Members of the family Secoviridae are non-enveloped plant viruses with mono- or bipartite linear positive-sense ssRNA genomes with a combined genome of 9 to 13.7 kb and icosahedral particles 25-30 nm in diameter. They are related to picornaviruses and are members of the order Picornavirales. Genera in the family are distinguished by the host range, vector, genomic features and phylogeny of the member viruses. Most members infect dicotyledonous plants, and many cause serious disease epidemics. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) report on the family Secoviridae, which is available at ictv.global/report/secoviridae.
Our goal was to target silencing of the Plum pox virus coat protein (PPV CP) gene independently expressed in plants. Clone C-2 is a transgenic plum expressing CP. We introduced and verified, in planta, the effects of the inverse repeat of CP sequence split by a hairpin (IRSH) that was characterized in the HoneySweet plum. The IRSH construct was driven by two CaMV35S promoter sequences flanking the CP sequence and had been introduced into C1738 plum. To determine if this structure was enough to induce silencing, cross-hybridization was made with the C1738 clone and the CP expressing but PPV-susceptible C2 clone. In total, 4 out of 63 clones were silenced. While introduction of the IRSH is reduced due to the heterozygous character in C1738 plum, the silencing induced by the IRSH PPV CP is robust. Extensive studies, in greenhouse containment, demonstrated that the genetic resource of C1738 clone can silence the CP production. In addition, these were verified through the virus transgene pyramiding in the BO70146 BlueByrd cv. plum that successfully produced resistant BlueByrd BO70146 × C1738 (HybC1738) hybrid plums.
- MeSH
- biotechnologie metody MeSH
- genetické inženýrství metody MeSH
- odolnost vůči nemocem * MeSH
- slivoň genetika virologie MeSH
- transgeny MeSH
- umlčování genů * MeSH
- virové plášťové proteiny genetika metabolismus MeSH
- virus šarky švestky genetika patogenita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Two novel dsDNA bacteriophages named Pectobacterium virus CB251 (PcCB251) and Pectobacterium virus CB7V (PcCB7V) targeting plant pathogen Pectobacterium parmentieri have been isolated and sequenced. The PcCB251 genome consists of 40,557 bp with G+C content of 48.6% and contains 47 predicted genes on a single strand. The phage is classified in genus Berlinvirus, family Autographiviridae. The PcCB7V phage has a circular dsDNA genome of 146,054 bp with G+C content of 50.4% and contains 269 predicted protein genes on both strands and 13 tRNA genes. The PcCB7V phage can be classified in genus Certrevirus, subfamily Vequintavirinae. Both novel bacteriophages have narrow host ranges, but they extend the list of candidates for phage-based control of pectolytic bacteria causing soft rot disease of potato.
High-throughput sequencing technologies were used to identify plant viruses in cereal samples surveyed from 2012 to 2017. Fifteen genome sequences of a tenuivirus infecting wheat, oats, and spelt in Estonia, Norway, and Sweden were identified and characterized by their distances to other tenuivirus sequences. Like most tenuiviruses, the genome of this tenuivirus contains four genomic segments. The isolates found from different countries shared at least 92% nucleotide sequence identity at the genome level. The planthopper Javesella pellucida was identified as a vector of the virus. Laboratory transmission tests using this vector indicated that wheat, oats, barley, rye, and triticale, but none of the tested pasture grass species (Alopecurus pratensis, Dactylis glomerata, Festuca rubra, Lolium multiflorum, Phleum pratense, and Poa pratensis), are susceptible. Taking into account the vector and host range data, the tenuivirus we have found most probably represents European wheat striate mosaic virus first identified about 60 years ago. Interestingly, whereas we were not able to infect any of the tested cereal species mechanically, Nicotiana benthamiana was infected via mechanical inoculation in laboratory conditions, displaying symptoms of yellow spots and vein clearing evolving into necrosis, eventually leading to plant death. Surprisingly, one of the virus genome segments (RNA2) encoding both a putative host systemic movement enhancer protein and a putative vector transmission factor was not detected in N. benthamiana after several passages even though systemic infection was observed, raising fundamental questions about the role of this segment in the systemic spread in several hosts.
