title: A minimum length of N gene sequence in transgenic plants is required for RNA-mediated tospovirus resistance.
abstract: We showed previously that transgenic plants with the green fluorescent protein (GFP) gene fused to segments of the nucleocapsid (N) gene of tomato spotted wilt virus (TSWV) displayed post-transcriptional gene silencing of the GFP and N gene segments and resistance to TSWV. These results suggested that a chimeric transgene composed of viral gene segments might confer multiple virus resistance in transgenic plants. To test this hypothesis and to determine the minimum length of the N gene that could trans-inactivate the challenging TSWV, transgenic plants were developed that contained GFP fused with N gene segments of 24-453 bp. Progeny from these plants were challenged with: (i) a chimeric tobacco mosaic virus containing the GFP gene, (ii) a chimeric tobacco mosaic virus with GFP plus the N gene of TSWV and (iii) TSWV. A number of transgenic plants expressing the transgene with GFP fused to N gene segments from 110 to 453 bp in size were resistant to these viruses. Resistant plants exhibited post-transcriptional gene silencing. In contrast, all transgenic lines with transgenes consisting of GFP fused to N gene segments of 24 or 59 bp were susceptible to TSWV, even though the transgene was post-transcriptionally silenced. Thus, virus resistance and post-transcriptional gene silencing were uncoupled when the N gene segment was 59 bp or less. These results provide evidence that multiple virus resistance is possible through the simple strategy of linking viral gene segments to a silencer DNA such as GFP.
authors.affiliation: Department of Plant Pathology, Cornell University, NYSAES, Geneva, NY 14456, USA.
authors.forename: F J
authors.initials: FJ
authors.lastname: Jan
authors.forename: C
authors.initials: C
authors.lastname: Fagoaga
authors.forename: S Z
authors.initials: SZ
authors.lastname: Pang
authors.forename: D
authors.initials: D
authors.lastname: Gonsalves
mesh_terms: D015152:Blotting, Northern; D004797:Enzyme-Linked Immunosorbent Assay; D020868:Gene Silencing; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000821:virology*; D019251:Nucleocapsid / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000276:immunology / Q000821:virology*; D010947:Plants, Toxic; D012323:RNA Processing, Post-Transcriptional; D012367:RNA, Viral / Q000235:genetics / Q000502:physiology*; D014026:Nicotiana / Q000821:virology; D017865:Tospovirus / Q000235:genetics / Q000472:pathogenicity*; D014158:Transcription, Genetic; D019076:Transgenes
chemical_list: D008164:Luminescent Proteins; D012367:RNA, Viral; D049452:Green Fluorescent Proteins