Bt cotton, insect resistant plant

☺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 insecticidewhose gene has been derived from a
soil bacterium called Bacillus thuringiensis (Bt).
•Three types of toxins.
•A total of 229cry toxins ( cry1Aa to Cry72Aa), cyt
toxins ( cyt 11Aa to cyt3Aa) and 102 vip toxins(
vip1Aa1 to vip4Aa1) have been discovered.

4. 4
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
Shigetanein silkworm.
•Many Bt strains produce crystal proteins called
δ-endotoxinsduring 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 bollwormor old
world ( African) bollworm.
•Major pest of cotton.

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MODE OF ACTION OF Bt GENE
•Bacillus thuringiensisserves as an important
reservoir of crytoxins 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 Cry1Acwhich
is particularly specific to American Bollworm.

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•When insect ingest toxin crystals the alkaline
pHof 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 killingthe
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