title: Genetic determinants of Potato virus Y required to overcome or trigger hypersensitive resistance to PVY strain group O controlled by the gene Ny in potato.
abstract: Potato virus Y (PVY) (genus Potyvirus) is the most economically damaging and widely distributed virus in potato. Spread of PVY in the field is controlled by growing resistant cultivars. The dominant potato gene Ny(tbr) for hypersensitive resistance (HR) controls ordinary PVY strains (PVY(O)) but is overcome by PVY(N) strains. Studies with infectious PVY chimeras and mutants indicated that the viral determinants necessary and sufficient to overcome Ny(tbr) reside within the helper component proteinase (HC-Pro) (residues 227 to 327). Specifically, eight residues and the modeled three-dimensional conformation of this HC-Pro region distinguish PVY(N) from PVY(O) strains. According to the model, the conserved IGN and CCCT motifs implicated in potyvirus replication and movement, respectively, are situated in a coiled structure and an α-helix, respectively, within this region in PVY(O); however, their locations are reversed in PVY(N). Two residues (R269 and K270) are crucial for the predicted PVY(O)-specific HC-Pro conformation. Two viral chimeras triggered Ny(tbr) and induced veinal necrosis in tobacco, which is novel for PVY. One chimera belonged to strain group PVY(E). Our results suggest a structure-function relationship in recognition of PVY(O) HC-Pro by Ny(tbr), reveal HC-Pro amino acid signatures specific to PVY(O) and PVY(N), and facilitate identification of PVY strains overcoming Ny(tbr).
authors.affiliation: Department of Agricultural Sciences, University of Helsinki, Finland.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Tian
authors.forename: Jari P T
authors.initials: JP
authors.lastname: Valkonen
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism; D002678:Chimera; D002874:Chromosome Mapping; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics* / Q000276:immunology; D005799:Genes, Dominant; D016679:Genome, Viral / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D017800:Potyvirus / Q000235:genetics* / Q000502:physiology; D017433:Protein Structure, Secondary; D017422:Sequence Analysis, DNA; D011198:Solanum tuberosum / Q000276:immunology* / Q000821:virology; D014026:Nicotiana / Q000276:immunology / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D010940:Plant Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus