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Nemes K, Gil JF, Liebe S, Mansi M, Poimenopoulou E, Lennefors BL, Varrelmann M, Savenkov EI. Intermolecular base-pairing interactions, a unique topology and exoribonuclease-resistant noncoding RNAs drive formation of viral chimeric RNAs in plants. New Phytol 2024; 241:861-877. [PMID: 37897070 DOI: 10.1111/nph.19346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023]
Abstract
In plants, exoribonuclease-resistant RNAs (xrRNAs) are produced by many viruses. Whereas xrRNAs contribute to the pathogenicity of these viruses, the role of xrRNAs in the virus infectious cycle remains elusive. Here, we show that xrRNAs produced by a benyvirus (a multipartite RNA virus with four genomic segments) in plants are involved in the formation of monocistronic coat protein (CP)-encoding chimeric RNAs. Naturally occurring chimeric RNAs, we discovered, are composed of 5'-end of RNA 2 and 3'-end of either RNA 3 or RNA 4 bearing conservative exoribonuclease-resistant 'coremin' region. Using computational tools and site-directed mutagenesis, we show that de novo formation of chimeric RNAs requires intermolecular base-pairing interaction between 'coremin' and 3'-proximal part of the CP gene of RNA 2 as well as a stem-loop structure immediately adjacent to the CP gene. Moreover, knockdown of the expression of the XRN4 gene, encoding 5'→3' exoribonuclease, inhibits biogenesis of both xrRNAs and chimeric RNAs. Our findings suggest a novel mechanism involving a unique tropology of the intermolecular base-pairing complex between xrRNAs and RNA2 to promote formation of chimeric RNAs in plants. XrRNAs, essential for chimeric RNA biogenesis, are generated through the action of cytoplasmic Xrn 4 5'→3' exoribonuclease conserved in all plant species.
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Affiliation(s)
- Katalin Nemes
- Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, 75007, Sweden
| | - Jose F Gil
- Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, 75007, Sweden
- VEDAS Corporación de Investigación e Innovación (VEDAS CII), Medellín, 050024, Colombia
| | - Sebastian Liebe
- Department of Phytopathology, Institute of Sugar Beet Research, Göttingen, 37079, Germany
| | - Mansi Mansi
- Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, 75007, Sweden
| | - Efstratia Poimenopoulou
- Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, 75007, Sweden
| | | | - Mark Varrelmann
- Department of Phytopathology, Institute of Sugar Beet Research, Göttingen, 37079, Germany
| | - Eugene I Savenkov
- Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, 75007, Sweden
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