How Are Crops Genetically Modified?

How Are Crops Genetically Modified?

• To modify crop plants, the gene must be able to gain access to the plant cell,which means it must be able to move through the plant’s rigid, outer cell wall.
• The “ferry” for moving genes into flowering plants is a naturally occurring plasmid of the bacterium Agrobacterium tumefaciens. In nature, this bacterium infects plants and causes tumors called galls
• The tumors are induced
• by a plasmid, called Ti plasmid. 
• Genes from different organisms can be inserted into the Ti plasmid by using 
• the same restriction enzyme to cut the Ti plasmid and the gene, and then connecting 
• the plasmid and the gene together and reinserting it into the bacterium.
• A. tumefaciens, with the recombinant Ti plasmid, is then used to infect plant 
• cells. During infection the recombinant plasmid is transferred into the host 
• plant cell.
• For genetic engineering purposes, scientists use only  the portion of a plasmid that does not cause tumor formation.
• Moving genes into other agricultural crops such as corn, barley, and rice can also be accomplished by using a device called a gene gun.
• A gene gun shoots tungsten-coated pellets covered with foreign DNA into plant cells.
• A small percentage of these DNA genes may be incorporated into the plant’s genome. The gene gun is often used by companies that do not want to pay licensing fees to Monsanto, holder of the A. tumefaciens patent.
• When a gene from one organism is incorporated into the genome of another organism, a transgenic organism is produced. Atransgenic organism is commonly referred to as a genetically modified organism or GMO.
• Many people have raised concerns about genetically modified (GM) crop plants. One concern is that large corporations that own many farms, called agribusiness corporations, profiting from GM crop production will put owners of family farms out of business. Other concerns focus on the impact of GMOs on human health and the environment.