scholarly journals Apple latent spherical virus structure with stable capsid frame supports quasi-stable protrusions expediting genome release

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Hisashi Naitow ◽  
Tasuku Hamaguchi ◽  
Saori Maki-Yonekura ◽  
Masamichi Isogai ◽  
Nobuyuki Yoshikawa ◽  
...  
Keyword(s):  
Viral Genome ◽  
Plant Virus ◽  
Molecular Mechanisms ◽  
Low Frequency ◽  
Plant Viruses ◽  
Virus Structure ◽  
Apple Latent Spherical Virus ◽  
Cryo Electron Microscopy ◽  
Rigid Frame ◽  
Emission Beam

AbstractPicorna-like plant viruses are non-enveloped RNA spherical viruses of ~30 nm. Part of the survival of these viruses depends on their capsid being stable enough to harbour the viral genome and yet malleable enough to allow its release. However, molecular mechanisms remain obscure. Here, we report a structure of a picorna-like plant virus, apple latent spherical virus, at 2.87 Å resolution by single-particle cryo-electron microscopy (cryo-EM) with a cold-field emission beam. The cryo-EM map reveals a unique structure composed of three capsid proteins Vp25, Vp20, and Vp24. Strikingly Vp25 has a long N-terminal extension, which substantially stabilises the capsid frame of Vp25 and Vp20 subunits. Cryo-EM images also resolve RNA genome leaking from a pentameric protrusion of Vp24 subunits. The structures and observations suggest that genome release occurs through occasional opening of the Vp24 subunits, possibly suppressed to a low frequency by the rigid frame of the other subunits.

Identification of Plant Virus Movement-Host Protein Interactions

2001 ◽  
Vol 56 (9-10) ◽  
pp. 669-679 ◽  
Author(s):  
Jan-Wolfhard Kellmann
Keyword(s):  
Protein Interactions ◽  
Plant Virus ◽  
Molecular Mechanisms ◽  
Plant Viruses ◽  
Host Protein ◽  
Virus Movement ◽  
Plant Tissues ◽  
Host Proteins ◽  
Movement Proteins ◽  
Systemic Spread

Abstract After the discovery of ‘movement proteins’ as a peculiarity of plant viruses and with the help of novel methods for the detection and isolation of interacting host proteins new insights have been obtained to understand the mechanisms of virus movement in plant tissues. Rapid progress in studying the molecular mechanisms of systemic spread of plant infecting viruses revealed an interrelation between virus movement and macromolecular trafficking in plant tissues. This article summarizes current explorations on plant virus movement proteins (MPs) and introduces the state of the art in the identification and isolation of MP interacting host proteins.

scholarly journals Cryo–electron microscopy structure of the antidiuretic hormone arginine-vasopressin V2 receptor signaling complex

2021 ◽  
Vol 7 (21) ◽  
pp. eabg5628
Author(s):  
Julien Bous ◽  
Hélène Orcel ◽  
Nicolas Floquet ◽  
Cédric Leyrat ◽  
Joséphine Lai-Kee-Him ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antidiuretic Hormone ◽  
Arginine Vasopressin ◽  
Molecular Mechanisms ◽  
Particle Analysis ◽  
Resonance Spectroscopy ◽  
Gpcr Signaling ◽  
Signaling Complex ◽  
Cryo Electron Microscopy ◽  
V2 Receptor

The antidiuretic hormone arginine-vasopressin (AVP) forms a signaling complex with the V2 receptor (V2R) and the Gs protein, promoting kidney water reabsorption. Molecular mechanisms underlying activation of this critical G protein–coupled receptor (GPCR) signaling system are still unknown. To fill this gap of knowledge, we report here the cryo–electron microscopy structure of the AVP-V2R-Gs complex. Single-particle analysis revealed the presence of three different states. The two best maps were combined with computational and nuclear magnetic resonance spectroscopy constraints to reconstruct two structures of the ternary complex. These structures differ in AVP and Gs binding modes. They reveal an original receptor-Gs interface in which the Gαs subunit penetrates deep into the active V2R. The structures help to explain how V2R R137H or R137L/C variants can lead to two severe genetic diseases. Our study provides important structural insights into the function of this clinically relevant GPCR signaling complex.

