title: Properties of satellite tobacco mosaic virus phenotypes expressed in the presence and absence of helper virus.
abstract: In this study, we assembled an Agrobacterium-based transient expression system for the ectopic expression of Satellite tobacco mosaic virus (STMV) (+) or (-) transcripts and their biological activity was confirmed when Nicotiana benthamiana plants were co-expressed with helper Tobacco mosaic virus replicase. Characterization of STMV in the presence and absence of its HV revealed: (i) HV-dependent expression of STMV (+) in N. benthamiana, but not in N. tabacum, generated a replication-deficient but translation and encapsidation competent variant lacking the highly conserved 3' 150 nucleotides (nt) (STMVΔ150); (ii) mutational analysis demonstrated that a conserved 3' stem-loop structure in wild type and STMVΔ150 located between nt 874 and 897 is essential for translation of CP; (iii) helper virus-independent expression of CP from wt STMV was competent for the assembly of empty aberrant virion-like particles; whereas, CP translated from STMVΔ150 resulted in disorganized CP aggregates suggesting a role for the 3'tRNA-like structure in STMV assembly.
authors.affiliation: Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521, USA.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Sivanandam
authors.affiliation: Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Mathews
authors.affiliation: Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521, USA. Electronic address: arao@ucr.edu.
authors.forename: A L N
authors.initials: AL
authors.lastname: Rao
mesh_terms: D060054:Agrobacterium / Q000235:genetics; D015870:Gene Expression; D006378:Helper Viruses / Q000254:growth & development*; D010641:Phenotype; D014176:Protein Biosynthesis; D014026:Nicotiana / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000254:growth & development*; D019400:Tobacco mosaic satellite virus / Q000502:physiology*; D014170:Transformation, Genetic; D019065:Virus Assembly
keywords: Packaging; Replication; Satellite viruses; Translation; tRNA-like structure