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1.
Immunol Lett ; 228: 83-85, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33002511

RESUMEN

Previous research demonstrates that, in clinically relevant concentrations, azithromycin can boost the ability of RNA viruses to induce type 1 interferon by amplifying the expression and virally-mediated activation of MDA5. O-GlcNAcylation of MAVS, a down-stream target of MDA5, renders it more effective for type 1 interferon induction. High-dose glucosamine administration up-regulates O-GlcNAcylation by increasing the cellular pool of UDP-N-acetylglucosamine. Hence, it is proposed that joint administration of azithromycin and high-dose glucosamine, early in the course of RNA virus infections, may interact in a complementary fashion to aid their control by enhancing type 1 interferon induction.


Asunto(s)
Antivirales/uso terapéutico , Azitromicina/uso terapéutico , Glucosamina/uso terapéutico , Interferón Tipo I/metabolismo , Infecciones por Virus ARN/tratamiento farmacológico , Virus ARN/inmunología , Animales , Quimioterapia Combinada , Interacciones Huésped-Patógeno , Humanos , Infecciones por Virus ARN/inmunología , Infecciones por Virus ARN/metabolismo , Infecciones por Virus ARN/virología , Virus ARN/patogenicidad
2.
Int J Mol Sci ; 21(19)2020 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-33027943

RESUMEN

While the potato spindle tuber viroid (PSTVd) variant, PSTVd-Dahlia (PSTVd-D or PSTVd-Dwt) induces very mild symptoms in tomato cultivar 'Rutgers', PSTVd-Intermediate (PSTVd-I or PSTVd-Iwt) induces severe symptoms. These two variants differ by nine nucleotides, of which six mutations are located in the terminal left (TL) to the pathogenicity (P) domains. To evaluate the importance of mutations located in the TL to the P domains, ten types of point mutants were created by swapping the nucleotides between the two viroid variants. Bioassay in tomato plants demonstrated that two mutants created on PSTVd-Iwt at positions 42 and 64 resulted in symptom attenuation. Phenotypic and RT-qPCR analysis revealed that mutation at position 42 of PSTVd-Iwt significantly reduced disease severity and accumulation of the viroid, whereas mutation at position 64 showed a significant reduction in stunting when compared to the PSTVd-Iwt infected plant. RT-qPCR analysis on pathogenesis-related protein 1b1 and chalcone synthase genes showed a direct correlation with symptom severity whereas the expansin genes were down-regulated irrespective of the symptom severity. These results indicate that the nucleotides at positions 42 and 64 are in concert with the ones at positions 43, 310, and 311/312, which determines the slower and stable accumulation of PSTVd-D without eliciting excessive host defense responses thus contributing in the attenuation of disease symptom.


Asunto(s)
Dahlia/química , Enfermedades de las Plantas/genética , Solanum lycopersicum/genética , Viroides/efectos de los fármacos , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/virología , Nucleótidos/genética , Enfermedades de las Plantas/virología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Virus de Plantas/efectos de los fármacos , Virus de Plantas/patogenicidad , Virus ARN/genética , Virus ARN/patogenicidad , ARN Viral/genética , Viroides/patogenicidad
3.
Sci Rep ; 10(1): 4129, 2020 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-32139777

RESUMEN

Beet necrotic yellow vein virus (BNYVV) is the cause of rhizomania, an important disease of sugar beet around the world. The multipartite genome of the BNYVV contains four or five single-stranded RNA that has been used to characterize the virus. Understanding genome composition of the virus not only determines the degree of pathogenicity but also is required to development of resistant varieties of sugar beet. Resistance to rhizomania has been conferred to sugar beet varieties by conventional breeding methods or modern genome engineering tools. However, over time, viruses undergo genetic alterations and develop new variants to break crop resistance. Here, we report the occurrence of genetic reassortment and emergence of new variants of BNYVV among the isolates of Thrace and Asia Minor (modern-day Turkey). Our findings indicate that the isolates harbor European A-type RNA-2 and RNA-3, nevertheless, RNA-5 is closely related to East Asian J-type. Furthermore, RNA-1 and RNA-4 are either derived from A, B, and P-types or a mixture of them. The RNA-5 factor which enhance the pathogenicity, is rarely found in the isolates studied (20%). The creation of new variants of the virus emphasizes the necessity to develop new generation of resistant crops. We anticipate that these findings will be useful for future genetic characterization and evolutionary studies of BNYVV, as well as for developing sustainable strategies for the control of this destructive disease.


Asunto(s)
Beta vulgaris/virología , Enfermedades de las Plantas/virología , Virus de Plantas/patogenicidad , Virus ARN/patogenicidad , Beta vulgaris/genética , Ensayo de Inmunoadsorción Enzimática , Enfermedades de las Plantas/genética , Raíces de Plantas/genética , Raíces de Plantas/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
4.
Virology ; 542: 28-33, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31957663

RESUMEN

Horizontal pollen transmission by the raspberry bushy dwarf virus 1b deletion mutant (RBΔ1bstop), which is defective in virus virulence, was significantly decreased compared to wild-type raspberry bushy dwarf virus (wtRBDV). We assessed accumulation of viral genomic (g) RNAs in pollen grains from RBΔ1bstop-infected plants and found that the pollen grains had less viral gRNA than those from wtRBDV-infected plants. In addition, pollen grains from 1b-expressing transgenic plants (1b-plants) infected with RBΔ1bstop were more efficient in horizontal virus transmission to healthy plants after pollination than pollen from RBΔ1bstop-infected wild type plants. Moreover, viral gRNA accumulation in pollen grains from RBΔ1bstop-infected 1b-plants was higher than in pollen from RBΔ1bstop-infected wild type plants. We suggest that 1b increases the amount of viral gRNAs released from elongating pollen grains.


Asunto(s)
Genes Virales , Enfermedades de las Plantas/virología , Virus de Plantas/genética , Polen/virología , Rubus/virología , Transmisión de Enfermedad Infecciosa , Hibridación in Situ , Mutación , Virus de Plantas/patogenicidad , Plantas Modificadas Genéticamente , Polinización , Virus ARN/genética , Virus ARN/patogenicidad , ARN Viral/genética , ARN Viral/metabolismo , Rubus/fisiología , Nicotiana/genética , Nicotiana/fisiología , Nicotiana/virología
5.
Sci Rep ; 7(1): 6258, 2017 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-28740210

RESUMEN

Parasites and pathogens of the honey bee (Apis mellifera) are key factors underlying colony losses, which are threatening the beekeeping industry and agriculture as a whole. To control the spread and development of pathogen infections within the colony, honey bees use plant resins with antibiotic activity, but little is known about the properties of other substances, that are mainly used as a foodstuff, for controlling possible diseases both at the individual and colony level. In this study, we tested the hypothesis that pollen is beneficial for honey bees challenged with the parasitic mite Varroa destructor associated to the Deformed Wing Virus. First, we studied the effects of pollen on the survival of infested bees, under laboratory and field conditions, and observed that a pollen rich diet can compensate the deleterious effects of mite parasitization. Subsequently, we characterized the pollen compounds responsible for the observed positive effects. Finally, based on the results of a transcriptomic analysis of parasitized bees fed with pollen or not, we developed a comprehensive framework for interpreting the observed effects of pollen on honey bee health, which incorporates the possible effects on cuticle integrity, energetic metabolism and immune response.


Asunto(s)
Abejas/inmunología , Dieta , Interacciones Huésped-Parásitos , Proteínas de Insectos/genética , Infestaciones por Ácaros/parasitología , Polen/metabolismo , Animales , Apicultura , Abejas/genética , Abejas/parasitología , Abejas/virología , Hipersensibilidad a las Drogas , Virus ARN/patogenicidad , Transcriptoma , Varroidae/patogenicidad
6.
Mol Plant Pathol ; 18(6): 864-877, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-28390168

RESUMEN

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.


Asunto(s)
Virus de Plantas/genética , Solanum tuberosum/virología , ADN Complementario/genética , Evolución Molecular , Genoma Viral/genética , Genotipo , Virus de Plantas/patogenicidad , Virus ARN/genética , Virus ARN/patogenicidad , Recombinación Genética/genética
7.
Virology ; 503: 6-11, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28073069

RESUMEN

Gentian ovary ring-spot virus (GORV) infected gentian plants by pollination with GORV-infected gentian pollen grains, but the virus was not horizontally transmitted to gentian plants by transfer of pollen from GORV-infected Nicotiana benthamiana plants. However, N. benthamiana plants were infected with the virus by pollination with infected gentian pollen as well as by pollination with infected N. benthamiana pollen. When infected gentian pollen grains were placed on N. benthamiana stigmas, germinating pollen tubes penetrated into the stigmas and the styles (stigma-style). Virus infection occurred during penetration of the stigma-style, and the virus subsequently spread systemically to the mother plant. On the other hand, most infected N. benthamiana pollen grains failed to germinate on gentian stigmas, and virus infections were not detected in the stigma-style.


Asunto(s)
Nicotiana/virología , Enfermedades de las Plantas/virología , Virus de Plantas/patogenicidad , Tubo Polínico/virología , Polen/virología , Virus ARN/patogenicidad
8.
Philos Trans R Soc Lond B Biol Sci ; 367(1604): 2881-92, 2012 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-22966143

RESUMEN

Many serious emerging zoonotic infections have recently arisen from bats, including Ebola, Marburg, SARS-coronavirus, Hendra, Nipah, and a number of rabies and rabies-related viruses, consistent with the overall observation that wildlife are an important source of emerging zoonoses for the human population. Mechanisms underlying the recognized association between ecosystem health and human health remain poorly understood and responding appropriately to the ecological, social and economic conditions that facilitate disease emergence and transmission represents a substantial societal challenge. In the context of disease emergence from wildlife, wildlife and habitat should be conserved, which in turn will preserve vital ecosystem structure and function, which has broader implications for human wellbeing and environmental sustainability, while simultaneously minimizing the spillover of pathogens from wild animals into human beings. In this review, we propose a novel framework for the holistic and interdisciplinary investigation of zoonotic disease emergence and its drivers, using the spillover of bat pathogens as a case study. This study has been developed to gain a detailed interdisciplinary understanding, and it combines cutting-edge perspectives from both natural and social sciences, linked to policy impacts on public health, land use and conservation.


Asunto(s)
Quirópteros/virología , Enfermedades Transmisibles Emergentes/prevención & control , Virus ARN/patogenicidad , Zoonosis/transmisión , Migración Animal , Animales , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/veterinaria , Enfermedades Transmisibles Emergentes/virología , Vectores de Enfermedades , Ecosistema , Política Ambiental , Conducta Alimentaria , Salud Global/legislación & jurisprudencia , Humanos , Dinámica Poblacional
9.
Plant Signal Behav ; 6(9): 1402-4, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21852753

RESUMEN

Salicylic acid (SA) is a critical signal for activation of both local and systemic resistance responses. However, SA-deficient plants adapt to RNA virus infections better, which show a less-severe symptom and less reactive oxygen species (ROS) accumulation. The higher levels of reduced glutathione (GSH) and reduced ascorbic acid (AsA) in SA-deficient plants may contribute to their alleviated symptoms, which are consistent with their higher expression levels of dehydroascorbate reductase gene (DHAR) and glutathione reductase gene (GR). High-dose AsA or GSH treatment could alleviate the symptom and inhibit virus replication after 20 days, but ROS eliminators could not imitate the effect of AsA or GSH. The data show a new link between SA and AsA/GSH-mediated redox homeostasis.


Asunto(s)
Glutatión Reductasa/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Virus ARN/patogenicidad , Ácido Salicílico/metabolismo , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Ácido Ascórbico/farmacología , Glutatión/farmacología , Glutatión Reductasa/genética , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/virología , Replicación Viral/efectos de los fármacos
10.
Virol J ; 8: 335, 2011 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-21718549

RESUMEN

BACKGROUND: Beet Necrotic Yellow Vein virus (BNYVV) is a member of the genus Benyvirus causing a worldwide sugar beet disease rhizomania. BNYVV contains four or five plus-sense single stranded RNAs. In altered selective conditions, multipartite RNA viruses of plant are prone to undergoing internal deletions, thus turning into Defective RNAs (D RNAs). Although several D RNAs have been reported in BNYVV infection, the spontaneous internal deletion mutants responsible for severe symptom in systemic host Nicotiana benthamiana (N. benthamiana) are not described so far. RESULTS: Systemic host N. benthamiana was inoculated by Chinese BNYVV isolates. RT-PCR and Northern blot showed that the D RNAs forms of BNYVV RNA3 were present in the systemic infection of the N. benthamiana. Three distinct D-RNA3s, named as D-RNA 3α, D-RNA 3ß and D-RNA 3γ, were made into infectious clones. When inoculated on the N. benthamiana, the in vitro transcripts of D forms exhibited more stable than that of wild-type RNA3 in systemic movement. Among the detected mutant, the p25 protein frame-shift mutant (D-RNA3α) induced obvious necrotic lesions on Tetragonia.expansa (T. expansa) and pronounced systemic symptom on the N. benthamiana. The D-RNA3α was further mutated artificially to pre-terminate the downstream N protein, leading to the abolishment of the pathogenicity, indicating the N protein was responsible for the necrotic symptom. CONCLUSION: Our studies demonstrated the internal deletion mutants of BNYVV-RNA3 were spontaneously generated in the systemic infection on N. benthamiana. The internal deletions didn't affect the efficient replication of D-RNA3s, instead by improving the stability and pathogenicity of RNA3 in the systemic host N. benthamiana. Besides, our results also suggested the downstream N protein of RNA3, but not the upstream p25 protein, may play an important role in the systemic infection on N. benthamiana.


Asunto(s)
Nicotiana/virología , Virus de Plantas/genética , Virus de Plantas/aislamiento & purificación , Virus ARN/genética , Virus ARN/aislamiento & purificación , ARN Viral/genética , Eliminación de Secuencia , Secuencia de Aminoácidos , Secuencia de Bases , Beta vulgaris , Datos de Secuencia Molecular , Enfermedades de las Plantas/virología , Virus de Plantas/patogenicidad , Virus ARN/patogenicidad , Proteínas Virales/genética , Virulencia , Factores de Virulencia/genética , Replicación Viral
11.
Phytopathology ; 101(6): 718-24, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21303211

RESUMEN

The genome of most Beet necrotic yellow vein virus (BNYVV) isolates is comprised of four RNAs. The ability of certain isolates to overcome Rz1-mediated resistance in sugar beet grown in the United States and Europe is associated with point mutations in the pathogenicity factor P25. When the virus is inoculated mechanically into sugar beet roots at high density, the ability depends on an alanine to valine substitution at P25 position 67. Increased aggressiveness is shown by BNYVV P type isolates, which carry an additional RNA species that encodes a second pathogenicity factor, P26. Direct comparison of aggressive isolates transmitted by the vector, Polymyxa betae, has been impossible due to varying population densities of the vector and other soilborne pathogens that interfere with BNYVV infection. Mechanical root inoculation and subsequent cultivation in soil that carried a virus-free P. betae population was used to load P. betae with three BNYVV isolates: a European A type isolate, an American A type isolate, and a P type isolate. Resistance tests demonstrated that changes in viral aggressiveness towards Rz1 cultivars were independent of the vector population. This method can be applied to the study of the synergism of BNYVV with other P. betae-transmitted viruses.


