title: Sequence characterization, molecular phylogeny reconstruction and recombination analysis of the large RNA of Tomato spotted wilt virus (Tospovirus: Bunyaviridae) from the United States.
abstract: BACKGROUND
  Tomato spotted wilt virus (TSWV; Tospovirus: Bunyaviridae) has been an economically important virus in the USA for over 30 years. However the complete sequence of only one TSWV isolate PA01 characterized from pepper in Pennsylvania is available.
  
  
  RESULTS
  The large (L) RNA of a TSWV WA-USA isolate was cloned and sequenced. It consisted of 8914 nucleotides (nt) encoding a single open reading frame of 8640 nts in the viral-complementary sense. The ORF potentially codes for RNA-dependent RNA polymerase (RdRp) of 330.9 kDa. Two untranslated regions of 241 and 33 nucleotides were present at the 5' and 3' termini, respectively that shared conserved tospoviral sequences. Phylogenetic analysis using nucleotide sequences of the complete L RNA showed that TSWV WA-USA isolate clustered with the American and Asian TSWV isolates which formed a distinct clade from Euro-Asiatic Tospoviruses. Phylogeny of the amino acid sequence of all tospoviral RdRps used in this study showed that all the known TSWV isolates including the USA isolate described in this study formed a distinct and a close cluster with that of Impateins necrotic spot virus. Multiple sequence alignment revealed conserved motifs in the RdRp of TSWV. Recombination analysis identified two recombinants including the TSWV WA-USA isolate. Among them, three recombination events were detected in the conserved motifs of the RdRp.
  
  
  CONCLUSIONS
  Sequence analysis and phylogenetic analysis of the L RNA showed distinct clustering with selected TSWV isolates reported from elsewhere. Conserved motifs in the core polymerase region of the RdRp and recombination events were identified.
authors.affiliation: Department of Plant Pathology, Washington State University, 123 Vogel Plant BiologicalSciences, Pullman, WA, 99164, USA.|ICAR-Directorate of Soybean Research, Khandwa Road, Indore, 452 001, Madhya Pradesh, India.
authors.forename: Shunmugiah V
authors.initials: SV
authors.lastname: Ramesh
authors.affiliation: Department of Plant Pathology, Washington State University, 123 Vogel Plant BiologicalSciences, Pullman, WA, 99164, USA. hrp@wsu.edu.
authors.forename: Hanu R
authors.initials: HR
authors.lastname: Pappu
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D018551:Solanum lycopersicum / Q000821:virology*; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry; D011995:Recombination, Genetic; D017423:Sequence Analysis, RNA; D017865:Tospovirus / Q000235:genetics* / Q000302:isolation & purification; D014481:United States
chemical_list: D012367:RNA, Viral; D012324:RNA-Dependent RNA Polymerase
keywords: Genetic diversity; RNA dependent RNA polymerase; Recombination; Tomato spotted wilt virus; Tospovirus