title: Antiviral Defense Involves AGO4 in an Arabidopsis-Potexvirus Interaction.
abstract: In plants, RNA silencing regulates gene expression through the action of Dicer-like (DCL) and Argonaute (AGO) proteins via micro RNAs and RNA-dependent DNA methylation (RdDM). In addition, RNA silencing functions as an antiviral defense mechanism by targeting virus-derived double-stranded RNA. Plants encode multiple AGO proteins with specialized functions, including AGO4-like proteins that affect RdDM and AGO2, AGO5, and AGO1, which have antiviral activities. Here, we show that AGO4 is also required for defense against the potexvirus Plantago asiatica mosaic virus (PlAMV), most likely independent of RdDM components such as DCL3, Pol IV, and Pol V. Transient assays showed that AGO4 has direct antiviral activity on PlAMV and, unlike RdDM, this activity does not require nuclear localization of AGO4. Furthermore, although PlAMV infection causes a decrease in AGO4 expression, PlAMV causes a change in AGO4 localization from a largely nuclear to a largely cytoplasmic distribution. These results indicate an important role for AGO4 in targeting plant RNA viruses as well as demonstrating novel mechanisms of regulation of and by AGO4, independent of its canonical role in regulating gene expression by RdDM.
authors.affiliation: 1 Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
authors.forename: Chantal
authors.initials: C
authors.lastname: Brosseau
authors.affiliation: 1 Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.|2 Current address: Department of Biology, PYD, King Faisal University, Al Hasa, Kingdom of Saudi Arabia; and.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Oirdi
authors.affiliation: 1 Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
authors.forename: Ayooluwa
authors.initials: A
authors.lastname: Adurogbangba
authors.affiliation: 1 Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.|3 College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Ma
authors.affiliation: 1 Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Moffett
mesh_terms: D000998:Antiviral Agents / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000821:virology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology; D017863:Potexvirus / Q000502:physiology*; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000821:virology
chemical_list: C471209:AGO4 protein, Arabidopsis; D000998:Antiviral Agents; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins