186 research outputs found

    Viromes of Ten Alfalfa Plants in Australia Reveal Diverse Known Viruses and a Novel RNA Virus

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    Alfalfa plants in the field can display a range of virus-like symptoms, especially when grown over many years for seed production. Most known alfalfa viruses have RNA genomes, some of which can be detected using diagnostic assays, but many viruses of alfalfa are not well characterized. This study aims to identify the RNA and DNA virus complexes associated with alfalfa plants in Australia. To maximize the detection of RNA viruses, we purified double-stranded RNA (dsRNA) for high throughput sequencing and characterized the viromes of ten alfalfa samples that showed diverse virus-like symptoms. Using Illumina sequencing of tagged cDNA libraries from immune-captured dsRNA, we identified sequences of the single-stranded RNA viruses, alfalfa mosaic virus (AMV), bean leafroll virus, a new emaravirus tentatively named alfalfa ringspot-associated virus, and persistent dsRNA viruses belonging to the families Amalgaviridae and Partitiviridae. Furthermore, rolling circle amplification and restriction enzyme digestion revealed the complete genome of chickpea chlorosis Australia virus, a mastrevirus (family Geminiviridae) previously reported only from chickpea and French bean that was 97% identical to the chickpea isolate. The sequence data also enabled the assembly of the first complete genome (RNAs 1–3) of an Australian AMV isolate from alfalfa

    Genetic Diversity Among Banana streak virus Isolates from Australia

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    Banana streak virus (BSV) is an important pathogen of bananas and plantains (Musa spp.) throughout the world. We have cloned and sequenced part of the genomes of four isolates of BSV from Australia, designated BSV-RD, BSV-Cav, BSV-Mys, and BSV-GF. These isolates originated from banana cvs. Red Dacca, Williams, Mysore, and Goldfinger, respectively. All clones contained a sequence covering part of open reading frame III and the intergenic region of the badnavirus genome. The sequences were compared with those of other badnaviruses, including BSV-Onne, a previously characterized isolate from Nigeria. The BSV-RD sequence was virtually identical to that of BSV-Onne, differing by only two nucleotides over 1,292 bp. However, BSV-Cav, -Mys, and -GF were divergent in nucleotide sequence. Phylogenetic analyses using conserved sequences in the ribonuclease H domain revealed that all BSV isolates were more closely related to each other than to any other badnavirus. BSV-Cav was most closely related to BSV-Onne, and there was 95.1% identity between the two amino acid sequences. Other relationships between the BSV isolates were less similar, with sequence identities ranging from 66.4 to 78.2%, which is a magnitude comparable to the distance between some of the recognized badnavirus species. Immunocapture-polymerase chain reaction assays have been developed, allowing specific detection and differentiation of the four isolates of BSV

    Συνελίξεις κατανομών με βαριά ουρά

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    223 σ.Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Εφαρμοσμένες Μαθηματικές Επιστήμες”Στην παρούσα εργασία αντικείμενο αποτελούν οι συνελίξεις των κατανομών με βαριά ουρά, και πιο συγκεκριμένα οι υποεκθετικές κατανομές. Οι υποεκθετικές κατανομές είναι μια υποκατηγορία των κατανομών με βαριά ουρά και έχουν εφαρμογές σε πολλά επιστημονικά αντικείμενα. Στηρίζονται στην ιδέα πως ένα άθροισμα τυχαίων μεταβλητών μπορεί να υπερβεί κάποιο μεγάλο φράγμα μόνο όταν μια από αυτές τις μεταβλητές υπερβεί αυτό το φράγμα.Σε αυτή την εργασία θα ασχοληθούμε με την εφαρμογή των υποεκθετικών κατανομών στον αναλογισμό και πιο συγκεκριμένα στη θεωρία χρεοκοπίας. Στην προσπάθεια μας να ορίσουμε μαθηματικά την θεωρία χρεοκοπίας χρησιμοποιούμε τους τυχαίους περιπάτους . Σκοπός της παρούσας εργασίας είναι να δείξουμε πως συμπεριφέρεται η πιθανότητα χρεοκοπίας κάτω από την υπόθεση των υποεκθετικών κατανομών και πώς συμπεριφέρεται όταν δεν ισχύει η υπόθεση των υποεκθετικών κατανομών.In this work, item are convolutions of heavy tailed distributions , and more specifically subexponencial distributions . Subexponencial distributions are a subclass of distributions with heavy tail and have applications in many scientific fields . Based on the idea that a sum of random variables can exceed a big bound only when one of these variables exceeds this bound.In this paper we discuss the application of subexponential distributions in actuarial science and in particular in ruin theory . In our effort to define ruin theory we use random walks. The purpose of this paper is the behavior of ruin probability under the assumption of subexponential distributions and how it behaves when it does not apply the case of subexponential distributions.Σωτήριος Ι. Λοσίδη

    Effects of Some Chinese Strains of Peanut Stripe Virus (PStV) on Groundnut Cultivars and Other Plants

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    Seed transmission frequency and pod losses of groundnuts (Arachis hypogaea) due to peanut stripe virus isolates are reported from China. Five isolates were collected in Wuhan (PStV-W1, W2, N), Guangzhou (PStV-G) and Tansan (PStV-T). These were divided into 3 groups on the basis of symptoms in various groundnut genotypes. Isolates in group 1, which produced mild mottling, were widely distributed. PStV-W1 caused a 1.4-6.4% reduction in plant height, and G, 9.2-16.3%. Losses in pod yields due to these isolates were 20.8-36.6 and 29.8-55%, respectively. PStV-W1 was transmitted to 20.9% and PStV-G to 6.1% of seed of cv Zhonghua No.3. All five isolates were transmitted by Aphis craccivora

    Detection and profiling of circular RNAs in uninfected and maize Iranian mosaic virus-infected maize

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    Circular RNAs (circRNAs) are covalently closed non-coding RNAs that are usually derived from exonic regions of genes, but can also arise from intronic and intergenic regions. Studies of circRNAs in humans, animals and several plant species have shown an altered population of circRNAs in response to abiotic and biotic stress. Recently it was shown that circRNAs also occur in maize, but it is unknown if maize circRNAs are responsive to stress. Maize Iranian mosaic virus (MIMV, genus Nucleorhabdovirus, family Rhabdoviridae) causes an economically important disease in maize and other gramineous crops in Iran. In this study, we used data from RNA-Seq of MIMV-infected maize and uninfected controls to identify differentially expressed circRNAs. Such circRNAs were confirmed by two-dimensional polyacrylamide gel electrophoresis, northern blot, RT-qPCR and sequencing. A total of 1443 circRNAs were identified in MIMV-infected maize and 1165 circRNAs in uninfected maize. Two hundred and one circRNAs were in common between MIMV-infected and uninfected samples. Of these, 155 circRNAs were up-regulated and 5 down-regulated in MIMV infected plants, compared to the uninfected control. This study for the first time identified and profiled circRNA expression in maize in response to virus infection. Moreover, we predict that 33 circRNAs may bind 23 maize miRNAs, possibly affecting plant metabolism and development. Our data suggest a role for circRNAs in plant cell regulation and response to biotic stress such as virus infection, and give new insights into the complexity of plant-microbe interactions

    Widespread Endogenization of Genome Sequences of Non-Retroviral RNA Viruses into Plant Genomes

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    Non-retroviral RNA virus sequences (NRVSs) have been found in the chromosomes of vertebrates and fungi, but not plants. Here we report similarly endogenized NRVSs derived from plus-, negative-, and double-stranded RNA viruses in plant chromosomes. These sequences were found by searching public genomic sequence databases, and, importantly, most NRVSs were subsequently detected by direct molecular analyses of plant DNAs. The most widespread NRVSs were related to the coat protein (CP) genes of the family Partitiviridae which have bisegmented dsRNA genomes, and included plant- and fungus-infecting members. The CP of a novel fungal virus (Rosellinia necatrix partitivirus 2, RnPV2) had the greatest sequence similarity to Arabidopsis thaliana ILR2, which is thought to regulate the activities of the phytohormone auxin, indole-3-acetic acid (IAA). Furthermore, partitivirus CP-like sequences much more closely related to plant partitiviruses than to RnPV2 were identified in a wide range of plant species. In addition, the nucleocapsid protein genes of cytorhabdoviruses and varicosaviruses were found in species of over 9 plant families, including Brassicaceae and Solanaceae. A replicase-like sequence of a betaflexivirus was identified in the cucumber genome. The pattern of occurrence of NRVSs and the phylogenetic analyses of NRVSs and related viruses indicate that multiple independent integrations into many plant lineages may have occurred. For example, one of the NRVSs was retained in Ar. thaliana but not in Ar. lyrata or other related Camelina species, whereas another NRVS displayed the reverse pattern. Our study has shown that single- and double-stranded RNA viral sequences are widespread in plant genomes, and shows the potential of genome integrated NRVSs to contribute to resolve unclear phylogenetic relationships of plant species

    Filovirus RefSeq Entries: Evaluation and Selection of Filovirus Type Variants, Type Sequences, and Names

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    Sequence determination of complete or coding-complete genomes of viruses is becoming common practice for supporting the work of epidemiologists, ecologists, virologists, and taxonomists. Sequencing duration and costs are rapidly decreasing, sequencing hardware is under modification for use by non-experts, and software is constantly being improved to simplify sequence data management and analysis. Thus, analysis of virus disease outbreaks on the molecular level is now feasible, including characterization of the evolution of individual virus populations in single patients over time. The increasing accumulation of sequencing data creates a management problem for the curators of commonly used sequence databases and an entry retrieval problem for end users. Therefore, utilizing the data to their fullest potential will require setting nomenclature and annotation standards for virus isolates and associated genomic sequences. The National Center for Biotechnology Information’s (NCBI’s) RefSeq is a non-redundant, curated database for reference (or type) nucleotide sequence records that supplies source data to numerous other databases. Building on recently proposed templates for filovirus variant naming [ ()////-], we report consensus decisions from a majority of past and currently active filovirus experts on the eight filovirus type variants and isolates to be represented in RefSeq, their final designations, and their associated sequences

    Taxonomy of the order Mononegavirales: update 2016

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    In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV)

    2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

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    Correction to: 2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales. Archives of Virology (2021) 166:3567–3579. https://doi.org/10.1007/s00705-021-05266-wIn March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through Laulima Government Solutions, LLC prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC under Contract No. HHSN272201800013C. This work was also supported in part with federal funds from the National Cancer Institute (NCI), National Institutes of Health (NIH), under Contract No. 75N91019D00024, Task Order No. 75N91019F00130 to I.C., who was supported by the Clinical Monitoring Research Program Directorate, Frederick National Lab for Cancer Research. This work was also funded in part by Contract No. HSHQDC-15-C-00064 awarded by DHS S&T for the management and operation of The National Biodefense Analysis and Countermeasures Center, a federally funded research and development center operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowledges partial support from the Special Research Initiative of Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University, and the National Institute of Food and Agriculture, US Department of Agriculture, Hatch Project 1021494. Part of this work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001030), the UK Medical Research Council (FC001030), and the Wellcome Trust (FC001030).S

    Taxonomy of the order Mononegavirales : update 2016

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    In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV)
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