scholarly journals Olive Mild Mosaic Virus Coat Protein and P6 Are Suppressors of RNA Silencing, and Their Silencing Confers Resistance against OMMV

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 416 ◽  
Author(s):  
Carla Varanda ◽  
Patrick Materatski ◽  
Maria Campos ◽  
Maria Clara ◽  
Gustavo Nolasco ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Defense Mechanism ◽  
Plant Viruses ◽  
Open Reading Frames ◽  
Mild Mosaic ◽  
Suppressor Activity ◽  
Mild Mosaic Virus ◽  
Virus Coat ◽  
Viral Suppressors

RNA silencing is an important defense mechanism in plants, yet several plant viruses encode proteins that suppress this mechanism. In this study, the genome of the Olive mild mosaic virus (OMMV) was screened for silencing suppressors. The full OMMV cDNA and 5 OMMV open reading frames (ORFs) were cloned into the Gateway binary vector pK7WG2, transformed into Agrobacterium tumefaciens, and agroinfiltrated into N. benthamiana 16C plants. CP and p6 showed suppressor activity, with CP showing significantly higher activity than p6, yet activity that was lower than the full OMMV, suggesting a complementary action of CP and p6. These viral suppressors were then used to induce OMMV resistance in plants based on RNA silencing. Two hairpin constructs targeting each suppressor were agroinfiltrated in N. benthamiana plants, which were then inoculated with OMMV RNA. When silencing of both suppressors was achieved, a significant reduction in viral accumulation and symptom attenuation was observed as compared to those of the controls, as well as to when each construct was used alone, proving them to be effective against OMMV infection. This is the first time that a silencing suppressor was found in a necrovirus, and that two independent proteins act as silencing suppressors in a virus member of the Tombusviridae family.

scholarly journals Olive mild mosaic virus coat protein and p6 are suppressors of RNA silencing and their silencing confers resistance against OMMV

2018 ◽  
Author(s):  
CMR Varanda ◽  
P Materatski ◽  
MD Campos ◽  
MIE Clara ◽  
G Nolasco ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Plant Viruses ◽  
Mild Mosaic ◽  
Suppressor Activity ◽  
Complementary Action ◽  
Mild Mosaic Virus ◽  
Silencing Suppression ◽  
Viral Suppressors ◽  
Viral Accumulation

AbstractRNA silencing is an important defense mechanism in plants, yet several plant viruses encode proteins that suppress it. Here the genome of Olive mild mosaic virus (OMMV) was screened for silencing suppressors using a green fluorescent based transient suppression assay. The full OMMV cDNA and 5 different OMMV open reading frames (ORFs) were cloned into Gateway binary destination vector pK7WG2, transformed into Agrobacterium tumefaciens C58C1 and agroinfiltrated into Nicotiana benthamiana 16C plants. Among all ORFs tested, CP and p6 showed suppressor activity, with CP showing a significant higher activity when compared to p6, yet lower than that of the full OMMV. This suggests that OMMV silencing suppression results from a complementary action of both CP and p6.Such discovery led to the use of those viral suppressors in the development of OMMV resistant plants through pathogen-derived resistance (PDR) based on RNA silencing. Two hairpin constructs targeting each suppressor were agroinfiltrated in N. benthamiana plants which were then inoculated with OMMV RNA. When silencing of both suppressors was achieved, a highly significant reduction in viral accumulation and symptom attenuation was observed as compared to that seen when each construct was used alone, and to the respective controls, thus showing clear effectiveness against OMMV infection. Data here obtained indicate that the use of both OMMV viral suppressors as transgenes is a very efficient and promising approach to obtain plants resistant to OMMV.ImportanceOMMV silencing suppressors were determined. Among all ORFs tested, CP and p6 showed suppressor activity, with CP showing a significant higher activity when compared to p6, yet lower than that of the full OMMV, suggesting a complementary action of both CP and p6 in silencing suppression.This is the first time that a silencing suppressor was found in a necrovirus and that two independent proteins act as silencing suppressors in a member of the Tombusviridae family.When silencing of both suppressors was achieved, a highly significant reduction in viral accumulation and symptom attenuation was observed as compared to that seen when each was used alone, thus showing clear effectiveness against OMMV infection. A high percentage of resistant plants was obtained (60%), indicating that the use of both OMMV viral suppressors as transgenes is a very efficient and promising approach to obtain plants resistant to OMMV.

scholarly journals Identification of Divergent Isolates of Banana Mild Mosaic Virus and Development of a New Diagnostic Primer to Improve Detection

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1045
Author(s):  
Marwa Hanafi ◽  
Rachid Tahzima ◽  
Sofiene Ben Kaab ◽  
Lucie Tamisier ◽  
Nicolas Roux ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
High Throughput Sequencing ◽  
Plant Viruses ◽  
Mild Mosaic ◽  
Genome Variability ◽  
Molecular Tests ◽  
Pcr Products ◽  
Reverse Primer ◽  
Mild Mosaic Virus ◽  
Germplasm Accessions

Banana mild mosaic virus (BanMMV) (Betaflexiviridae, Quinvirinae, unassigned species) is a filamentous virus belonging to the Betaflexiviridae family. It infects Musa spp. with a very wide geographic distribution. The genome variability of plant viruses, including the members of the Betaflexiviridae family, makes their molecular detection by specific primers particularly challenging. During routine indexing of the Musa germplasm accessions, a discrepancy was observed between electron microscopy and immunocapture (IC) reverse transcription (RT) polymerase chain reaction (PCR) test results for one asymptomatic accession. Filamentous viral particles were observed while molecular tests failed to amplify any fragment. The accession underwent high-throughput sequencing and two complete genomes of BanMMV with 75.3% of identity were assembled. Based on these sequences and on the 54 coat protein sequences available from GenBank, a new forward primer, named BanMMV CP9, compatible with Poty1, an oligodT reverse primer already used in diagnostics, was designed. A retrospective analysis of 110 different germplasm accessions from diverse origins was conducted, comparing BanMMCP2 and BanMMV CP9 primers. Of these 110 accessions, 16 tested positive with both BanMMCP2 and BanMMV CP9, 3 were positive with only BanMMCP2 and 2 tested positive with only BanMMV CP9. Otherwise, 89 were negative with the two primers and free of flexuous virions. Sanger sequencing was performed from purified PCR products in order to confirm the amplification of the BanMMV sequence for the five accessions with contrasting results. It is highly recommended to use the two primers successively to improve the inclusiveness of the protocol.

scholarly journals Specific amino acids of Olive mild mosaic virus coat protein are involved in transmission by Olpidium brassicae

2011 ◽  
Vol 92 (9) ◽  
pp. 2209-2213 ◽  
Author(s):  
Carla Varanda ◽  
Maria do Rosário Félix ◽  
Cláudio M. Soares ◽  
Solange Oliveira ◽  
Maria Ivone Clara
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Mild Mosaic ◽  
Receptor Binding Site ◽  
Comparative Modelling ◽  
Mild Mosaic Virus ◽  
Olpidium Brassicae ◽  
Virus Coat

Transmission of Olive mild mosaic virus (OMMV) is facilitated by Olpidium brassicae (Wor.) Dang. An OMMV mutant (OMMVL11) containing two changes in the coat protein (CP), asparagine to tyrosine at position 189 and alanine to threonine at position 216, has been shown not to be Olpidium brassicae-transmissible owing to inefficient attachment of virions to zoospores. In this study, these amino acid changes were separately introduced into the OMMV genome through site-directed mutagenesis, and the asparagine-to-tyrosine change was shown to be largely responsible for the loss of transmission. Analysis of the structure of OMMV CP by comparative modelling approaches showed that this change is located in the interior of the virus particle and the alanine-to-threonine change is exposed on the surface. The asparagine-to-tyrosine change may indirectly affect attachment via changes in the conformation of viral CP subunits, altering the receptor binding site and thus preventing binding to the fungal zoospore.

scholarly journals A New Tymovirus Isolated From Solanum quitoense: Characterization and Prevalence in Two Solanaceous Crops in Ecuador

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2246-2251 ◽  
Author(s):  
Juan F. Cornejo-Franco ◽  
Robert A. Alvarez-Quinto ◽  
Samuel Grinstead ◽  
Dimitre Mollov ◽  
Alexander V. Karasev ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Open Reading Frames ◽  
Yellow Mosaic Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mild Mosaic ◽  
Fresh Market ◽  
Certification Programs ◽  
Mild Mosaic Virus ◽  
Polymerase Chain ◽  
Production Areas

Naranjilla (Solanum quitoense Lam.) and tamarillo (S. betaceum Cav.) are two important perennial solanaceous crops grown in Ecuador for the fresh market and juice production. Viruses infecting tamarillo and naranjilla are currently poorly studied, and no clean stock program exists in Ecuador. Here, we report a new virus, provisionally named as naranjilla mild mosaic virus (NarMMV) (genus Tymovirus, family Tymoviridae), isolated from naranjilla grown in an orchard in Pichincha Province, Ecuador. The complete genome of the virus consists of 6,348 nucleotides and encodes three open reading frames typical for members of the genus Tymovirus. Phylogenetically, Chiltepin yellow mosaic virus, Eggplant mosaic virus, and the recently characterized naranjilla chlorotic mosaic virus (NarCMV) were found to be the closest relatives of NarMMV. Unlike NarCMV, the new virus induced mild mosaic in naranjilla and more severe symptoms in tamarillo. Similar to NarCMV, NarMMV was unable to systemically infect potato. Virus surveys found NarMMV prevalent in naranjilla production areas of two provinces of Ecuador, especially where hybrid cultivars of naranjilla were cultivated. NarMMV was also found in field-grown tamarillo. The new virus cross-reacted with antibodies developed against NarCMV. Hence, this antibody will be useful for its field diagnosis using enzyme-linked immunosorbent assay or immunocapture reverse transcription polymerase chain reaction in future virus-free certification programs.

scholarly journals The Potyvirus Silencing Suppressor Protein VPg Mediates Degradation of SGS3 via Ubiquitination and Autophagy Pathways

2016 ◽  
Vol 91 (1) ◽  
Author(s):  
Xiaofei Cheng ◽  
Aiming Wang
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Plant Viruses ◽  
Turnip Mosaic Virus ◽  
Host Protein ◽  
Ubiquitin Proteasome ◽  
Cellular Pathways ◽  
Viral Suppressors ◽  
Interfering Rna ◽  
Innate Antiviral Immunity

ABSTRACT RNA silencing is an innate antiviral immunity response of plants and animals. To counteract this host immune response, viruses have evolved an effective strategy to protect themselves by the expression of viral suppressors of RNA silencing (VSRs). Most potyviruses encode two VSRs, helper component-proteinase (HC-Pro) and viral genome-linked protein (VPg). The molecular biology of the former has been well characterized, whereas how VPg exerts its function in the suppression of RNA silencing is yet to be understood. In this study, we show that infection by Turnip mosaic virus (TuMV) causes reduced levels of suppressor of gene silencing 3 (SGS3), a key component of the RNA silencing pathway that functions in double-stranded RNA synthesis for virus-derived small interfering RNA (vsiRNA) production. We also demonstrate that among 11 TuMV-encoded viral proteins, VPg is the only one that interacts with SGS3. We furthermore present evidence that the expression of VPg alone, independent of viral infection, is sufficient to induce the degradation of SGS3 and its intimate partner RNA-dependent RNA polymerase 6 (RDR6). Moreover, we discover that the VPg-mediated degradation of SGS3 occurs via both the 20S ubiquitin-proteasome and autophagy pathways. Taken together, our data suggest a role for VPg-mediated degradation of SGS3 in suppression of silencing by VPg. IMPORTANCE Potyviruses represent the largest group of known plant viruses and cause significant losses of many agriculturally important crops in the world. In order to establish infection, potyviruses must overcome the host antiviral silencing response. A viral protein called VPg has been shown to play a role in this process, but how it works is unclear. In this paper, we found that the VPg protein of Turnip mosaic virus (TuMV), which is a potyvirus, interacts with a host protein named SGS3, a key protein in the RNA silencing pathway. Moreover, this interaction leads to the degradation of SGS3 and its interacting and functional partner RDR6, which is another essential component of the RNA silencing pathway. We also identified the cellular pathways that are recruited for the VPg-mediated degradation of SGS3. Therefore, this work reveals a possible mechanism by which VPg sabotages host antiviral RNA silencing to promote virus infection.

Characterisation of epitopes on barley mild mosaic virus coat protein recognised by a panel of novel monoclonal antibodies

2005 ◽  
Vol 150 (12) ◽  
pp. 2501-2512 ◽  
Author(s):  
D. Veliceasa ◽  
G. Tauscher ◽  
G. Surányi ◽  
P. B. Kós ◽  
I. Likó ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Coat Protein ◽  
Mosaic Virus ◽  
Mild Mosaic ◽  
Virus Coat Protein ◽  
Mild Mosaic Virus ◽  
Virus Coat

The truth about Pea mild mosaic virus

2014 ◽  
Vol 43 (2) ◽  
pp. 193-196 ◽  
Author(s):  
Z. Perez-Egusquiza ◽  
J. Z. Tang ◽  
L. I. Ward ◽  
J. D. Fletcher
Keyword(s):  
Mosaic Virus ◽  
Mild Mosaic ◽  
Mild Mosaic Virus
Sign in / Sign up

Export Citation Format

Share Document