Asunto(s)
Beta vulgaris/inmunología , Beta vulgaris/virología , Enfermedades de las Plantas/virología , Inmunidad de la Planta/genética , Virus de Plantas/genética , Plasmodiophorida/virología , Beta vulgaris/genética , Beta vulgaris/parasitología , Europa (Continente) , Variación Genética , Interacciones Huésped-Patógeno , Necrosis , Fenotipo , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/estadística & datos numéricos , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Raíces de Plantas/genética , Raíces de Plantas/inmunología , Raíces de Plantas/parasitología , Raíces de Plantas/virología , Virus de Plantas/inmunología , Virus de Plantas/patogenicidad , Plasmodiophorida/patogenicidad , Mutación Puntual , Virus ARN/genética , Virus ARN/inmunología , Virus ARN/patogenicidad , ARN Viral/análisis , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Suelo/parasitología , Estados Unidos
12.
Virology ; 402(1): 41-51, 2010 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-20350737

RESUMEN

Live-cell fluorescence microscopy was used to investigate the third triple gene block protein (TGB3) of potato mop-top pomovirus and its role in assisted targeting of TGB2 to plasmodesmata (PD). Wild-type and mutant TGB3 proteins were expressed under the control of the 35S promoter or from a virus reporter clone. Assisted targeting of TGB2 to PD was optimal when the proteins were expressed from a bicistronic plasmid in the relative ratios expected in a virus infection, suggesting that excess TGB3 inhibited PD localisation. Contrary to the generally accepted view, bimolecular fluorescence complementation showed that the TGB3 N terminus is located in the cytosol. Mutational analysis to dissect TGB3 sub domain functions showed that PD targeting was mediated by a composite signal comprising an ER-lumenal tyrosine-based motif and the C-terminal transmembrane domain. Mutation of either of these domains also abolished cell-to-cell movement of the virus. The results are discussed in the context of TGB3 membrane topology.


Asunto(s)
Retículo Endoplásmico/virología , Proteínas de Movimiento Viral en Plantas/metabolismo , Virus de Plantas/patogenicidad , Virus ARN/patogenicidad , Solanum tuberosum/virología , Citosol/química , Microscopía Fluorescente , Plasmodesmos/química , Unión Proteica , Transporte de Proteínas
13.
Transgenic Res ; 19(5): 915-22, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20127510

RESUMEN

Agrobacterium rhizogenes-transformed sugar beet hairy roots, expressing dsRNA from the Beet necrotic yellow vein virus replicase gene, were used as a novel approach to assess the efficacy of three intron-hairpin constructs at conferring resistance to rhizomania disease. Genetically engineered roots were similar in morphology to wild type roots but were characterized by a profound abundancy, rapid growth rate and, in some cases, plagiotropic development. Upon challenge inoculation, seedlings showed a considerable delay in symptom development compared to untransformed or vector-transformed seedlings, expressing dsRNA from an unrelated source. The transgenic root system of almost all seedlings contained no or very low virus titer while the non-transformed aerial parts of the same plants were found infected, leading to the conclusion that the hairy roots studied were effectively protected against the virus. This readily applicable novel method forms a plausible approach to preliminarily evaluate transgenic rhizomania resistance before proceeding in transformation and whole plant regeneration of sugar beet, a tedious and time consuming process for such a recalcitrant crop species.


