Vaccines, Clones &Transgenics

 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

 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

 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

  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

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

  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

  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

  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

  X/bttoxin.htm  _pubs/biotech/insect.htm