scholarly journals Softening of Processed Plant Virus Infected Cucumis sativus Fruits

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1451
Author(s):  
Anne-Katrin Kersten ◽  
Sabrina Scharf ◽  
Martina Bandte ◽  
Peer Martin ◽  
Peter Meurer ◽  
...  
Keyword(s):  
Cucumis Sativus ◽  
Plant Virus ◽  
Plant Viruses ◽  
Economic Losses ◽  
Symptom Expression ◽  
Considerable Influence ◽  
Mechanical Inoculation ◽  
Morphological Alterations ◽  
Texture Properties ◽  
Textural Changes

Texture softening of pickled cucumbers does not meet consumers’ quality expectations and leads to economic losses. The factor(s) triggering this phenomenon is still unknown. We investigated the importance of plant viruses such as Cucumber green mottle mosaic tobamovirus (CGMMV) and Zucchini yellow mosaic potyvirus (ZYMV) in the context of softening of pickles. Cucumber plants (Cucumis sativus) were infected by mechanical inoculation, grown under greenhouse conditions and tested positive for the viral infection by ELISA. The severity of virus infection was reflected in yield and symptom expression. Histological and morphological alterations were observed. All fruits were pasteurized, separately stored in jars and subjected to texture measurements after four, six and 12 months. CGMMV-infections were asymptomatic or caused mild symptoms on leaves and fruit, and texture quality was comparable to control. At the same time, fruits of ZYMV-infected plants showed severe symptoms like deformations and discoloration, as well as a reduction in firmness and crunchiness after pasteurization. In addition, histological alterations were detected in such fruits, possibly causing textural changes. We conclude that plant viruses could have a considerable influence on the firmness and crunchiness of pickled cucumbers after pasteurization. It is possible that the severity of symptom expression has an influence on texture properties.

scholarly journals Novel Functional Genomics Approaches: A Promising Future in the Combat Against Plant Viruses

2016 ◽  
Vol 106 (10) ◽  
pp. 1231-1239 ◽  
Author(s):  
Vincent N. Fondong ◽  
Ugrappa Nagalakshmi ◽  
Savithramma P. Dinesh-Kumar
Keyword(s):  
Functional Genomics ◽  
Plant Virus ◽  
Reverse Genetics ◽  
Plant Viruses ◽  
Micro Rna ◽  
Viral Genomes ◽  
Virus Control ◽  
Local Lesions ◽  
Short Palindromic Repeat ◽  
Interfering Rna

Advances in functional genomics and genome editing approaches have provided new opportunities and potential to accelerate plant virus control efforts through modification of host and viral genomes in a precise and predictable manner. Here, we discuss application of RNA-based technologies, including artificial micro RNA, transacting small interfering RNA, and Cas9 (clustered regularly interspaced short palindromic repeat–associated protein 9), which are currently being successfully deployed in generating virus-resistant plants. We further discuss the reverse genetics approach, targeting induced local lesions in genomes (TILLING) and its variant, known as EcoTILLING, that are used in the identification of plant virus recessive resistance gene alleles. In addition to describing specific applications of these technologies in plant virus control, this review discusses their advantages and limitations.

scholarly journals A Four-Partner Plant–Virus Interaction: Enemies Can Also Come from Within

2010 ◽  
Vol 23 (11) ◽  
pp. 1394-1402 ◽  
Author(s):  
Marie-Line Iskra-Caruana ◽  
Franc-Christophe Baurens ◽  
Philippe Gayral ◽  
Matthieu Chabannes
Keyword(s):  
Viral Genome ◽  
Plant Viruses ◽  
Plant Genome ◽  
Interspecific Crosses ◽  
Streak Virus ◽  
Alternative Source ◽  
Remarkable Feature ◽  
Tropical Crops ◽  
Causative Agents ◽  
Partner Interaction