Asunto(s)
Beta vulgaris/genética , Enfermedades de las Plantas/prevención & control , Virus de Plantas/genética , Plantas Modificadas Genéticamente , Interferencia de ARN , Virus ARN/genética , ARN Bicatenario/genética , ARN Interferente Pequeño/genética , ARN Viral/genética , ARN Polimerasa Dependiente del ARN/genética , Proteínas Virales/genética , Beta vulgaris/microbiología , Beta vulgaris/virología , Vectores Genéticos/genética , Inmunidad Innata/genética , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Raíces de Plantas/ultraestructura , Raíces de Plantas/virología , Virus de Plantas/patogenicidad , Plantas Modificadas Genéticamente/genética , Plasmodiophorida/virología , Virus ARN/patogenicidad , Rhizobium/genética , Plantones
14.
J Gen Virol ; 90(Pt 12): 3051-3056, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19726609

RESUMEN

For a better understanding of the functionality and pathogenicity of beet soil-borne virus (BSBV), full-length cDNA clones have been constructed for the three genomic RNAs. With the aim of assessing their effectiveness and relative contribution to the virus housekeeping functions, transcripts were inoculated on Chenopodium quinoa and Beta macrocarpa leaves using five genome combinations. Both RNAs-1 (putative replicase) and -3 (putative movement proteins) proved to be essential for virus replication in planta and symptom production on C. quinoa, whereas RNA-2 (putative coat protein, CP, and a read-through domain, RT) was not. No symptoms were recorded on B. macrocarpa, but viral RNAs were detected. In both host plants, the 19 kDa CP was detected by Western blotting as well as a 115 kDa protein corresponding to the CP-RT.


Asunto(s)
Chenopodium quinoa/virología , Clonación Molecular , Hojas de la Planta/virología , Virus de Plantas/patogenicidad , Virus ARN/patogenicidad , ARN Viral/genética , Beta vulgaris/virología , Datos de Secuencia Molecular , Enfermedades de las Plantas/virología , Virus de Plantas/genética , Virus de Plantas/crecimiento & desarrollo , Virus ARN/genética , Virus ARN/crecimiento & desarrollo , ARN Viral/metabolismo , Análisis de Secuencia de ADN
15.
J Virol ; 83(20): 10761-9, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19656871

RESUMEN

Recognition of virus presence via RIG-I (retinoic acid inducible gene I) and/or MDA5 (melanoma differentiation-associated protein 5) initiates a signaling cascade that culminates in transcription of innate response genes such as those encoding the alpha/beta interferon (IFN-alpha/beta) cytokines. It is generally assumed that MDA5 is activated by long molecules of double-stranded RNA (dsRNA) produced by annealing of complementary RNAs generated during viral infection. Here, we used an antibody to dsRNA to show that the presence of immunoreactivity in virus-infected cells does indeed correlate with the ability of RNA extracted from these cells to activate MDA5. Furthermore, RNA from cells infected with encephalomyocarditis virus or with vaccinia virus and precipitated with the anti-dsRNA antibody can bind to MDA5 and induce MDA5-dependent IFN-alpha/beta production upon transfection into indicator cells. However, a prominent band of dsRNA apparent in cells infected with either virus does not stimulate IFN-alpha/beta production. Instead, stimulatory activity resides in higher-order structured RNA that contains single-stranded RNA and dsRNA. These results suggest that MDA5 activation requires an RNA web rather than simply long molecules of dsRNA.


Asunto(s)
ARN Helicasas DEAD-box/metabolismo , Virus ARN/patogenicidad , ARN Viral/química , ARN Viral/inmunología , Animales , Línea Celular , Chlorocebus aethiops , Células HeLa , Humanos , Helicasa Inducida por Interferón IFIH1 , Interferón-alfa/inmunología , Interferón-alfa/metabolismo , Interferón beta/inmunología , Interferón beta/metabolismo , Ratones , ARN Bicatenario/genética , ARN Bicatenario/inmunología , ARN Bicatenario/metabolismo , ARN Viral/genética , Transducción de Señal , Células Vero
16.
J Gen Virol ; 90(Pt 3): 759-763, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19218223

