ABSTRACT
There has been tremendous progress in agricultural biotechnology in recent years. For example, transgenic plants resistant to insects, herbicides, and diseases have been produced, field-tested, and commercialized. In the case of viruses, significant breakthroughs opened new avenues to en-gineering resistance in crops. Resistance to viruses has been achieved by transforming susceptible plant varieties with genes or gene sequences derived from viral genomes. This approach is known as pathogen-derived resistance (PDR) (1). Advances continue to be made in understanding the cellular and molecular mechanisms of PDR, identifying effective virus-derived gene constructs, and developing virus-resistant transgenic crops.
