title: P1/HC-Pro, a viral suppressor of RNA silencing, interferes with Arabidopsis development and miRNA unction.
abstract: The molecular basis for virus-induced disease in plants has been a long-standing mystery. Infection of Arabidopsis by Turnip mosaic virus (TuMV) induces a number of developmental defects in vegetative and reproductive organs. We found that these defects, many of which resemble those in miRNA-deficient dicer-like1 (dcl1) mutants, were due to the TuMV-encoded RNA-silencing suppressor, P1/HC-Pro. Suppression of RNA silencing is a counterdefensive mechanism that enables systemic infection by TuMV. The suppressor interfered with the activity of miR171 (also known as miRNA39), which directs cleavage of several mRNAs coding for Scarecrow-like transcription factors, by inhibiting miR171-guided nucleolytic function. Out of ten other mRNAs that were validated as miRNA-guided cleavage targets, eight accumulated to elevated levels in the presence of P1/HC-Pro. The basis for TuMV- and other virus-induced disease in plants may be explained, at least partly, by interference with miRNA-controlled developmental pathways that share components with the antiviral RNA-silencing pathway.
authors.affiliation: Center for Gene Research and Biotechnology and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Kristin D
authors.initials: KD
authors.lastname: Kasschau
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Xie
authors.forename: Edwards
authors.initials: E
authors.lastname: Allen
authors.forename: Cesar
authors.initials: C
authors.lastname: Llave
authors.forename: Elisabeth J
authors.initials: EJ
authors.lastname: Chapman
authors.forename: Kate A
authors.initials: KA
authors.lastname: Krizan
authors.forename: James C
authors.initials: JC
authors.lastname: Carrington
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D015152:Blotting, Northern; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D015151:Immunoblotting; D035683:MicroRNAs / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D008859:Microscopy, Polarization; D016297:Mutagenesis, Site-Directed; D018514:Plant Structures / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D030821:Plants, Genetically Modified; D010957:Plasmids; D016133:Polymerase Chain Reaction; D034622:RNA Interference / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017806:Tymovirus / Q000472:pathogenicity*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; D035683:MicroRNAs; D012333:RNA, Messenger; D018749:RNA, Plant; C100978:SCR protein, Arabidopsis; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus