title: Transgenic expression of pectin methylesterase inhibitors limits tobamovirus spread in tobacco and Arabidopsis.
abstract: Plant infection by a virus is a complex process influenced by virus-encoded factors and host components which support replication and movement. Critical factors for a successful tobamovirus infection are the viral movement protein (MP) and the host pectin methylesterase (PME), an important plant counterpart that cooperates with MP to sustain viral spread. The activity of PME is modulated by endogenous protein inhibitors (pectin methylesterase inhibitors, PMEIs). PMEIs are targeted to the extracellular matrix and typically inhibit plant PMEs by forming a specific and stable stoichiometric 1:1 complex. PMEIs counteract the action of plant PMEs and therefore may affect plant susceptibility to virus. To test this hypothesis, we overexpressed genes encoding two well-characterized PMEIs in tobacco and Arabidopsis plants. Here, we report that, in tobacco plants constitutively expressing a PMEI from Actinidia chinensis (AcPMEI), systemic movement of Tobacco mosaic virus (TMV) is limited and viral symptoms are reduced. A delayed movement of Turnip vein clearing virus (TVCV) and a reduced susceptibility to the virus were also observed in Arabidopsis plants overexpressing AtPMEI-2. Our results provide evidence that PMEIs are able to limit tobamovirus movement and to reduce plant susceptibility to the virus.
authors.affiliation: Dipartimento di Biologia e Biotecnologie 'C. Darwin', 'Sapienza' Università di Roma, 00185, Roma, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Lionetti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Raiola
authors.forename: Felice
authors.initials: F
authors.lastname: Cervone
authors.forename: Daniela
authors.initials: D
authors.lastname: Bellincampi
mesh_terms: D029042:Actinidia / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000821:virology*; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D004951:Esterification; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000821:virology; D053830:Plant Viral Movement Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000502:physiology*; D017898:Tobamovirus / Q000502:physiology
chemical_list: D053830:Plant Viral Movement Proteins; D049452:Green Fluorescent Proteins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase