| 1. |
- De Souza, Joao, et al.
(författare)
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The complete nucleotide sequence of sweet potato C6 virus: a carlavirus lacking a cysteine-rich protein
- 2013
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Ingår i: Archives of Virology. - : Springer Science and Business Media LLC. - 0304-8608 .- 1432-8798. ; 158, s. 1393-1396
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Tidskriftsartikel (refereegranskat)abstract
- The complete nucleotide sequence of a sweet potato virus, first identified two decades ago as virus "C-6", was determined in this study. Sequence similarity and phylogenetic analysis clearly place it as a member of a distinct species within the genus Carlavirus, family Betaflexiviridae. Its genome structure was typical for that of other carlaviruses except that the ORF for the cysteine-rich protein was replaced by an ORF encoding a predicted protein with no similarity to any known protein.
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| 2. |
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| 3. |
- Gil, José Fernando, et al.
(författare)
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Comparative Transcriptome Analysis Provides Molecular Insights into the Interaction of Beet necrotic yellow vein virus and Beet soil-borne mosaic virus with Their Host Sugar Beet
- 2020
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Beet necrotic yellow vein virus (BNYVV) and Beet soil-borne mosaic virus (BSBMV) are closely related species, but disease development induced in their host sugar beet displays striking differences. Beet necrotic yellow vein virus induces excessive lateral root (LR) formation, whereas BSBMV-infected roots appear asymptomatic. A comparative transcriptome analysis was performed to elucidate transcriptomic changes associated with disease development. Many differentially expressed genes (DEGs) were specific either to BNYVV or BSBMV, although both viruses shared a high number of DEGs. Auxin biosynthesis pathways displayed a stronger activation by BNYVV compared to BSBMV-infected plants. Several genes regulated by auxin signalling and required for LR formation were exclusively altered by BNYVV. Both viruses reprogrammed the transcriptional network, but a large number of transcription factors involved in plant defence were upregulated in BNYVV-infected plants. A strong activation of pathogenesis-related proteins by both viruses suggests a salicylic acid or jasmonic acid mediated-defence response, but the data also indicate that both viruses counteract the SA-mediated defence. The ethylene signal transduction pathway was strongly downregulated which probably increases the susceptibility of sugar beet to Benyvirus infection. Our study provides a deeper insight into the interaction of BNYVV and BSBMV with the economically important crop sugar beet.
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| 4. |
- Gil, José Fernando, et al.
(författare)
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Massive up-regulation of LBD transcription factors and EXPANSINs highlights the regulatory programs of rhizomania disease
- 2018
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Ingår i: Molecular Plant Pathology. - : Wiley. - 1464-6722 .- 1364-3703. ; 19, s. 2333-2348
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Tidskriftsartikel (refereegranskat)abstract
- Rhizomania of sugar beet, caused by Beet necrotic yellow vein virus (BNYVV), is characterized by excessive lateral root (LR) formation leading to dramatic reduction of taproot weight and massive yield losses. LR formation represents a developmental process tightly controlled by auxin signaling through AUX/IAA-ARF responsive module and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcriptional network. Several LBD transcription factors play central roles in auxin-regulated LR development and act upstream of EXPANSINS (EXPs), cell wall (CW)-loosening proteins involved in plant development via disruption of the extracellular matrix for CW relaxation and expansion. Here, we present evidence that BNYVV hijacks these auxin-regulated pathways resulting in formation LR and root hairs (RH). We identified an AUX/IAA protein (BvAUX28) as interacting with P25, a viral virulence factor. Mutational analysis indicated that P25 interacts with domains I and II of BvAUX28. Subcellular localization of co-expressed P25 and BvAUX28 showed that P25 inhibits BvAUX28 nuclear localization. Moreover, root-specific LBDs and EXPs were greatly upregulated during rhizomania development. Based on these data, we present a model in which BNYVV P25 protein mimics action of auxin by removing BvAUX28 transcriptional repressor, leading to activation of LBDs and EXPs. Thus, the evidence highlights two pathways operating in parallel and leading to uncontrolled formation of LRs and RHs, the main manifestation of the rhizomania syndrome.
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| 5. |
- Grenville-Briggs, Laura J, et al.
