title: Homeologs of the Nicotiana benthamiana Antiviral ARGONAUTE1 Show Different Susceptibilities to microRNA168-Mediated Control.
abstract: The plant ARGONAUTE1 protein (AGO1) is a central functional component of the posttranscriptional regulation of gene expression and the RNA silencing-based antiviral defense. By genomic and molecular approaches, we here reveal the presence of two homeologs of the AGO1-like gene in Nicotiana benthamiana, NbAGO1-1H and NbAGO1-1L. Both homeologs retain the capacity to transcribe messenger RNAs (mRNAs), which mainly differ in one 18-nucleotide insertion/deletion (indel). The indel does not modify the frame of the open reading frame, and it is located eight nucleotides upstream of the target site of a microRNA, miR168, which is an important modulator of AGO1 expression. We demonstrate that there is a differential accumulation of the two NbAGO1-1 homeolog mRNAs at conditions where miR168 is up-regulated, such as during a tombusvirus infection. The data reported suggest that the indel affects the miR168-guided regulation of NbAGO1 mRNA. The two AGO1 homeologs show full functionality in reconstituted, catalytically active RNA-induced silencing complexes following the incorporation of small interfering RNAs. Virus-induced gene silencing experiments suggest a specific involvement of the NbAGO1 homeologs in symptom development. The results provide an example of the diversity of microRNA target regions in NbAGO1 homeolog genes, which has important implications for improving resilience measures of the plant during viral infections.
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.).
authors.forename: Torsten
authors.initials: T
authors.lastname: Gursinsky
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.).
authors.forename: Walter
authors.identifier: http://orcid.org/0000-0002-2717-4735
authors.initials: W
authors.lastname: Pirovano
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.).
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gambino
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.).
authors.forename: Susann
authors.initials: S
authors.lastname: Friedrich
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.).
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Behrens
authors.affiliation: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany (T.G., S.F., S.-E.B.);BaseClear, 233CC Leiden, The Netherlands (W.P.);Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Grugliasco, 10135 Turin, Italy (G.G.); and Institute for Sustainable Plant Protection-Consiglio Nazionale delle Ricerche, Research Unit of Bari, 70126 Bari, Italy (V.P.) vitantonio.pantaleo@cnr.it.
authors.forename: Vitantonio
authors.identifier: http://orcid.org/0000-0001-6677-6504
authors.initials: V
authors.lastname: Pantaleo
mesh_terms: D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000378:metabolism; D060565:Argonaute Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D055162:Biocatalysis; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant; D017930:Genes, Reporter; D056426:Genetic Loci; D014644:Genetic Variation; D018745:Genome, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D054643:INDEL Mutation / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D017864:Tombusvirus / Q000502:physiology
chemical_list: D000998:Antiviral Agents; D060565:Argonaute Proteins; D035683:MicroRNAs; D010940:Plant Proteins; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins