Like animals, plants, especially, high yielding crop plants are infected by several pests and disease causing organisms. Pests are animals, especially insects which cause a great deal of damage to economically important plants.
The disease causing organisms are called pathogenic organisms. Among these are many fungi, bacteria and viruses. Some plants do possess inherent disease resistance mechanisms, while others do not.
Lack of disease resistance causes a great deal of damage to economically important plants and consequently, decrease productivity.
Genetic engineering has a’ potential promise in creating disease resistant transgenic plants by transferring such genes conferring resistance to pathogenic organisms to economically important plants. In the following sections, the application of genetic engineering in raising disease resistant plant varieties to bacteria, fungi and viruses is discussed.