Genes that confer viral pathogen-derived resistance (PDR) include thos
e for coat proteins, replicases, movement proteins, defective interfer
ing RNAs and DNAs, and nontranslated RNAs. In addition to developing d
isease-resistant plant varieties for agriculture, PDR has increased th
e understanding of viral pathogenesis and disease. Furthermore, signif
icant advances in elucidating the fundamental principles underlying re
sistance will lead to second and third generation genes that confer in
creased levels of sustainable resistance.