- MeSH
- genom virový * genetika MeSH
- Hemiptera virologie MeSH
- jedlá semena virologie MeSH
- nemoci rostlin virologie MeSH
- rostlinné viry * genetika MeSH
- viry mozaiky * genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Norsko MeSH
- Švédsko MeSH
Screening of apple samples using a high-throughput sequencing (HTS) approach led to the discovery of a novel virus, tentatively named "Malus domestica virus A" (MdoVA). Its genomic organisation and phylogenetic relationship showed relatedness to viruses of the genus Velarivirus in the family Closteroviridae. It is not clear whether MdoVA has any impact on its host, as the analysed apple tree contained other viruses and a viroid.
Tobacco (Nicotiana tabacum) pollen is a well-suited model for studying many fundamental biological processes owing to its well-defined and distinct development stages. It is also one of the major agents involved in the transmission of infectious viroids, which is the primary mechanism of viroid pathogenicity in plants. However, some viroids are non-transmissible and may be possibly degraded or eliminated during the gradual process of pollen development maturation. The molecular details behind the response of developing pollen against the apple fruit crinkle viroid (AFCVd) infection and viroid eradication is largely unknown. In this study, we performed an integrative analysis of the transcriptome and proteome profiles to disentangle the molecular cascade of events governing the three pollen development stages: early bicellular pollen (stage 3, S3), late bicellular pollen (stage 5, S5), and 6 h-pollen tube (PT6). The integrated analysis delivered the molecular portraits of the developing pollen against AFCVd infection, including mechanistic insights into the viroid eradication during the last steps of pollen development. The isobaric tags for label-free relative quantification (iTRAQ) with digital gene expression (DGE) experiments led us to reliably identify subsets of 5321, 5286, and 6923 proteins and 64,033, 60,597, and 46,640 expressed genes in S3, S5, and PT6, respectively. In these subsets, 2234, 2108 proteins and 9207 and 14,065 mRNAs were differentially expressed in pairwise comparisons of three stages S5 vs. S3 and PT6 vs. S5 of control pollen in tobacco. Correlation analysis between the abundance of differentially expressed mRNAs (DEGs) and differentially expressed proteins (DEPs) in pairwise comparisons of three stages of pollen revealed numerous discordant changes in mRNA/protein pairs. Only a modest correlation was observed, indicative of divergent transcription, and its regulation and importance of post-transcriptional events in the determination of the fate of early and late pollen development in tobacco. The functional and enrichment analysis of correlated DEGs/DEPs revealed the activation in pathways involved in carbohydrate metabolism, amino acid metabolism, lipid metabolism, and cofactor as well as vitamin metabolism, which points to the importance of these metabolic pathways in pollen development. Furthermore, the detailed picture of AFCVd-infected correlated DEGs/DEPs was obtained in pairwise comparisons of three stages of infected pollen. The AFCVd infection caused the modulation of several genes involved in protein degradation, nuclear transport, phytohormone signaling, defense response, and phosphorylation. Intriguingly, we also identified several factors including, DNA-dependent RNA-polymerase, ribosomal protein, Argonaute (AGO) proteins, nucleotide binding proteins, and RNA exonucleases, which may plausibly involve in viroid stabilization and eradication during the last steps of pollen development. The present study provides essential insights into the transcriptional and translational dynamics of tobacco pollen, which further strengthens our understanding of plant-viroid interactions and support for future mechanistic studies directed at delineating the functional role of candidate factors involved in viroid elimination.
The plant genome can produce long non-coding RNAs (lncRNAs), some of which have been identified as important regulators of gene expression. To better understand the response mechanism of rice plants to Rice black-streaked dwarf virus (RBSDV) infection, we performed a comparative transcriptome analysis between the RBSDV-infected and non-infected rice plants. A total of 1342 mRNAs and 22 lncRNAs were identified to be differentially expressed after RBSDV infection. Most differentially expressed transcripts involved in the plant-pathogen interaction pathway were upregulated after RBSDV infection, indicating the activation of rice defense response by RBSDV. A network of differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) was then constructed. In this network, there are 56 plant-pathogen interaction-related DEmRNAs co-expressing with 20 DElncRNAs, suggesting these DElncRNAs and DEmRNAs may play essential roles in rice innate immunity against RBSDV. Moreover, some of the lncRNA-mRNA regulatory relationships were experimentally verified in rice calli by a quick and effective method established in this study. Three DElncRNAs were selected to be tested, and the results indicated that five mRNAs were found to be regulated by them. Together, we give a whole landscape of rice mRNAs and lncRNAs in response to RBSDV infection, and a feasible method to rapidly verify the lncRNA-mRNA regulatory relationship in rice.
- MeSH
- messenger RNA genetika metabolismus MeSH
- nemoci rostlin genetika virologie MeSH
- regulace genové exprese u rostlin * MeSH
- RNA dlouhá nekódující genetika metabolismus MeSH
- RNA rostlin genetika metabolismus MeSH
- rostlinné viry genetika fyziologie MeSH
- stanovení celkové genové exprese MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We present a taxonomic proposal for revision of the family Secoviridae, a taxon of plant viruses in the order Picornavirales. We propose the reorganization of the genus Sadwavirus to create three new subgenera and to update the classification of five existing species. The proposed subgenera are "Satsumavirus" (one species: Satsuma dwarf virus), "Stramovirus" (two species: Strawberry mottle virus and Black raspberry necrosis virus) and "Cholivirus" (two species: Chocolate lily virus A and Dioscorea mosaic associated virus).
- MeSH
- fylogeneze MeSH
- genom virový genetika MeSH
- RNA virová genetika MeSH
- RNA-viry genetika MeSH
- Secoviridae klasifikace genetika MeSH
- Publikační typ
- časopisecké články MeSH
Double-stranded RNA and total RNA purified from sour cherry leaves (Prunus cerasus, cv. Amarelka Chvalkovicka) was analyzed by high-throughput sequencing. BLAST annotation identified contigs with homology to several already known cherry-infecting viruses (prune dwarf virus, prunus necrotic ringspot virus, prunus virus F, little cherry virus 1) as well as contigs with sequences more distantly related to those of members of the family Betaflexiviridae and in particular to prunus virus T of the genus Tepovirus. The full genome sequence of a putative virus (6,847 nucleotides [nt]; GenBank no. MT090966) was assembled and completed at the genome ends. The genome has a typical tepovirus organization, containing three overlapping open reading frames (ORFs), encoding a replication-associated protein, a movement protein and a capsid protein, respectively. Both its genome organization and its phylogenetic relationships show that the virus belongs to the genus Tepovirus, but considering the species demarcation criteria for the family Betaflexiviridae, it appears to represent a novel virus species, and we propose the name "cherry virus T" (ChVT) for this virus.
- MeSH
- Flexiviridae klasifikace genetika izolace a purifikace MeSH
- fylogeneze MeSH
- genom virový * MeSH
- nemoci rostlin virologie MeSH
- otevřené čtecí rámce MeSH
- Prunus avium virologie MeSH
- sekvence nukleotidů MeSH
- sekvenování celého genomu MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- Publikační typ
- časopisecké články MeSH
The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive. In this study, we investigated for the first time the gene expression modulation of selected MED subunits in response to five viroid species (Apple fruit crinkle viroid (AFCVd), Citrus bark cracking viroid (CBCVd), Hop latent viroid (HLVd), Hop stunt viroid (HSVd), and Potato spindle tuber viroid (PSTVd)) in two model plant species (Nicotiana tabacum and N. benthamiana) and a commercially important hop (Humulus lupulus) cultivar. Our results showed a differential expression pattern of MED subunits in response to a viroid infection. The individual plant MED subunits displayed a differential and tailored expression pattern in response to different viroid species, suggesting that the MED expression is viroid- and plant species-dependent. The explicit evidence obtained from our results warrants further investigation into the association of the MED subunit with symptom development. Together, we provide a comprehensive portrait of MED subunit expression in response to viroid infection and a plausible involvement of MED subunits in fine-tuning transcriptional reprogramming in response to viroid infection, suggesting them as a potential candidate for rewiring the defense response network in plants against pathogens.
- MeSH
- druhová specificita MeSH
- Humulus genetika virologie MeSH
- listy rostlin genetika mikrobiologie MeSH
- mediátorový komplex genetika MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné proteiny genetika MeSH
- rostlinné viry MeSH
- stanovení celkové genové exprese MeSH
- tabák genetika virologie MeSH
- viroidy genetika patogenita MeSH
- Publikační typ
- časopisecké články MeSH
