Control of Plant Virus Diseases by Pathogen-Derived Resistance in Transgenic Plants

Plant viruses have an enormous negative impact on agri- cultural crop production throughout the world, and, conse- quently, agronomists and plant pathologists have devoted considerable effort toward controlling virus diseases during this century. Prior to the advent of genetic engineering, traditional plant breeding methodology was sometimes suc- cessfully applied to develop resistance to viruses of agron- omically important crops. In addition, standard techniques of plant pathology, including quarantine, eradication, crop ro- tation, and certified virus-free stock, have been important tools to control virus diseases, although each has disadvan- tages, such as expense, questionable effectiveness, and lack