Molecular and Biological Characterisation of Turnip mosaic virus Isolates Infecting Poppy (Papaversomniferum and P. rhoeas) in Slovakia.

In recent years, the accumulated molecular data of Turnip mosaic virus (TuMV) isolates from various hosts originating from different parts of the world considerably helped to understand the genetic complexity and evolutionary history of the virus. In this work, four complete TuMV genomes (HC9, PK1, MS04, MS15) were characterised from naturally infected cultivated and wild-growing Papaver spp., hosts from which only very scarce data were available previously. Phylogenetic analyses showed the affiliation of Slovak Papaver isolates to the world-B and basal-B groups. The PK1 isolate showed a novel intra-lineage recombination pattern, further confirming the important role of recombination in the shaping of TuMV genetic diversity. Biological assays indicated that the intensity of symptoms in experimentally inoculated oilseed poppy are correlated to TuMV accumulation level in leaves. This is the first report of TuMV in poppy plants in Slovakia.

Opium poppy mosaic virus, a new umbravirus isolated from Papaver somniferum in New Zealand.

A novel virus, tentatively named "opium poppy mosaic virus" (OPMV), was isolated from Papaver somniferum (opium poppy) with leaf mosaic and mottling symptoms in Auckland, New Zealand, in 2006. The virus was mechanically transmitted to herbaceous plants of several species, in which it induced local and/or systemic symptoms. No virus particles were observed by electron microscopy in the diseased P. somniferum or any of the symptomatic herbaceous plants. The complete genomic sequence of 4230 nucleotides contains four open reading frames (ORF) and is most closely related (59.3 %) to tobacco bushy top virus, a member of the genus Umbravirus. These data suggest that OPMV is a new umbravirus.

Analysis of developmental control genes using virus-induced gene silencing.

A consistent challenge in studying the evolution of developmental processes has been the problem of explicitly assessing the function of developmental control genes in diverse species. In recent years, virus-induced gene silencing (VIGS) has proved to be remarkably adaptable and efficient in silencing developmental control genes in species across the angiosperms. Here we describe proven protocols for Nicotiana benthamiana and Papaver somniferum, representing a core and basal eudicot species.

Virus-induced gene silencing is an effective tool for assaying gene function in the basal eudicot species Papaver somniferum (opium poppy).

Virus-induced gene silencing (VIGS) is an attractive method for assaying gene function in species that are resistant to conventional genetic approaches. However, VIGS has been shown to be effective in only a few, closely related plant species. Tobacco rattle virus (TRV), a bipartite RNA virus, has a wide host range and so in principle could serve as an efficient vector for VIGS in a diverse array of plant species. Here we show that a vector based on TRV sequences is effective at silencing the endogenous phytoene desaturase (PapsPDS) gene in Papaver somniferum (opium poppy). We show that this vector does not compromise the growth or reproduction of poppy and the plants did not display viral symptoms. The silencing of PapsPDS resulted in a significant reduction in PapsPDS mRNA and a concomitant photobleached phenotype. The ability to rapidly assay gene function in P. somniferum will be valuable in manipulation of the opiate pathway in this pharmaceutically important species. We suggest that our vacuum infiltration method used to deliver TRV-based vectors into poppy is a promising approach for expanding VIGS to diverse angiosperm species in which traditional delivery methods fail to induce VIGS. Furthermore, these studies demonstrate the utility of TRV-VIGS for probing gene function in a basal eudicot species that is phylogenetically distant from model plant species.