm.
■ It feed on the developing cotton bolls, poses threat to cotton
yields all over.

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Helicoverpa armigera
• Commonly known as cotton bollworm or old
world ( African) bollworm.
• Major pest of cotton.

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MODE OF ACTION OF Bt GENE
• Bacillus thuringiensis serves as an important
reservoir of cry toxins and cry genes for production
of biological insecticides and insect-resistant
genetically modified crops.
• The Bt gene was isolated and transferred from
bacteria to American cotton to produce Bt cotton.
• This cotton variety produces Bt toxin Cry1Ac which
is particularly specific to American Bollworm.

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• When insect ingest toxin crystals the alkaline
pH of their digestive tract cause the toxin to
become activated.
• It becomes inserted into the insect’s gut cell
membranes forming a pore resulting in
swelling,cell lysis and eventually killing the
insect.

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DEVELOPMENT OF Bt COTTON

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Bt cotton hybrids available in India
MONSANTO Cry 1Ac and Cry 1Ac+Cry
2Ab
CHINESE ACADEMY
OF AGRICULTURAL
SCIENCES THROUGH
NATH SEEDS
Cry 1Ac
METAHELIX Modified Cry 1Ac
JK SEED Cry 1Ac

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ADVANTAGES OF Bt COTTON

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DISADVANTAGES

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CONCLUSION

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REFERENCES
www.cicr.org.in/pdf/transgenic_bt_cotton.pdf