Chapter 6 Plant Biotechnology (contd.)

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Chapter 6Plant Biotechnology (contd.)

• Vaccines, Clones Transgenics

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What are plant vaccines?

• Plant vaccines contain dead or weakened strains
  of plant virus which are injected to plants
  against diseases
• Vaccines can also be encoded in plant DNA
• Transgenic plants can synthesize protein antigens
  that retain immunological properties

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What are plant vaccines?

• The Tobacco Mosaic virus (TMV), produces a
  protein on surface of the virus which turns on
  the plant immune system in tobacco plants
• Tobacco plants with TMV has the resistance
  against the virus

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Plants as surrogates to produce antigens

• With the advent of modern molecular biology
  techniques in the 1980s, new strategies were
  developed for the production of subunit vaccines
• Green plants are used as the surrogate
  production organism to produce antigens of human
  pathogens

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Five antigens expressed in plants and useful to
animals and man

• Rabies virus G-protein in tomato
• Norwalk virus Capsid protein in tobacco potato
• Hepatitus B virus surface antigen in tobacco
  potato
• E.coli heat-labile enterotoxin B subunit (LT-B)
  in tobacco potato
• Cholera toxin B subunit (CT-B) in potato

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Banana is a likely delivery plant

• Eaten raw
• Appealing to children
• Inexpensive to produce
• Native to many developing countries
• Still under clinical trials

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Genetic pesticides

• The BT gene in Bacillus thuringiensis , produces
  a crystalline protein that kills insects and
  their larvae (an insecticidal protein).
• Instead of spreading the bacteria in the field
  now can spread Bt genes!!! Tomatoes, potatoes,
  corn , cotton etc.
• Today, plants can be genetically engineered to
  produce their own Bt

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Genetic herbicides

• Crops are genetically engineered to be resistant
  to common herbicide called glyphosate( an enzyme
  which block photosynthesis)
• Generally herbicides are used to kill weeds and
  by doing so, crops get affected.
• Hence the need for genetically engineered
  herbicide resistant crops

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Golden Rice

• Deficiency of Vitamin A causes night blindness.
• Genetically engineered rice to produce large
  amount of Beta carotene, a provitamin which body
  converts to Vitamin A.
• Read pg 144 test book for further info

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Reference

• http//www.nal.usda.gov/bic/BTTOX/bttoxin.htm
• http//www.ag.uiuc.edu/vista/html_pubs/biotech/in
  sect.htm