The Structure and in Vitro Assembly of Southern Bean Mosaic Virus in Relation to that of Other Small Spherical Plant Viruses

2018 ◽  
pp. 123-153
Author(s):  
Michael G. Rossmann
Virology ◽  
1982 ◽  
Vol 118 (1) ◽  
pp. 35-44 ◽  
Author(s):  
J.H. Tremaine ◽  
W.P. Ronald ◽  
E.M. Kelly

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anthony Gobert ◽  
Yifat Quan ◽  
Mathilde Arrivé ◽  
Florent Waltz ◽  
Nathalie Da Silva ◽  
...  

AbstractPlant viruses cause massive crop yield loss worldwide. Most plant viruses are RNA viruses, many of which contain a functional tRNA-like structure. RNase P has the enzymatic activity to catalyze the 5′ maturation of precursor tRNAs. It is also able to cleave tRNA-like structures. However, RNase P enzymes only accumulate in the nucleus, mitochondria, and chloroplasts rather than cytosol where virus replication takes place. Here, we report a biotechnology strategy based on the re-localization of plant protein-only RNase P to the cytosol (CytoRP) to target plant viruses tRNA-like structures and thus hamper virus replication. We demonstrate the cytosol localization of protein-only RNase P in Arabidopsis protoplasts. In addition, we provide in vitro evidences for CytoRP to cleave turnip yellow mosaic virus and oilseed rape mosaic virus. However, we observe varied in vivo results. The possible reasons have been discussed. Overall, the results provided here show the potential of using CytoRP for combating some plant viral diseases.


2015 ◽  
Vol 89 (24) ◽  
pp. 12427-12440 ◽  
Author(s):  
Robyn Roberts ◽  
Jincan Zhang ◽  
Laura K. Mayberry ◽  
Satyanarayana Tatineni ◽  
Karen S. Browning ◽  
...  

ABSTRACTSeveral plant viruses encode elements at the 5′ end of their RNAs, which, unlike most cellular mRNAs, can initiate translation in the absence of a 5′ m7GpppG cap. Here, we describe an exceptionally long (739-nucleotide [nt]) leader sequence in triticum mosaic virus (TriMV), a recently emerged wheat pathogen that belongs to thePotyviridaefamily of positive-strand RNA viruses. We demonstrate that the TriMV 5′ leader drives strong cap-independent translation in both wheat germ extract and oat protoplasts through a novel, noncanonical translation mechanism. Translation preferentially initiates at the 13th start codon within the leader sequence independently of eIF4E but involves eIF4G. We truncated the 5′ leader to a 300-nucleotide sequence that drives cap-independent translation from the 5′ end. We show that within this sequence, translation activity relies on a stem-loop structure identified at nucleotide positions 469 to 490. The disruption of the stem significantly impairs the function of the 5′ untranslated region (UTR) in driving translation and competing against a capped RNA. Additionally, the TriMV 5′ UTR can direct translation from an internal position of a bicistronic mRNA, and unlike cap-driven translation, it is unimpaired when the 5′ end is blocked by a strong hairpin in a monocistronic reporter. However, the disruption of the identified stem structure eliminates such a translational advantage. Our results reveal a potent and uniquely controlled translation enhancer that may provide new insights into mechanisms of plant virus translational regulation.IMPORTANCEMany members of thePotyviridaefamily rely on their 5′ end for translation. Here, we show that the 739-nucleotide-long triticum mosaic virus 5′ leader bears a powerful translation element with features distinct from those described for other plant viruses. Despite the presence of 12 AUG start codons within the TriMV 5′ UTR, translation initiates primarily at the 13th AUG codon. The TriMV 5′ UTR is capable of driving cap-independent translationin vitroandin vivo, is independent of eIF4E, and can drive internal translation initiation. A hairpin structure at nucleotide positions 469 to 490 is required for the cap-independent translation and internal translation initiation abilities of the element and plays a role in the ability of the TriMV UTR to compete against a capped RNAin vitro. Our results reveal a novel translation enhancer that may provide new insights into the large diversity of plant virus translation mechanisms.


1966 ◽  
Vol 44 (6) ◽  
pp. 821-826 ◽  
Author(s):  
J. R. Edwardson ◽  
D. E. Purcifull ◽  
R. G. Christie

Particles within lesions of leaf tissue infected with either tobacco necrosis virus (TNV) or southern bean mosaic virus (SBMV) were compared with particles in embedded pellets of purified preparations of these viruses by an examination of thin sections. The mode of the diameters of particles in tissues and pellets was 20.5 mµ.It is assumed that the particles in infected tissues are virus particles on the basis of their similarities in size, shape, and arrangement with the particles in purified preparations.


Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1162-1162 ◽  
Author(s):  
E. Segundo ◽  
F. M. Gil-Salas ◽  
D. Janssen ◽  
G. Martin ◽  
I. M. Cuadrado ◽  
...  

Common bean (Phaseolus vulgaris L.) is grown on approximately 1,500 ha in commercial greenhouses and is of major economic importance in the Souss-Massa Region, Agadir, Morocco. Since October 2003, symptoms resembling a viral disease, consisting of pod mosaic and distortion and mild to severe mosaic in leaves, have been observed on bean plants in several greenhouses. Mechanical inoculation with symptomatic leaf extracts produced necrotic local lesions on P. vulgaris ‘Pinto’ and systemic symptoms similar to those observed in the naturally infected bean plants P. vulgaris ‘Donna’ (five plants per cultivar). Inoculated and naturally infected samples reacted positively using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to Southern bean mosaic virus (SBMV) (DSMZ, Braunschweig, Germany), a member of the Sobemovirus genus that is transmitted by contact, soil, beetles, and seeds (1). Virions purified from a naturally infected ‘Donna’ plant contained a 30-kDa polypeptide that reacted positively using sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis with SBMV antiserum (DSMZ). Reverse transcription-polymerase chain reaction amplification with SMBV primers as described by Verhoeven et al. (2) produced an expected 870-bp band. The amplicon was cloned, sequenced (GenBank Accession No. AJ748276), and compared to those isolates available in GenBank and had a nucleotide sequence identity of 87% and a derived amino acid sequence identity of 95% with an SBMV isolate from Spain (2). During a survey in different areas of the Souss-Massa Region, 20 symptomatic leaf and pod samples were randomly collected from 12 greenhouses (50 ha) where significant commercial losses were suffered because of this virus disease, and all samples were positive using DAS-ELISA for SBMV. To our knowledge, this is the first report of SBMV in Morocco. References: (1) J. H. Tremaine and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983. (2) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 109:935, 2003.


2012 ◽  
Vol 93 (5) ◽  
pp. 1120-1126 ◽  
Author(s):  
Xiaoyun Lu ◽  
Jeremy R. Thompson ◽  
Keith L. Perry

An important property of some spherical plant viruses is their ability to reassemble in vitro from native capsid protein (CP) and RNA into infectious virus-like particles (VLPs). Virions of cucumber mosaic virus (CMV) are stabilized by protein–RNA interactions and the nucleic acid is essential for assembly. This study demonstrated that VLPs will form in the presence of both ssDNA and dsDNA oligonucleotides, and with a lower size limit of 20 nt. Based on urea disruption assays, assembled VLPs from CMV CP and RNA (termed ReCMV) exhibited a level of stability similar to that of virions purified from plants, whilst VLPs from CMV CP and a 20mer exhibited comparable or greater stability. Fluorescent labelling of VLPs was achieved by the encapsidation of an Alexa Fluor 488-labelled 45mer oligonucleotide (ReCMV-Alexa488-45) and confirmed by transmission electron and confocal microscopy. Using ssDNA as a nucleating factor, encapsidation of fluorescently labelled streptavidin (53 kDa) conjugated to a biotinylated oligonucleotide was observed. The biological activity and stability of ReCMV and ReCMV-Alexa488-45 was confirmed in infectivity assays and insect vector feeding assays. This work demonstrates the utility of CMV CP as a protein cage for use in the growing repertoire of nanotechnological applications.


1984 ◽  
Vol 62 (11) ◽  
pp. 2336-2339 ◽  
Author(s):  
Richard Hogue ◽  
Alain Asselin

The intermediates of disassembly of the U1, U4, U6, and U7 strains of tobacco mosaic virus (TMV) induced by alkali and urea were directly analysed by electrophoresis in composite polyacrylamide (2.0 to 2.5% (w/v)) – agarose (0.5% (w/v)) gels, using a discontinuous buffer system with Tris, borate, EDTA, and sodium chloride (pH 8.3). The results show no difference between the disassembly patterns of the four strains. In the case of alkaline stripping, two new major partially stripped virus (PSV) particles (PSV 5a and PSV 5c) and several minor intermediates were characterized. The overall results indicate that polyacrylamide–agarose gel electrophoresis is superior to agarose gel electrophoresis and to sucrose density gradient ccntrifugation for the analytical separation of PSVs. Polyacrylamide–agarose gel electrophoresis is thus a rather simple, rapid, and efficient method of studying in vitro disassembly of plant viruses.


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