title: A replicase of Potato virus X acts as the resistance-breaking determinant for JAX1-mediated resistance.
abstract: Lectin-mediated resistance (LMR) has been suggested to comprise an uncharacterized branch of antiviral plant innate immunity. To unveil the feature of resistance conferred by jacalin-type lectin required for potexvirus resistance 1 (JAX1), a recently isolated LMR gene against potexviruses, we analyzed the resistance-breaking variants to find the viral component involved in resistance. We employed grafting-mediated inoculation, a high-pressure virus inoculation method, to obtain Potato virus X (PVX) variants that can overcome JAX1-mediated resistance. Whole-genome sequencing of the variants suggested that a single amino acid in the methyl transferase domain of the replicase encoded by PVX is responsible for this resistance-breaking property. Reintroduction of the amino-acid substitution to avirulent wild-type PVX was sufficient to overcome the JAX1-mediated resistance. These results suggest that viral replicase is involved in JAX1-mediated resistance. The residue that determines the resistance-breaking properties was highly conserved among potexviruses, suggesting a general role of the residue in potexvirus-JAX1 interactions.
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sugawara
authors.forename: Takuya
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yoshida
authors.forename: Naoko
authors.initials: N
authors.lastname: Fujita
authors.forename: Osamu
authors.initials: O
authors.lastname: Netsu
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamaji
authors.forename: Shigetou
authors.initials: S
authors.lastname: Namba
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology / Q000821:virology*; D057865:Plant Immunity; D037121:Plant Lectins / Q000378:metabolism; D030821:Plants, Genetically Modified; D017863:Potexvirus / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D012367:RNA, Viral / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000276:immunology / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D037121:Plant Lectins; D012367:RNA, Viral; D014764:Viral Proteins; C043696:jacalin; D012324:RNA-Dependent RNA Polymerase