Virus resistance

Viruses cause many plant diseases and are often responsible for extensive crop losses. This makes virus resistance an important goal for crop improvement.

Although chemicals can be used to manage most plant pest and diseases, there are no practical ways of eliminating plant viral infections. In some cases, pesticides can be use to manage insects that spread viruses. Virus resistant varieties of some plants have been developed by conventional breeding techniques.

Various strategies can be used to achieve virus resistance with the aid of genetic engineering:

• Viruses are enclosed by a protein coat composed of what are known as capsid proteins. If a plant is genetically transformed with a virus' capsid protein, it can be made resistant to the respective virus. All virus resistant plants commercially grown today are based on this concept.

• Other concepts target cell to cell virus movement or virus reproduction.

• Genes taken from plants that are known to produce antiviral proteins may be transferred to crops.