title: Temperature-dependent symptom recovery in Nicotiana benthamiana plants infected with tomato ringspot virus is associated with reduced translation of viral RNA2 and requires ARGONAUTE 1.
abstract: Symptom recovery in nepovirus-infected plants has been attributed to the induction of RNA silencing. However, recovery is not always accompanied with viral RNA clearance. In this study, we show that recovery of Nicotiana benthamiana plants infected with the tomato ringspot virus (ToRSV) is associated with a reduction of the steady-state levels of RNA2-encoded coat protein (CP) and movement protein but not of RNA2. In vivo labeling experiments revealed efficient synthesis of the CP early in infection, but reduced RNA2 translation later in infection. Silencing of Argonaute1-like (Ago1) genes prevented both symptom recovery and RNA2 translation repression. Similarly, growing the plants at lower temperature (21 °C rather than 27 °C) alleviated the recovery and the translation repression. Taken together, our results suggest that recovery of ToRSV-infected plants is associated with an Ago1-dependent mechanism that represses the translation of viral RNA2.
authors.affiliation: Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.
authors.forename: Basudev
authors.initials: B
authors.lastname: Ghoshal
authors.affiliation: Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4; Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, PO Box 5000, 4200 Highway 97, Summerland, BC, Canada V0H 1Z0. Electronic address: helene.sanfacon@agr.gc.ca.
authors.forename: Hélène
authors.initials: H
authors.lastname: Sanfaçon
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D017860:Nepovirus / Q000502:physiology*; D010935:Plant Diseases / Q000276:immunology / Q000821:virology*; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000235:genetics*; D013696:Temperature; D014026:Nicotiana / Q000276:immunology / Q000528:radiation effects / Q000821:virology*
chemical_list: D060565:Argonaute Proteins; D012367:RNA, Viral
keywords: Antiviral response; Nepovirus; Plant–virus interactions; RNA silencing