title: Single-chain antibodies against a plant viral RNA-dependent RNA polymerase confer virus resistance.
abstract: Crop loss due to viral diseases is still a major problem for agriculture today. We present a strategy to achieve virus resistance based on the expression of single-chain Fv fragments (scFvs) against a conserved domain in a plant viral RNA-dependent RNA polymerase (RdRp), a key enzyme in virus replication. The selected scFvs inhibited complementary RNA synthesis of different plant virus RdRps in vitro and virus replication in planta. Moreover, the scFvs also bound to the RdRp of the distantly related hepatitis C virus. T(1) and T(2) progeny of transgenic lines of Nicotiana benthamiana expressing different scFvs either in the cytosol or in the endoplasmic reticulum showed varying degrees of resistance against four plant viruses from different genera, three of which belong to the Tombusviridae family. Virus resistance based on antibodies to RdRps adds another tool to the repertoire for combating plant viruses.
authors.affiliation: Centrum Grüne Gentechnik, Dienstleistungszentrum Ländlicher Raum - Rheinpfalz-, Breitenweg 71, D-67435 Neustadt, Germany.
authors.forename: KaJohn
authors.initials: K
authors.lastname: Boonrod
authors.forename: Danuta
authors.initials: D
authors.lastname: Galetzka
authors.forename: Peter D
authors.initials: PD
authors.lastname: Nagy
authors.forename: Udo
authors.initials: U
authors.lastname: Conrad
authors.forename: Gabi
authors.initials: G
authors.lastname: Krczal
mesh_terms: D020816:Amino Acid Motifs / Q000276:immunology; D000914:Antibodies, Viral / Q000235:genetics / Q000494:pharmacology*; D010935:Plant Diseases / Q000821:virology*; D010942:Plant Viruses / Q000187:drug effects* / Q000201:enzymology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000037:antagonists & inhibitors* / Q000276:immunology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000821:virology; D017864:Tombusvirus / Q000187:drug effects / Q000201:enzymology / Q000472:pathogenicity; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000914:Antibodies, Viral; D012324:RNA-Dependent RNA Polymerase