scholarly journals Unresolved advantages of multipartitism in spatially structured environments

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mark P Zwart ◽  
Stéphane Blanc ◽  
Marcelle Johnson ◽  
Susanna Manrubia ◽  
Yannis Michalakis ◽  
...  
Keyword(s):  
Genome Organization ◽  
Latent Infection ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Epidemic Spread ◽  
Virus Particles ◽  
Distinct Virus ◽  
Network Epidemiology ◽  
Short Commentary ◽  
Animal Hosts

Abstract Multipartite viruses have segmented genomes and package each of their genome segments individually into distinct virus particles. Multipartitism is common among plant viruses, but why this apparently costly genome organization and packaging has evolved remains unclear. Recently Zhang and colleagues developed network epidemiology models to study the epidemic spread of multipartite viruses and their distribution over plant and animal hosts (Phys. Rev. Lett. 2019, 123, 138101). In this short commentary, we call into question the relevance of these results because of key model assumptions. First, the model of plant hosts assumes virus transmission only occurs between adjacent plants. This assumption overlooks the basic but imperative fact that most multipartite viruses are transmitted over variable distances by mobile animal vectors, rendering the model results irrelevant to differences between plant and animal hosts. Second, when not all genome segments of a multipartite virus are transmitted to a host, the model assumes an incessant latent infection occurs. This is a bold assumption for which there is no evidence to date, making the relevance of these results to understanding multipartitism questionable.

scholarly journals Aphid endosymbiont facilitates virus transmission by modulating the volatile profile of host plants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiao-Bin Shi ◽  
Shuo Yan ◽  
Chi Zhang ◽  
Li-Min Zheng ◽  
Zhan-Hong Zhang ◽  
...  
Keyword(s):  
Host Plants ◽  
Green Peach Aphid ◽  
Virus Transmission ◽  
Feeding Preference ◽  
Plant Viruses ◽  
Volatile Profile ◽  
Cmv Infection ◽  
Buchnera Aphidicola ◽  
Plant Volatile ◽  
Volatile Profiles

Abstract Background Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory. Results Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants. Conclusions We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector’s feeding preference from infected to healthy plants.

scholarly journals Interactions between a luteovirus and the GroEL chaperonin protein of the symbiotic bacterium Buchnera aphidicola of aphids

2011 ◽  
Vol 92 (6) ◽  
pp. 1467-1474 ◽  
Author(s):  
Sophie Bouvaine ◽  
Neil Boonham ◽  
Angela E. Douglas
Keyword(s):  
Binding Site ◽  
Barley Yellow Dwarf Virus ◽  
Fat Body ◽  
Symbiotic Bacterium ◽  
Plant Viruses ◽  
Virus Binding ◽  
Buchnera Aphidicola ◽  
Virus Particles ◽  
Groel Protein ◽  
Virus Interactions

Luteoviruses and poleroviruses are important plant viruses transmitted exclusively by aphids in a circulative manner via the aphid haemolymph. A chaperonin protein, GroEL, synthesized in aphids by a symbiotic bacterium, Buchnera aphidicola, is hypothesized to bind to virus particles in the haemolymph, thereby promoting transmission. To investigate this hypothesis, the GroEL-binding site for barley yellow dwarf virus (BYDV) was determined in vitro, and the abundance of GroEL protein in different aphid tissues was investigated. Virus binding to a peptide library representing the full GroEL molecule revealed a single binding site that coincides with the site that anchors two GroEL rings to form the native GroEL tetradecamer. In the functional form of the GroEL protein, virus binding would compete with the formation of the two GroEL rings. Using a mAb raised against a Buchnera-specific GroEL epitope, GroEL was detected in Buchnera cells by immunoblotting and immunocytochemistry, but not in the aphid haemolymph, fat body or gut. From the prediction here that GroEL–virus interactions are probably severely limited by competition with other GroEL molecules, and the evidence that GroEL is not available to interact with virus particles in vivo, it is concluded that GroEL–virus interactions are unlikely to contribute to virus transmission by aphids.

scholarly journals Investigations of the mechanism of the transmission of plant viruses by insect vectors III. The insect’s saliva

1939 ◽  
Vol 127 (849) ◽  
pp. 526-543 ◽  
Keyword(s):  
Direct Evidence ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Convincing Evidence ◽  
Transmission Characteristic ◽  
Insect Vectors ◽  
Leaf Hopper

For the type of virus transmission characteristic of leaf hopper vectors, there is convincing evidence that the virus passes through the insect's body. The manner in which it emerges from the insect and comes to be inoculated into a plant is much less certainly known. It has generally been assumed that the saliva is the vehicle of the inoculation. For this assumption there is even now little direct evidence. I now describe observations on the excretion of saliva by a leafhopper and attempts to demonstrate experimentally in this saliva the virus of which this insect is a specific vector.

scholarly journals Citrus tristeza virus P33 Protein Is Required for Efficient Transmission by the Aphid Aphis (Toxoptera) citricidus (Kirkaldy)

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1131
Author(s):  
Turksen Shilts ◽  
Choaa El-Mohtar ◽  
William O. Dawson ◽  
Nabil Killiny
Keyword(s):  
Citrus Tristeza Virus ◽  
Transmission Rate ◽  
Control Strategies ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Transmission Mechanisms ◽  
Infectious Clones ◽  
Underlying Mechanisms ◽  
Tristeza Virus ◽  
Citrus Tristeza

Plant viruses are threatening many valuable crops, and Citrus tristeza virus (CTV) is considered one of the most economically important plant viruses. CTV has destroyed millions of citrus trees in many regions of the world. Consequently, understanding of the transmission mechanism of CTV by its main vector, the brown citrus aphid, Aphis (Toxoptera) citricidus (Kirkaldy), may lead to better control strategies for CTV. The objective of this study was to understand the CTV–vector relationship by exploring the influence of viral genetic diversity on virus transmission. We built several infectious clones with different 5′-proximal ends from different CTV strains and assessed their transmission by the brown citrus aphid. Replacement of the 5′- end of the T36 isolate with that of the T30 strain (poorly transmitted) did not increase the transmission rate of T36, whereas replacement with that of the T68-1 isolate (highly transmitted) increased the transmission rate of T36 from 1.5 to 23%. Finally, substitution of p33 gene of the T36 strain with that of T68 increased the transmission rate from 1.5% to 17.8%. Although the underlying mechanisms that regulate the CTV transmission process by aphids have been explored in many ways, the roles of specific viral proteins are still not explicit. Our findings will improve our understanding of the transmission mechanisms of CTV by its aphid vector and may lead to the development of control strategies that interfere with its transmission by vector.

scholarly journals Actin Cytoskeleton Is Involved in Targeting of a Viral Hsp70 Homolog to the Cell Periphery

2005 ◽  
Vol 79 (22) ◽  
pp. 14421-14428 ◽  
Author(s):  
Alexey I. Prokhnevsky ◽  
Valera V. Peremyslov ◽  
Valerian V. Dolja
Keyword(s):  
Actin Cytoskeleton ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Fluorescent Proteins ◽  
Cell Movement ◽  
Plant Viruses ◽  
Cell Periphery ◽  
Virus Particles ◽  
Shock Proteins

ABSTRACT The cell-to-cell movement of plant viruses involves translocation of virus particles or nucleoproteins to and through the plasmodesmata (PDs). As we have shown previously, the movement of the Beet yellows virus requires the concerted action of five viral proteins including a homolog of cellular ∼70-kDa heat shock proteins (Hsp70h). Hsp70h is an integral component of the virus particles and is also found in PDs of the infected cells. Here we investigate subcellular distribution of Hsp70h using transient expression of Hsp70h fused to three spectrally distinct fluorescent proteins. We found that fluorophore-tagged Hsp70h forms motile granules that are associated with actin microfilaments, but not with microtubules. In addition, immobile granules were observed at the cell periphery. A pairwise appearance of these granules at the opposite sides of cell walls and their colocalization with the movement protein of Tobacco mosaic virus indicated an association of Hsp70h with PDs. Treatment with various cytoskeleton-specific drugs revealed that the intact actomyosin motility system is required for trafficking of Hsp70h in cytosol and its targeting to PDs. In contrast, none of the drugs interfered with the PD localization of Tobacco mosaic virus movement protein. Collectively, these findings suggest that Hsp70h is translocated and anchored to PDs in association with the actin cytoskeleton.

ELECTRON MICROSCOPY OF TWO SMALL SPHERICAL PLANT VIRUSES IN THIN SECTIONS

1966 ◽  
Vol 44 (6) ◽  
pp. 821-826 ◽  
Author(s):  
J. R. Edwardson ◽  
D. E. Purcifull ◽  
R. G. Christie
Keyword(s):  
Electron Microscopy ◽  
Mosaic Virus ◽  
Leaf Tissue ◽  
Plant Viruses ◽  
Tobacco Necrosis Virus ◽  
Necrosis Virus ◽  
Thin Sections ◽  
Virus Particles ◽  
Southern Bean Mosaic Virus

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.

scholarly journals Tenuivirususes a molecular bridge strategy to overcome insect midgut barriers for virus persistent transmission

2018 ◽  
Author(s):  
Gang Lu ◽  
Shuo Li ◽  
Changwei Zhou ◽  
Xin Qian ◽  
Qing Xiang ◽  
...  
Keyword(s):  
Brown Planthopper ◽  
Specific Interaction ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Insect Vector ◽  
Terminal Protein ◽  
Insect Midgut ◽  
Helper Component ◽  
Vector Interaction ◽  
Molecular Bridge

AbstractMany persistent transmitted plant viruses, includingRice stripe tenuivirus(RSV), cause serious damages to crop productions in China and worldwide. Although many reports have indicated that successful insect-mediated virus transmission depends on proper virus–insect vector interactions, the mechanism(s) controlling interactions between viruses and insect vectors for virus persistent transmission remained poorly understood. In this study, we used RSV and its small brown planthopper (SBPH) vector as a working model to elucidate the molecular mechanism controlling RSV virion entrance into SBPH midgut for persistent transmission. We have now demonstrated that this non-envelopedTenuivirususes its non-structural glycoprotein NSvc2 as a helper component to bridge the specific interaction between virion and SBPH midgut cells, leading to overcome SBPH midgut barriers for virus persistent transmission. In the absence of this glycoprotein, purified RSV virion is not capable of entering SBPH midgut cells. In RSV-infected cells, glycoprotein NSvc2 is processed into two mature proteins: an amino-terminal protein NSvc2-N and a carboxyl-terminal protein NSvc2-C. We determined that NSvc2-N interacted with RSV virion and bound directly to midgut lumen surface via its N-glycosylation sites. Upon recognition by midgut cells, the midgut cells underwent endocytosis followed by compartmentalizing RSV virion and NSvc2 into early and then late endosomes. The acidic condition inside the late endosome triggered conformation change of NSvc2-C and caused cell membrane fusion via its highly conserved fusion loop motifs, leading to the release of RSV virion from endosome into cytosol. In summary, our results showed for the first time that a riceTenuivirususes a molecular bridge strategy to ensure proper interactions between virus and insect midgut for successful persistent transmission.Author summaryOver 75% of the known plant viruses are insect transmitted. Understanding how plant viruses interacted with their insect vectors during virus transmission is one of the key steps to manage virus diseases worldwide. Both the direct and indirect virus–insect vector interaction models have been proposed for virus non-persistent and semi-persistent transmission. However, the indirect virus–vector interaction mechanism during virus persistent transmission has not been reported previously. In this study, we developed a new reverse genetics technology and demonstrated that the circulative and propagative transmittedRice stripe tenuivirusutilizes a glycoprotein NSvc2 as a helper component to ensure a specific interaction betweenTenuivirusvirion and midgut cells of small brown planthopper (SBPH), leading to conquering the midgut barrier of SBPH. This is the first report of a helper component mediated-molecular bridge mechanism for virus persistent transmission. These new findings and our new model on persistent transmission expand our understanding of molecular mechanism(s) controlling virus–insect vector interactions during virus transmission in nature.

scholarly journals Karakterisasi Virus Penyebab Penyakit Belang pada Tanaman Lada (Piper nigrum L.)

2018 ◽  
Vol 22 (1) ◽  
pp. 115
Author(s):  
Trisnani Alif ◽  
Sedyo Hartono ◽  
Sri Sulandari
Keyword(s):  
Polymerase Chain Reaction ◽  
Virus Transmission ◽  
Mottle Virus ◽  
Piper Nigrum ◽  
Chain Reaction ◽  
Virus Particles ◽  
Yellow Mottle ◽  
Polymerase Chain ◽  
Transmission Studies ◽  
Pepper Plants

Mottle disease is an important disease in pepper plants caused by Piper yellow mottle virus (PYMoV). This study aims to determine the characterization of PYMoV biologically and molecularly. The pepper plant samples were obtained from pepper farmland in Kleben, Putat (Yogyakarta), and Air Buluh (Bangka). Virus particles are measured by electron microscopy. Virus transmission studies include mechanical transmission, vector, cuttings, grafting, and seeds. The molecular detection was done by using Polymerase chain reaction (PCR) method with PYMoV-F and PYMoV-R specific primers. The result, virus particles were found to be ± 30×130 nm in shape. Virus transmission studies indicate that PYMoV can be transmitted by Ferrisia virgata vectors, cuttings, grafts and seeds but cannot be transmitted through mechanical inoculation. Molecular test results showed that samples of Kleben, Putat and Air Buluh pepper plants were positively detected to contain PYMoV and amplified at 400 bp. The result of nucleotide base sequence analysis showed the isolates of Putat and Air Buluh had the highest homology with PYMoV of India 2 about 95% while Kleben isolate had 96% homology with PYMoV of India 1. IntisariPenyakit belang merupakan salah satu penyakit penting pada tanaman lada yang disebabkan oleh Piper yellow mottle virus (PYMoV). Penelitian ini bertujuan untuk mengetahui karakterisasi PYMoV secara biologi dan molekuler. Sampel tanaman lada diperoleh dari lahan petani lada di Desa Kleben, Putat (Yogyakarta), dan Air Buluh (Bangka). Partikel virus diukur dengan mikroskop elektron. Kajian penularan virus meliputi penularan mekanik, vektor, stek, penyambungan, dan biji. Deteksi secara molekuler dengan metode Polymerase chain reaction (PCR) dengan pasangan primer spesifik PYMoV-F dan PYMoV-R. Partikel virus yang ditemukan berukuran ± 30×130 nm berbentuk batang. Kajian penularan virus menunjukkan bahwa PYMoV dapat ditularkan melalui vektor Ferrisia virgata, stek, penyambungan dan biji namun tidak dapat ditularkan melalui inokulasi mekanik. Hasil uji molekuler menunjukkan bahwa sampel tanaman lada Kleben, Putat dan Air Buluh positif terdeteksi PYMoV dan teramplifikasi pada 400 bp. Hasil analisis sekuen basa nukleotida menunjukkan isolat Putat dan Air Buluh memiliki homologi tertinggi dengan PYMoV India 2 sekitar 95% sedangkan isolat Kleben memiliki homologi 96% dengan PYMoV India 1.

