Nicotiana benthamiana resistance to non-adapted Melon necrotic spot virus results from an incompatible interaction between virus RNA and translation initiation factor 4E.
Nicotiana benthamiana has been described as non-host for Melon necrotic spot virus (MNSV). We investigated the basis of this resistance using the unique opportunity provided by strain MNSV-264, a recombinant virus that is able to overcome the resistance. Analysis of chimeric MNSV mutants showed that virulence in N. benthamiana is conferred by a 49 nucleotide section of the MNSV-264 3'-UTR, which acts in this host as a cap-independent translational enhancer (3'-CITE). Although the 3'-CITE of non-adapted MNSV-Mα5 is active in susceptible melon, it does not promote efficient translation in N. benthamiana, thus preventing expression of proteins required for virus replication. However, MNSV-Mα5 gains the ability to multiply in N. benthamiana cells if eIF4E from a susceptible melon variety (Cm-eIF4E-S) is supplied in trans. These data show that N. benthamiana resistance to MNSV-Mα5 results from incompatibility between the MNSV-Mα5 3'-CITE and N. benthamiana eIF4E in initiating efficient translation of the viral genome. Therefore, non-host resistance conferred by the inability of a host susceptibility factor to support viral multiplication may be a possible mechanism for this type of resistance to viruses.
Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), PO Box 164, 30100 Espinardo, Murcia, Spain.
Cristina
C
Nieto
Luis
L
Rodríguez-Moreno
Ana M
AM
Rodríguez-Hernández
Miguel A
MA
Aranda
Verónica
V
Truniger
D020413:3' Untranslated Regions / Q000235:genetics; D019184:Carmovirus / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics*; D016679:Genome, Viral; D007113:Immunity, Innate; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000821:virology*; D018515:Plant Leaves / Q000235:genetics / Q000821:virology; D014176:Protein Biosynthesis; D011523:Protoplasts / Q000821:virology; D012367:RNA, Viral / Q000235:genetics*; D011995:Recombination, Genetic; D014026:Nicotiana / Q000235:genetics / Q000821:virology*; D014774:Virulence; D014779:Virus Replication
D020413:3' Untranslated Regions; D039561:Eukaryotic Initiation Factor-4E; D012367:RNA, Viral