Complete nucleotide sequence of tobacco necrosis virus strain DH and genes required for RNA replication and virus movement.

Abstract

The complete genome sequence of tobacco necrosis virus strain D (Hungarian isolate, TNV-D H ) was determined. The genome (3762 nt) has an organization identical to that reported for TNV-D. Highly infectious synthetic transcripts from a fulllength TNV-D H cDNA clone were prepared, the first infectious necrovirus transcript reported. This clone was used for reverse genetic studies to map the viral genes required for replication and movement. Protoplast inoculation with ∆22 and ∆82 mutants revealed that both the 22 kDa and 82 kDa gene products are required for RNA replication. Although the products of three small central genes (p7 1 , p7a and p7b) were not essential for RNA replication in protoplasts, mutations in these ORFs prevented infection of plants. In contrast, viral RNA accumulation and cell-to-cell movement were observed in the inoculated, but not the systemically infected, leaves of Nicotiana benthamiana challenged with RNA lacking the intact coat protein (CP) gene. These results strongly suggest that p7 1 , p7a, p7b and CP are involved in TNV-D H cell-to-cell and longdistance movement, respectively.

Biology and molecular characterization of necroviruses affecting Olea europaea L.: a review

“…Its identification was based on the overall genome sequence identity with that of TNV-D (English isolate), obtained from bean plant (Coutts et al 1991) and of TNV-D H (Hungarian isolate), obtained from tobacco plants (Molnar et al 1997), 94.8% and 82.9%, respectively ). Several TNV-D serotypes have been referred to in the literature infecting a variety of different host plants, including tulips in Japan from the same site where OLV-1 infections were recorded (Kanematsu et al 2001).…”

Análisis de relaciones estructura-función en el virus del arabesco del Pelargonium.

“…El requerimiento de la CP para el movimiento célula a célula y sistémico varía entre los distintos miembros de la familia Tombusviridae. Así, la CP no es necesaria para el movimiento local del virus de las manchas de las hojas del pepino (Cucumber leaf spot virus, CLSV) y del PoLV, ambos en el género Aureusvirus (Rubino y Russo, 1997;Reade et al, 2003), del virus de la necrosis del tabaco (Tobacco necrosis virus, TNV, Necrovirus) (Molnar et al, 1997), y del RCNMV (Dianthovirus) (Vaewhongs y Lommel, 1995). En este último sin embargo, la CP es estrictamente necesaria para el movimiento a larga distancia, excepto en el huésped N. benthamiana a bajas temperaturas (Xiong et al, 1993).…”

Análisis Funcional De Proteínas Codificadas Por El Virus De La Rotura Del Color De La Flor Del Pelargonium

“…Este aspecto se ha confirmado también en otros componentes de la familia, como el virus del mosaico necrótico del trébol rojo (Red clover necrotic ringspot virus, RCNMV) (género Dianthovirus) [Bates et al, 1995;Takeda et al, 2005;Okamoto et al, 2008], el virus del mosaico del Panicum (Panicum mosaic virus, PMV) (género Panicovirus) [Batten et al, 2006], la cepa D del virus de la necrosis del tabaco (Tobacco necrosis virus D, TNV-D) (género Necrovirus) [Molnár et al, 1997], en dos carmovirus, el virus del arrugamiento del nabo (Turnip crinkle virus, TCV) y el virus de las manchas necróticas del melón (Melon necrotic spot virus, MNSV) [Hacker et al, 1992;White et al, 1995;Genovés et al, 2006], y en el virus del arabesco del Pelargonium (Pelargonium line pattern virus, PLPV), propuesto como miembro de un nuevo género, Pelarspovirus, dentro de la familia Tombusviridae [Castaño et al, 2009].…”

“…The requirement for the translation products of ORFs 1 and 2 for viral replication has so far been verified for two species of the genus Carmovirus, Turnip crinkle virus (TCV) and Melon necrotic spot virus Hacker et al, 1992], as well as for members of other genera of the family Tombusviridae [Castaño et al, 2009;Molnár et al, 1997;White & Nagy, 2004]. In order to confirm that p27 and p86 of PFBV play a similar role, three different mutants were generated using an infectious viral cDNA clone [pSP18-IC; as the template: (i) p27aug -, which lacks the initiation codon of the first two ORFs (p27/p86); (ii) p27stop, bearing two stop codons in tandem that terminate ORF1; and (iii) p27tyr, in which the leaky stop codon of ORF1 has been replaced by a Tyr encoding triplet (Fig.…”

“…Estos resultados son similares a los obtenidos con otros miembros del género Carmovirus [Hacker et al, 1992;White et al, 1995;Genovés et al, 2006] y con otras especies de la familia Tombusviridae Kollár & Burgyán, 1994;Bates et al, 1995;Scholthof et al, 1995b;Molnár et al, 1997;Molinari et al, 1998;Oster et al, 1998;Panaviene et al, 2003;Takeda et al, 2005;Batten et al, 2006;Okamoto et al, 2008], que muestran que en la replicación intervienen como mínimo dos proteínas virales: la RdRp, y un polipéptido adicional de menor tamaño con funciones auxiliares al proceso de síntesis de RNA. La RdRp es la enzima encargada de generar los intermediarios replicativos y, en última instancia, los genomas de la progenie viral, mientras que la falta de motivos reconocibles en la replicasa más pequeña impide anticipar sus funciones concretas.…”