title: A coat-independent superinfection exclusion rapidly imposed in Nicotiana benthamiana cells by tobacco mosaic virus is not prevented by depletion of the movement protein.
abstract: New evidence is emerging which indicates that population variants in plant virus infections are not uniformly distributed along the plant, but structured in a mosaic-like pattern due to limitation to the superinfection imposed by resident viral clones. The mechanisms that prevent the infection of a challenge virus into a previously infected cell, a phenomenon known as superinfection exclusion (SE) or Homologous Interference, are only partially understood. By taking advantage of a deconstructed tobacco mosaic virus (TMV) system, where the capsid protein (CP) gene is replaced by fluorescent proteins, an exclusion mechanism independent of CP was unveiled. Time-course superinfection experiments provided insights into SE dynamics. Initial infection levels affecting less than 10 % of cells led to full immunization in only 48 h, and measurable immunization levels were detected as early as 6 h post-primary infection. Depletion of a functional movement protein (MP) was also seen to slow down, but not to prevent, the SE mechanism. These observations suggest a CP-independent mechanism based on competition for a host-limiting factor, which operates at very low virus concentration. The possible involvement of host factors in SE has interesting implications as it would enable the host to influence the process.
authors: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC), Universidad Politécnica de Valencia, Avda Tarongers SN, 46022, Valencia, Spain.
authors: José Manuel
authors: JM
authors: Julve
authors: Antoni
authors: A
authors: Gandía
authors: Asun
authors: A
authors: Fernández-Del-Carmen
authors: Alejandro
authors: A
authors: Sarrion-Perdigones
authors: Bas
authors: B
authors: Castelijns
authors: Antonio
authors: A
authors: Granell
authors: Diego
authors: D
authors: Orzaez
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005814:Genes, Viral; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D059828:Plant Cells; D010935:Plant Diseases / Q000276:immunology / Q000821:virology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000821:virology; D021381:Protein Transport; D013997:Time Factors; D014026:Nicotiana / Q000235:genetics / Q000276:immunology / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D014762:Viral Interference; D000097573:Red Fluorescent Protein
chemical_list: D036022:Capsid Proteins; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein