title: The Nucleolar Fibrillarin Protein Is Required for Helper Virus-Independent Long-Distance Trafficking of a Subviral Satellite RNA in Plants.
abstract: RNA trafficking plays pivotal roles in regulating plant development, gene silencing, and adaptation to environmental stress. Satellite RNAs (satRNAs), parasites of viruses, depend on their helper viruses (HVs) for replication, encapsidation, and efficient spread. However, it remains largely unknown how satRNAs interact with viruses and the cellular machinery to undergo trafficking. Here, we show that the P20 protein of Bamboo mosaic potexvirus satRNA (satBaMV) can functionally complement in trans the systemic trafficking of P20-defective satBaMV in infected Nicotiana benthamiana The transgene-derived satBaMV, uncoupled from HV replication, was able to move autonomously across a graft union identified by RT-qPCR, RNA gel blot, and in situ RT-PCR analyses. Coimmunoprecipitation experiments revealed that the major nucleolar protein fibrillarin is coprecipitated in the P20 protein complex. Notably, silencing fibrillarin suppressed satBaMV-, but not HV-, phloem-based movement following grafting or coinoculation with HV Confocal microscopy revealed that the P20 protein colocalized with fibrillarin in the nucleoli and formed punctate structures associated with plasmodesmata. The mobile satBaMV RNA appears to exist as ribonucleoprotein (RNP) complex composed of P20 and fibrillarin, whereas BaMV movement proteins, capsid protein, and BaMV RNA are recruited with HV coinfection. Taken together, our findings provide insight into movement of satBaMV via the fibrillarin-satBaMV-P20 RNP complex in phloem-mediated systemic trafficking.
authors.affiliation: Institute of Plant Biology, National Taiwan University, Taipei 11106, Taiwan.|Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Chih-Hao
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Fu-Chen
authors.identifier: 0000-0003-1309-7596
authors.initials: FC
authors.lastname: Hsu
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Yih-Shan
authors.initials: YS
authors.lastname: Lo
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Jiun-Da
authors.initials: JD
authors.lastname: Wang
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Shaw
authors.affiliation: The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom.
authors.forename: Michael
authors.identifier: 0000-0002-6499-6439
authors.initials: M
authors.lastname: Taliansky
authors.affiliation: Department of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Ban-Yang
authors.initials: BY
authors.lastname: Chang
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Yau-Heiu
authors.identifier: 0000-0002-3071-4253
authors.initials: YH
authors.lastname: Hsu
authors.affiliation: Institute of Plant Biology, National Taiwan University, Taipei 11106, Taiwan nslin@sinica.edu.tw.|Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Na-Sheng
authors.identifier: 0000-0003-1148-6256
authors.initials: NS
authors.lastname: Lin
mesh_terms: D006378:Helper Viruses / Q000235:genetics*; D047468:Immunoprecipitation; D018749:RNA, Plant / Q000235:genetics*; D019244:RNA, Satellite / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012261:Ribonucleoproteins / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D018749:RNA, Plant; D019244:RNA, Satellite; D012261:Ribonucleoproteins; D014764:Viral Proteins