RESUMEN

Beet necrotic yellow vein virus (BNYVV) A type isolates E12 and S8, originating from areas where resistance-breaking had or had not been observed, respectively, served as starting material for studying the influence of sequence variations in BNYVV RNA 3 on virus accumulation in partially resistant sugar beet varieties. Sub-isolates containing only RNAs 1 and 2 were obtained by serial local lesion passages; biologically active cDNA clones were prepared for RNAs 3 which differed in their coding sequences for P25 aa 67, 68 and 129. Sugar beet seedlings were mechanically inoculated with RNA 1+2/RNA 3 pseudorecombinants. The origin of RNAs 1+2 had little influence on virus accumulation in rootlets. E12 RNA 3 coding for V(67)C(68)Y(129) P25, however, enabled a much higher virus accumulation than S8 RNA 3 coding for A(67)H(68)H(129) P25. Mutants revealed that this was due only to the V(67) 'GUU' codon as opposed to the A(67) 'GCU' codon.


Asunto(s)
Sustitución de Aminoácidos , Beta vulgaris/virología , Enfermedades de las Plantas/virología , Raíces de Plantas/virología , Virus ARN/patogenicidad , Plantones/virología , Proteínas Virales/genética , Alanina/química , Datos de Secuencia Molecular , Virus ARN/genética , Virus ARN/metabolismo , Virus ARN/fisiología , ARN Bacteriano/genética , ARN Viral/genética , ARN Viral/metabolismo , Análisis de Secuencia de ADN , Valina/química , Proteínas Virales/química , Proteínas Virales/metabolismo
17.
Mol Plant Pathol ; 10(1): 129-41, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19161359

RESUMEN

Rhizomania is a soil-borne disease that occurs throughout the major sugar beet growing regions of the world, causing severe yield losses in the absence of effective control measures. It is caused by Beet necrotic yellow vein virus (BNYVV), which is transmitted by the obligate root-infecting parasite Polymyxa betae. BNYVV has a multipartite RNA genome with all natural isolates containing four RNA species, although some isolates have a fifth RNA. The larger RNA1 and RNA2 contain the housekeeping genes of the virus and are always required for infection, whereas the smaller RNAs are involved in pathogenicity and vector transmission. RNA5-containing isolates are restricted to Asia and some parts of Europe, and these isolates tend to be more aggressive. With no acceptable pesticides available to restrict the vector, the control of rhizomania is now achieved almost exclusively through the use of resistant cultivars. A single dominant resistance gene, Rz1, has been used to manage the disease worldwide in recent years, although this gene confers only partial resistance. More recently, new variants of BNYVV have evolved (both with and without RNA5) that are able to cause significant yield penalties on resistant cultivars. These isolates are not yet widespread, but their appearance has resulted in accelerated searches for new sources of resistance to both the virus and the vector. Combined virus and vector resistance, achieved either by conventional or transgenic breeding, offers the sugar beet industry a new approach in its continuing struggle against rhizomania.


Asunto(s)
Beta vulgaris/virología , Enfermedades de las Plantas/virología , Virus ARN/patogenicidad , Genoma Viral , Plantas Modificadas Genéticamente/virología , Virus ARN/genética
18.
Mol Plant Pathol ; 9(6): 741-51, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19019003

RESUMEN

Rhizomania is one of the most devastating sugar beet diseases. It is caused by Beet necrotic yellow vein virus (BNYVV), which induces abnormal rootlet proliferation. To understand better the physiological and molecular basis of the disorder, transcriptome analysis was performed by restriction fragment differential display polymerase chain reaction (RFDD-PCR), which provided differential gene expression profiles between non-infected and infected sugar beet roots. Two distinct viral isolates were used to detect specific or general virus-induced genes. Differentially expressed genes were selected and identified by sequence analysis, followed by reverse Northern and reverse transcriptase PCR experiments. These latter analyses of different plants (Beta vulgaris and Beta macrocarpa) infected under distinct standardized conditions revealed specific and variable expressions. Candidate genes were linked to cell development, metabolism, defence signalling and oxidative stress. In addition, the expression of already characterized genes linked to defence response (pathogenesis-related protein genes), auxin signalling and cell elongation was also studied to further examine some aspects of the disease. Differential expression was retrieved in both B. vulgaris and B. macrocarpa. However, some candidate genes were found to be deregulated in only one plant species, suggesting differential response to BNYVV or specific responses to the BNYVV vector.


