title: A single amino acid residue of RNA-dependent RNA polymerase in the Potato virus X genome determines the symptoms in Nicotiana plants.
abstract: A Potato virus X (PVX) strain, PVX-OS, causes a necrotic mosaic in Nicotiana benthamiana and ring spot mosaic in N. tabacum cv. SamsunNN. By contrast, strain PVX-BS causes a mild mosaic in N. benthamiana and systemic asymptomatic infection in N. tabacum cv. SamsunNN. To investigate the viral determinant of this difference, we produced various infectious cDNA clones chimeric between these PVX genomes and clones with point mutations introduced by site-directed mutagenesis. Inoculation tests with these clones mapped the symptom determinant in Nicotiana plants to the 1422 amino acid residue in the region of the C-terminus of RNA-dependent RNA polymerase (RdRp). Western blot analysis and local lesion assay indicated that virus accumulation in the infected leaves was similar for these PVX strains, suggesting that the symptom difference was not due to virus accumulation.
authors.affiliation: Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kagiwada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamaji
authors.forename: Ken
authors.initials: K
authors.lastname: Komatsu
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Takahashi
authors.forename: Takuma
authors.initials: T
authors.lastname: Mori
authors.forename: Hisae
authors.initials: H
authors.lastname: Hirata
authors.forename: Masashi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Masashi
authors.initials: M
authors.lastname: Ugaki
authors.forename: Shigetou
authors.initials: S
authors.lastname: Namba
mesh_terms: D019943:Amino Acid Substitution; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D017863:Potexvirus / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D012194:RNA-Directed DNA Polymerase / Q000235:genetics* / Q000502:physiology*; D011995:Recombination, Genetic; D014026:Nicotiana / Q000821:virology*; D014764:Viral Proteins / Q000032:analysis / Q000302:isolation & purification
chemical_list: D014764:Viral Proteins; D012194:RNA-Directed DNA Polymerase