(författare)
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Draft genome of the oomycete pathogen Phytophthora cactorum strain LV007 isolated from European beech (Fagus sylvatica)
- 2017
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Ingår i: Genomics Data. - : Elsevier. - 2213-5960. ; 12, s. 155-156
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Tidskriftsartikel (refereegranskat)abstract
- Phytophthora cactorum is a broad host range phytopathogenic oomycete. P. cactorum strain LV007 was isolated from a diseased European Beech (Fagus sylvatica) in Malmö, Sweden in 2016. The draft genome of P. cactorum strain LV007 is 67.81 Mb. It contains 15,567 contigs and 21,876 predicted protein-coding genes. As reported for other phytopathogenic Phytophthora species, cytoplasmic effector proteins including RxLR and CRN families were identified. The genome sequence has been deposited at DDBJ/ENA/GenBank under the accession NBIJ00000000. The version described in this paper is version NBIJ01000000.
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| 6. |
- Kalyandurg, Pruthvi Balachandra, et al.
(författare)
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Efficient RNA silencing suppression activity of Potato Mop-Top Virus 8K protein is driven by variability and positive selection
- 2019
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Ingår i: Virology. - : Elsevier BV. - 0042-6822 .- 1178-122X. ; 535, s. 111-121
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Tidskriftsartikel (refereegranskat)abstract
- Previously, we investigated the evolution of Potato mop-top virus (PMTV) ORFs. Results indicate that positive selection acts exclusively on an ORF encoding the 8K protein, a weak viral suppressor of RNA silencing (VSR). However, how the extraordinary variability contributes to 8K-mediated RNA silencing suppression remains unknown. Here, we characterized the RNA silencing suppression activity of the 8K protein from seven diverse isolates. We show that 8K encoded by isolate P1 exhibits stronger RNA silencing suppression activity than the 8K protein from six other isolates. Mutational analyses revealed that Ser-50 is critical for these differences. By comparing small RNA profiles we found a lower abundance of siRNAs with U residue at the 5'-terminus after expression of the P1 8K compared to expression of 8K from isolate P125, an isolate with weak VSR activity. These results provide new clues as to the role of positive selection in shaping activities of VSRs.
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| 7. |
- Kalyandurg, Pruthvi Balachandra, et al.
(författare)
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Molecular and pathobiological characterization of 61 Potato mop-top virus full-length cDNAs reveals great variability of the virus in the centre of potato domestication, novel genotypes and evidence for recombination
- 2017
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Ingår i: Molecular Plant Pathology. - : Wiley. - 1464-6722 .- 1364-3703. ; 18, s. 864-877
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Tidskriftsartikel (refereegranskat)abstract
- The evolutionary divergence of Potato mop-top virus (PMTV), a tri-partite, single-stranded RNA virus, is exceptionally low, based on the analysis of sequences obtained from isolates from Europe, Asia and North America. In general, RNA viruses exist as dynamic populations of closely related and recombinant genomes that are subjected to continuous genetic variation. The reason behind the low genetic variation of PMTV remains unclear. The question remains as to whether the low variability is a shared property of all PMTV isolates or is a result of the limited number of isolates characterized so far. We hypothesized that higher divergence of the virus might exist in the Andean regions of South America, the centre of potato domestication. Here, we report high variability of PMTV isolates collected from 12 fields in three locations in the Andean region of Peru. To evaluate PMTV genetic variation in Peru, we generated full-length cDNA clones, which allowed reliable comparative molecular and pathobiological characterization of individual isolates. We found significant divergence of the CP-RT and 8K sequences. The 8K cistron, which encodes a viral suppressor of RNA silencing, was found to be under diversifying selection. Phylogenetic analysis determined that, based on the CP-RT sequence, all PMTV isolates could be categorized into three separate lineages (clades). Moreover, we found evidence for recombination between two clades. Using infectious cDNA clones of the representatives of these two clades, as well as reassortants for the RNA-CP genomic component, we determined the pathobiological differences between the lineages, which we coined as S (for severe) and M (for mild) types. Interestingly, all isolates characterized previously (from Europe, Asia and North America) fall into the S-type clade, whereas most of the Peruvian isolates belong to the M-type. Taken together, our results support the notion of the single introduction of PMTV from the centre of potato origin to Europe, and subsequent spread of the S-type into Asia and USA. This is also supported by the suggested novel classification of isolates based on genetic constellations.
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| 8. |
- Kalyandurg, Pruthvi Balachandra, et al.
