title: Point mutations in the potato leafroll virus major capsid protein alter virion stability and aphid transmission.
abstract: The coat protein (CP) of potato leafroll virus (PLRV) is the primary component of the capsid, and is a multifunctional protein known to be involved in vector transmission and virus movement within plant hosts, in addition to particle assembly. Thirteen mutations were generated in various regions of the CP and tested for their ability to affect virus-host and virus-vector interactions. Nine of the mutations prevented the assembly of stable virions. These mutants were unable to infect systemically four different host species. Furthermore, although virus replication and translation of the CP were similar for the mutants and wild-type virus in individual plant cells, the translation of the CP readthrough product was affected in several of the mutants. Four of the mutants were able to assemble stable particles and infect host plants systemically, similarly to the wild-type virus; however, two of the mutants were transmitted less efficiently by aphid vectors. Based on a computer-generated model of the PLRV CP, the mutations that prevented virion assembly were associated with subunit interfaces, while the amino acid alterations in the assembly-competent mutants were associated with surface loops. This and previous work indicates that the CP structural model has value in predicting the structural architecture of the virion.
authors.affiliation: Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.|USDA/ARS, Plant Protection Research Unit, Ithaca, NY 14853, USA.
authors.forename: Igor B
authors.initials: IB
authors.lastname: Kaplan
authors.affiliation: Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.|USDA/ARS, Plant Protection Research Unit, Ithaca, NY 14853, USA.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Lee
authors.affiliation: Computational Biology Service Unit, Cornell Theory Center, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Ripoll
authors.affiliation: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Palukaitis
authors.affiliation: Department of Plant Pathology, Pennsylvania State University, University Park, PA, USA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Gildow
authors.affiliation: Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.|USDA/ARS, Plant Protection Research Unit, Ithaca, NY 14853, USA.
authors.forename: Stewart M
authors.initials: SM
authors.lastname: Gray
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000821:virology*; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics*; D052679:Luteoviridae / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000821:virology*; D017354:Point Mutation; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D014026:Nicotiana / Q000821:virology; D014771:Virion / Q000235:genetics / Q000502:physiology*; D019065:Virus Assembly / Q000235:genetics; D014779:Virus Replication / Q000235:genetics
chemical_list: D036022:Capsid Proteins