title: Sumoylation ofTurnip mosaic virusRNA Polymerase Promotes Viral Infection by Counteracting the Host NPR1-Mediated Immune Response.
abstract: Sumoylation is a transient, reversible dynamic posttranslational modification that regulates diverse cellular processes including plant-pathogen interactions. Sumoylation of NPR1, a master regulator of basal and systemic acquired resistance to a broad spectrum of plant pathogens, activates the defense response. Here, we report that NIb, the only RNA-dependent RNA polymerase ofTurnip mosaic virus(TuMV) that targets the nucleus upon translation, interacts exclusively with and is sumoylated by SUMO3 (SMALL UBIQUITIN-LIKE MODIFIER3), but not the three otherArabidopsis thalianaSUMO paralogs. TuMV infection upregulates SUMO3 expression, and the sumoylation of NIb by SUMO3 regulates the nuclear-cytoplasmic partitioning of NIb. We identified the SUMO-interacting motif in NIb that is essential for its sumoylation and found that knockout or overexpression of SUMO3 suppresses TuMV replication and attenuates viral symptoms, suggesting that SUMO3 plays dual roles as a host factor of TuMV and as an antiviral defender. Sumoylation of NIb by SUMO3 is crucial for its role in suppressing the host immune response. Taken together, our findings reveal that sumoylation of NIb promotes TuMV infection by retargeting NIb from the nucleus to the cytoplasm where viral replication takes place and by suppressing host antiviral responses through counteracting the TuMV infection-induced, SUMO3-activated, NPR1-mediated resistance pathway.
authors.affiliation: London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cheng
authors.affiliation: London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada.|Department of Biology, Western University, London, Ontario N6A 5B7, Canada.
authors.forename: Ruyi
authors.initials: R
authors.lastname: Xiong
authors.affiliation: London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada.|Department of Biology, Western University, London, Ontario N6A 5B7, Canada.
authors.forename: Yinzi
authors.initials: Y
authors.lastname: Li
authors.affiliation: London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Xueping
authors.initials: X
authors.lastname: Zhou
authors.affiliation: London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada aiming.wang@agr.gc.ca.|Department of Biology, Western University, London, Ontario N6A 5B7, Canada.
authors.forename: Aiming
authors.initials: A
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000821:virology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology; D017800:Potyvirus / Q000201:enzymology / Q000472:pathogenicity; D011499:Protein Processing, Post-Translational / Q000235:genetics / Q000502:physiology; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism; D058207:Sumoylation; D017806:Tymovirus / Q000201:enzymology / Q000472:pathogenicity; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C105496:NPR1 protein, Arabidopsis; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase; C061396:nuclear inclusion protein b, mosaic viruses; D012321:DNA-Directed RNA Polymerases