Plant viruses are disseminated by either vertical (vegetative multiplication or sexual reproduction) or horizontal (vector-mediated) propagation. Plant pararetroviruses—members of the Caulimoviridae family—have developed an alternative strategy for vertical propagation via integration within the host plant genome, although integration is not required for viral replication. Integrated endogenous pararetrovirus (EPRV) sequences have undergone extensive viral genome rearrangements and contain more than one copy of the viral genome. Furthermore, EPRV can become infectious upon spontaneous escape of active virus following stresses such as wounding, tissue culture, or interspecific crosses. Such infectious EPRV are of great importance, not only in terms of their ability to precipitate epidemic outbreaks but also because of their effect on breeding of numerous plant genomes in temperate and tropical crops. This is especially true for banana, a crop susceptible to banana streak viruses, the causative agents of banana streak disease. Thus, the classical three-component banana–Banana streak virus (BSV)–mealybug pathosystem can be expanded to include endogenous BSV as an alternative source of active virions. The BSV-banana pathosystem is one of only three pathosystems known to date to harbor this remarkable feature, and the present review focuses exclusively on it to illustrate this four-partner interaction.

The landscape of translational stall sites in bacteria revealed by monosome and disome profiling

RNA ◽  
2021 ◽  
pp. rna.078188.120
Author(s):  
Tomoya Fujita ◽  
Takeshi Yokoyama ◽  
Mikako Shirouzu ◽  
Hideki Taguchi ◽  
Takuhiro Ito ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Frequency ◽  
Ribosome Profiling ◽  
Reporter Assay ◽  
Ribosome Stalling ◽  
Peptidyl Transfer ◽  
Cryo Electron Microscopy ◽  
Nascent Chain ◽  
Biochemical Validation ◽  
Trna Sequencing

Ribosome pauses are associated with various cotranslational events and determine the fate of mRNAs and proteins. Thus, the identification of precise pause sites across the transcriptome is desirable; however, the landscape of ribosome pauses in bacteria remains ambiguous. Here, we harness monosome and disome (or collided ribosome) profiling strategies to survey ribosome pause sites in Escherichia coli. Compared to eukaryotes, ribosome collisions in bacteria showed remarkable differences: a low frequency of disomes at stop codons, collisions occurring immediately after 70S assembly on start codons, and shorter queues of ribosomes trailing upstream. The pause sites corresponded with the biochemical validation by integrated nascent chain profiling (iNP) to detect polypeptidyl-tRNA, an elongation intermediate. Moreover, the subset of those sites showed puromycin resistance, presenting slow peptidyl transfer. Among the identified sites, the ribosome pause at Asn586 of ycbZ was validated by biochemical reporter assay, tRNA sequencing (tRNA-Seq), and cryo-electron microscopy (cryo-EM) experiments. Our results provide a useful resource for ribosome stalling sites in bacteria

scholarly journals Barley yellow dwarf virus-GAV-derived vsiRNAs are involved in the production of wheat leaf yellowing symptoms by targeting chlorophyll synthase

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Chuan Shen ◽  
Caiyan Wei ◽  
Jingyuan Li ◽  
Xudong Zhang ◽  
Qinrong Zhong ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Barley Yellow Dwarf Virus ◽  
Plant Viruses ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Small Rna Sequencing ◽  
Symptom Development ◽  
Barley Yellow Dwarf ◽  
Leaf Yellowing ◽  
Yellow Dwarf Virus

Abstract Background Wheat yellow dwarf virus disease is infected by barley yellow dwarf virus (BYDV), which causes leaf yellowing and dwarfing symptoms in wheat, thereby posing a serious threat to China's food production. The infection of plant viruses can produce large numbers of vsiRNAs, which can target host transcripts and cause symptom development. However, few studies have been conducted to explore the role played by vsiRNAs in the interaction between BYDV-GAV and host wheat plants. Methods In this study, small RNA sequencing was conducted to profile vsiRNAs in BYDV-GAV-infected wheat plants. The putative targets of vsiRNAs were predicted by the bioinformatics software psRNATarget. RT-qPCR and VIGS were employed to identify the function of selected target transcripts. To confirm the interaction between vsiRNA and the target, 5′ RACE was performed to analyze the specific cleavage sites. Results From the sequencing data, we obtained a total of 11,384 detected vsiRNAs. The length distribution of these vsiRNAs was mostly 21 and 22 nt, and an A/U bias was observed at the 5′ terminus. We also observed that the production region of vsiRNAs had no strand polarity. The vsiRNAs were predicted to target 23,719 wheat transcripts. GO and KEGG enrichment analysis demonstrated that these targets were mostly involved in cell components, catalytic activity and plant-pathogen interactions. The results of RT-qPCR analysis showed that most chloroplast-related genes were downregulated in BYDV-GAV-infected wheat plants. Silencing of a chlorophyll synthase gene caused leaf yellowing that was similar to the symptoms exhibited by BYDV-GAV-inoculated wheat plants. A vsiRNA from an overlapping region of BYDV-GAV MP and CP was observed to target chlorophyll synthase for gene silencing. Next, 5′ RACE validated that vsiRNA8856 could cleave the chlorophyll synthase transcript in a sequence-specific manner. Conclusions This report is the first to demonstrate that BYDV-GAV-derived vsiRNAs can target wheat transcripts for symptom development, and the results of this study help to elucidate the molecular mechanisms underlying leaf yellowing after viral infection.