Asunto(s)
Beta vulgaris/genética , Beta vulgaris/virología , Expresión Génica/genética , Raíces de Plantas/genética , Raíces de Plantas/virología , Virus de Plantas/patogenicidad , Northern Blotting , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Virus de Plantas/genética , Reacción en Cadena de la Polimerasa , Virus ARN/genética , Virus ARN/patogenicidad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
19.
Transgenic Res ; 17(2): 219-28, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17431806

RESUMEN

Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) is one of the most devastating sugar beet diseases. Sugar beet plants engineered to express a 0.4 kb inverted repeat construct based on the BNYVV replicase gene accumulated the transgene mRNA to similar levels in leaves and roots, whereas accumulation of the transgene-homologous siRNA was more pronounced in roots. The roots expressed high levels of resistance to BNYVV transmitted by the vector, Polymyxa betae. Resistance to BNYVV was not decreased following co-infection of the plants with Beet soil borne virus and Beet virus Q that share the same vector with BNYVV. Similarly, co-infection with the aphid-transmitted Beet mild yellowing virus, Beet yellows virus (BYV), or with all of the aforementioned viruses did not affect the resistance to BNYVV, while they accumulated in roots. These viruses are common in most of the sugar beet growing areas in Europe and world wide. However, there was a competitive interaction between BYV and BMYV in sugar beet leaves, as infection with BYV decreased the titres of BMYV. Other interactions between the viruses studied were not observed. The results suggest that the engineered resistance to BNYVV expressed in the sugar beets of this study is efficient in roots and not readily compromised following infection of the plants with heterologous viruses.


Asunto(s)
Áfidos/virología , Beta vulgaris/virología , Enfermedades de las Plantas/virología , Virus de Plantas/patogenicidad , Plantas Modificadas Genéticamente/virología , Virus ARN/patogenicidad , ARN Bicatenario/genética , Animales , Beta vulgaris/genética , Enfermedades de las Plantas/genética , Hojas de la Planta/citología , Hojas de la Planta/virología , Raíces de Plantas/citología , Raíces de Plantas/virología , Virus de Plantas/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Virus ARN/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transgenes/fisiología
20.
Pak J Biol Sci ; 10(9): 1414-21, 2007 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-19069951

RESUMEN

In the present study, we investigated on the experimental host range of RYMV among plant species most of which are frequently encountered in rice-growing environments of west and central African savannahs. Only seven out of 66 plant species inoculated were infected by RYMV. All susceptible plant species belonged to the Poaceae family and three of them (Chloris prieuri, Eragrostis cilianensis and Shoenefeldia gracilis) were reported for the first time. Symptoms were conspicuous and persistent in most species but disappeared totally in older plants of some host species such as S. gracilis and Eragrostis tenella. Therefore, surveys for identification ofRYMV wild hosts should be conducted before the flowering stage. Virus-host Interactions were studied between 15 RYMV isolates of different strains and 10 wild host species. Differential reactions were obtained in the crow-foot grass Dactyloctenium aegyptium which was susceptible to five of the fifteen isolates. All other plants were susceptible to the whole set of virus isolates. Altogether, this study underlined the narrowness of RYMV host range and pointed out the complexity of interactions between the virus and its hosts, especially the rationale behind overcoming host barriers.


Asunto(s)
Oryza/virología , Virus de Plantas/patogenicidad , Poaceae/virología , Virus ARN/patogenicidad , África , Animales , Susceptibilidad a Enfermedades , Humanos , Enfermedades de las Plantas/virología , Extractos Vegetales
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