A single amino acid residue of RNA-dependent RNA polymerase in the Potato virus X genome determines the symptoms in Nicotiana plants.
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.
Kagiwada
Satoshi
S
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.
Yamaji
Yasuyuki
Y
Komatsu
Ken
K
Takahashi
Shuichiro
S
Mori
Takuma
T
Hirata
Hisae
H
Suzuki
Masashi
M
Ugaki
Masashi
M
Namba
Shigetou
S
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
D014764:Viral Proteins; D012194:RNA-Directed DNA Polymerase