Cell-to-cell movement of potato virus X: The role of p12 and p8 encoded by the second and third open reading frames of the triple gene block

• Published in: Molecular plant-microbe interactions Vol. 14; no. 10; pp. 1158 - 1167
• Main Authors: TAMAI, Atsushi, MESHI, Tetsuo
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01-10-2001; The American Phytopathological Society
• Subjects: Biolistics; Biological and medical sciences; Biological Transport; Capsid - genetics; Capsid - physiology; Cell Communication; Cell Membrane Permeability; CP protein; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Viral; green fluorescent protein; Green Fluorescent Proteins; Luminescent Proteins; Membrane Transport Proteins - physiology; Mutation; Nicotiana - genetics; Nicotiana - virology; Nicotiana benthamiana; Open Reading Frames - physiology; p12 protein; p25 protein; p8 protein; Pathology. Damages, economic importance; Phenotype; Phytopathology. Animal pests. Plant and forest protection; Plant viruses and viroids; Plants, Genetically Modified - cytology; Plants, Genetically Modified - virology; Potato virus X; Potexvirus - physiology; Ribonucleoproteins - physiology; Solanum tuberosum - cytology; Solanum tuberosum - virology; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - physiology; Intracellular movement; Cell permeability; Particle motion; Genetic variant; Viral protein; Biomembrane; Host virus relation; Structure function relationship; Virus; Gene; Potato virus Y; Dicotyledones; Angiospermae; Plasmodesm; Spermatophyta; Transgenic plant; Potyvirus; Solanaceae; Intraspecific comparison; Mutation; Experimental plant; Potyviridae
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi.2001.14.10.1158

Potato virus X (PVX) requires three proteins, p25, p12, and p8, encoded by the triple gene block plus the coat protein (CP) for cell-to-cell movement. When each of these proteins was co-expressed with a cytosolic green fluorescent protein (GFP) in the epidermal cells of Nicotiana benthamiana by the microprojectile bombardment-mediated gene delivery method, only p12 enhanced diffusion of co-expressed GFP, indicating an ability to alter plasmodesmal permeability. p25, p12, and CP, expressed transiently in the initially infected cells, transcomplemented the corresponding movement-defective mutants to spread through two or more cell boundaries. Thus, these proteins probably move from cell to cell with the genomic RNA. In contrast, p8 only functioned intracellularly and was not absolutely required for cell-to-cell movement. Since overexpression of p12 overcame the p8 deficiency, p8 appears to facilitate the functioning of p12, presumably by mediating its intracellular trafficking. Considering the likelihood that p12 and p8 are membrane proteins, it is suggested that intercellular as well as intracellular movement of PVX involves a membrane-mediated process.