Insecticidal property of cry proteins
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Bacillus thuringiensis (Bt) is a gram-positive bacterium, generally used as biological pesticide.
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During sporulation many Bt strains produce endotoxins that are in crystal form, called as “cry proteins”.
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Cry proteins are encoded by cry genes which are located on a plasmid.
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If these crystal proteins been ingested by the larvae, they become soluble and cleaved to protease that is in gut. This produce the active toxin called delta-endotoxin.
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This describes insecticidal and pesticidal property of Cry proteins.
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By using these endotoxin genes of cry protein, genetically modified crops were created called as “Bt crops”. Examples: Bt cotton, Bt potato, Bt Soybean, Bt corn.