scholarly journals Recent Advances in the Use of Plant Virus-Like Particles as Vaccines

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 270 ◽  
Author(s):  
Ina Balke ◽  
Andris Zeltins
Keyword(s):  
Plant Virus ◽  
Plant Viruses ◽  
Therapeutic Vaccines ◽  
Virus Like Particles ◽  
Wide Range ◽  
Central Elements ◽  
Different Types ◽  
Anticancer Vaccines ◽  
Effective Public Health ◽  
Near Future

Vaccination is one of the most effective public health interventions of the 20th century. All vaccines can be classified into different types, such as vaccines against infectious diseases, anticancer vaccines and vaccines against autoimmune diseases. In recent decades, recombinant technologies have enabled the design of experimental vaccines against a wide range of diseases using plant viruses and virus-like particles as central elements to stimulate protective and long-lasting immune responses. The analysis of recent publications shows that at least 97 experimental vaccines have been constructed based on plant viruses, including 71 vaccines against infectious agents, 16 anticancer vaccines and 10 therapeutic vaccines against autoimmune disorders. Several plant viruses have already been used for the development of vaccine platforms and have been tested in human and veterinary studies, suggesting that plant virus-based vaccines will be introduced into clinical and veterinary practice in the near future.

Virus-Dependent and -Independent Responses of Sitobion avenae (Homoptera: Aphididae) Feeding on Wheat Infected by Transmitted and Nontransmitted Viruses at Transcriptomic Level

2019 ◽  
Vol 112 (5) ◽  
pp. 2067-2076
Author(s):  
Dandan Li ◽  
Dan Su ◽  
Zeqian Tong ◽  
Chi Zhang ◽  
Gaisheng Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Barley Yellow Dwarf Virus ◽  
Plant Viruses ◽  
Sitobion Avenae ◽  
Differentially Expressed ◽  
Dwarf Virus ◽  
Illumina Hiseq ◽  
Sequencing Platform ◽  
Yellow Dwarf Virus ◽  
Transcriptomic Level

Abstract Most plant viruses maintain complex interactions with their vector or nonvector insects and can indirectly (via host plants) or directly affect the fitness of insects. However, little is known about the genes involved in the interactions between insects and transmitted or nontransmitted viruses, particularly nontransmitted viruses. Sitobion avenae (Fabricius) is a vector of barley yellow dwarf virus GAV strains (BYDV-GAV), but not a vector of wheat dwarf virus (WDV), which is transmitted by the leafhopper [Psammotettix alienus (Dahlbom)]. In this study, S. avenae was utilized to determine the transcriptomic responses after feeding on wheat infected by each of the two viruses, respectively, using an Illumina Hiseq sequencing platform. The transcriptomic data presented 61,508 genes, of which 854 differentially expressed. Moreover, in addition to sharing 208 genes, the number of differentially expressed genes (DEGs) in S. avenae exposed to BYDV was higher (800) than that when exposed to WDV (262). The DEGs related to the immune system and fitness of S. avenae in response to BYDV-/WDV-infected plants were identified and analyzed using Gene Ontologies (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG), and the number of related DEGs was lower as nonvector than as vector. This study provides the baseline information to further examine molecular mechanisms of how wheat viruses affect S. avenae fitness and immune response either as a vector for BYDV-GAV or as a nonvector for WDV.

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