(författare)
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Potato Mop-Top Virus Co-Opts the Stress Sensor HIPP26 for Long-Distance Movement
- 2018
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 176, s. 2052-2070
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Tidskriftsartikel (refereegranskat)abstract
- Virus movement proteins facilitate virus entry into the vascular system to initiate systemic infection. The potato mop-top virus (PMTV) movement protein, TGB1, is involved in long-distance movement of both viral ribonucleoprotein complexes and virions. Here, our analysis of TGB1 interactions with host Nicotiana benthamiana proteins revealed an interaction with a member of the heavy metal-associated isoprenylated plant protein family, HIPP26, which acts as a plasma membrane-to-nucleus signal during abiotic stress. We found that knockdown of NbHIPP26 expression inhibited virus long-distance movement but did not affect cell-to-cell movement. Drought and PMTV infection up-regulated NbHIPP26 gene expression, and PMTV infection protected plants from drought. In addition, NbHIPP26 promoter-reporter fusions revealed vascular tissue-specific expression. Mutational and biochemical analyses indicated that NbHIPP26 subcellular localization at the plasma membrane and plasmodesmata was mediated by lipidation (S-acylation and prenylation), as nonlipidated NbHIPP26 was predominantly in the nucleus. Notably, coexpression of NbHIPP26 with TGB1 resulted in a similar nuclear accumulation of NbHIPP26. TGB1 interacted with the carboxyl-terminal CVVM (prenyl) domain of NbHIPP26, and bimolecular fluorescence complementation revealed that the TGB1-HIPP26 complex localized to microtubules and accumulated in the nucleolus, with little signal at the plasma membrane or plasmodesmata. These data support a mechanism where interaction with TGB1 negates or reverses NbHIPP26 lipidation, thus releasing membrane-associated NbHIPP26 and redirecting it via microtubules to the nucleus, thereby activating the drought stress response and facilitating virus long-distance movement.
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| 9. |
- Lukhovitskaya, Nina, et al.
(författare)
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A viral transcription factor exhibits antiviral RNA silencing suppression activity independent of its nuclear localization
- 2014
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Ingår i: Journal of General Virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 95, s. 2831-2837
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Tidskriftsartikel (refereegranskat)abstract
- Viral suppressors of RNA silencing (VSRs) are critical for the success of virus infection and efficient accumulation of virus progeny. The chrysanthemum virus B p12 protein acts as a transcription factor to regulate cell size and proliferation favourable for virus infection. Here, we showed that the p12 protein suppressed RNA silencing and was able to complement a VSR-deficient unrelated virus. Moreover, p12 counter-silencing activity could be uncoupled from its function as a transcription factor in the nucleus. The altered p12 protein, which lacked a nuclear localization signal and was not imported into the nucleus, was able to suppress RNA silencing as efficiently as the native protein. The data revealed new aspects of p12 functioning and identified a novel role for this viral zinc-finger transcription factor. The results provided a general insight into one of the activities of the p12 protein, which appeared to possess more than one function.
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| 10. |
- Lukhovitskaya, Nina, et al.
(författare)
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An RNA Virus-Encoded Zinc-Finger Protein Acts as a Plant Transcription Factor and Induces a Regulator of Cell Size and Proliferation in Two Tobacco Species
- 2013
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Ingår i: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 25, s. 960-973
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Tidskriftsartikel (refereegranskat)abstract
- Plant viruses cause a variety of diseases in susceptible hosts. The disease symptoms often include leaf malformations and other developmental abnormalities, suggesting that viruses can affect plant development. However, little is known about the mechanisms underlying virus interference with plant morphogenesis. Here, we show that a C-4 type zinc-finger (ZF) protein, p12, encoded by a carlavirus (chrysanthemum virus B) can induce cell proliferation, which results in hyperplasia and severe leaf malformation. We demonstrate that the p12 protein activates expression of a regulator of cell size and proliferation, designated upp-L (upregulated by p12), which encodes a transcription factor of the basic/helix-loop-helix family sufficient to cause hyperplasia. The induction of upp-L requires translocation of the p12 protein into the nucleus and ZF-dependent specific interaction with the conserved regulatory region in the upp-L promoter. Our results establish the role of the p12 protein in modulation of host cell morphogenesis. It is likely that other members of the conserved C-4 type ZF family of viral proteins instigate reprogramming of plant development by mimicking eukaryotic transcriptional activators.
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