scholarly journals Epidemiological and ecological consequences of virus manipulation of host and vector in plant virus transmission

2021 ◽  
Author(s):  
Nik J. Cunniffe ◽  
Nick P. Taylor ◽  
Frédéric M. Hamelin ◽  
Michael J. Jeger
Keyword(s):  
Population Dynamics ◽  
Plant Virus ◽  
Complex Dynamics ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Infection Status ◽  
Vector Behaviour ◽  
Interactive Interface ◽  
Vector Population ◽  
Plant Infection

ABSTRACTMany plant viruses are transmitted by insect vectors. Transmission can be described as persistent or non-persistent depending on rates of acquisition, retention, and inoculation of virus. Much experimental evidence has accumulated indicating vectors can prefer to settle and/or feed on infected versus noninfected host plants. For persistent transmission, vector preference can also be conditional, depending on the vector’s own infection status. Since viruses can alter host plant quality as a resource for feeding, infection potentially also affects vector population dynamics. Here we use mathematical modelling to develop a theoretical framework addressing the effects of vector preferences for landing, settling and feeding – as well as potential effects of infection on vector population density – on plant virus epidemics. We explore the consequences of preferences that depend on the host (infected or healthy) and vector (viruliferous or nonviruliferous) phenotypes, and how this is affected by the form of transmission, persistent or non-persistent. We show how different components of vector preference have characteristic effects on both the basic reproduction number and the final incidence of disease. We also show how vector preference can induce bistability, in which the virus is able to persist even when it cannot invade from very low densities. Feedbacks between plant infection status, vector population dynamics and virus transmission potentially lead to very complex dynamics, including sustained oscillations. Our work is supported by an interactive interface https://plantdiseasevectorpreference.herokuapp.com/. Our model reiterates the importance of coupling virus infection to vector behaviour, life history and population dynamics to fully understand plant virus epidemics.

scholarly journals Chimeric Plant Virus Particles Administered Nasally or Orally Induce Systemic and Mucosal Immune Responses in Mice

1999 ◽  
Vol 73 (2) ◽  
pp. 930-938 ◽  
Author(s):  
Frank R. Brennan ◽  
Trevor Bellaby ◽  
Sharon M. Helliwell ◽  
Tim D. Jones ◽  
Søren Kamstrup ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plant Virus ◽  
Oral Immunization ◽  
Plant Viruses ◽  
T Helper 1 ◽  
Virus Particles ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Recombinant Plant ◽  
Chimeric Plant

ABSTRACT The humoral immune responses to the D2 peptide of fibronectin-binding protein B (FnBP) of Staphylococcus aureus, expressed on the plant virus cowpea mosaic virus (CPMV), were evaluated after mucosal delivery to mice. Intranasal immunization of these chimeric virus particles (CVPs), either alone or in the presence of ISCOM matrix, primed CPMV-specific T cells and generated high titers of CPMV- and FnBP-specific immunoglobulin G (IgG) in sera. Furthermore, CPMV- and FnBP-specific IgA and IgG could also be detected in the bronchial, intestinal, and vaginal lavage fluids, highlighting the ability of CVPs to generate antibody at distant mucosal sites. IgG2a and IgG2b were the dominant IgG subclasses in sera to both CPMV and FnBP, demonstrating a bias in the response toward the T helper 1 type. The sera completely inhibited the binding of human fibronectin to the S. aureus FnBP. Oral immunization of the CVPs also generated CPMV- and FnBP-specific serum IgG; however, these titers were significantly lower and more variable than those generated by the intranasal route, and FnBP-specific intestinal IgA was undetectable. Neither the ISCOM matrix nor cholera toxin enhanced these responses. These studies demonstrate for the first time that recombinant plant viruses have potential as mucosal vaccines without the requirement for adjuvant and that the nasal route is most effective for the delivery of these nonreplicating particles.

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