scholarly journals Circulative Nonpropagative Aphid Transmission of Nanoviruses: an Oversimplified View

2015 ◽  
Vol 89 (19) ◽  
pp. 9719-9726 ◽  
Author(s):  
Anne Sicard ◽  
Jean-Louis Zeddam ◽  
Michel Yvon ◽  
Yannis Michalakis ◽  
Serafin Gutiérrez ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Faba Bean ◽  
Plant Viruses ◽  
The Body ◽  
Virus Species ◽  
Content Type ◽  
Aphid Vector ◽  
Arthropod Vectors ◽  
The Family ◽  
Aphid Vectors

ABSTRACTPlant virus species of the familyNanoviridaehave segmented genomes with the highest known number of segments encapsidated individually. They thus likely represent the most extreme case of the so-called multipartite, or multicomponent, viruses. All species of the family are believed to be transmitted in a circulative nonpropagative manner by aphid vectors, meaning that the virus simply crosses cellular barriers within the aphid body, from the gut to the salivary glands, without replicating or even expressing any of its genes. However, this assumption is largely based on analogy with the transmission of other plant viruses, such as geminiviruses or luteoviruses, and the details of the molecular and cellular interactions between aphids and nanoviruses are poorly investigated. When comparing the relative frequencies of the eight genome segments in populations of the speciesFaba bean necrotic stunt virus(FBNSV) (genusNanovirus) within host plants and within aphid vectors fed on these plants, we unexpectedly found evidence of reproducible changes in the frequencies of some specific segments. We further show that these changes occur within the gut during early stages of the virus cycle in the aphid and not later, when the virus is translocated into the salivary glands. This peculiar observation, which was similarly confirmed in three aphid vector species,Acyrthosiphon pisum,Aphis craccivora, andMyzus persicae, calls for revisiting of the mechanisms of nanovirus transmission. It reveals an unexpected intimate interaction that may not fit the canonical circulative nonpropagative transmission.IMPORTANCEA specific mode of interaction between viruses and arthropod vectors has been extensively described in plant viruses in the three familiesLuteoviridae,Geminiviridae, andNanoviridae, but never in arboviruses of animals. This so-called circulative nonpropagative transmission contrasts with the classical biological transmission of animal arboviruses in that the corresponding viruses are thought to cross the vector cellular barriers, from the gut lumen to the hemolymph and to the salivary glands, without expressing any of their genes and without replicating. By monitoring the genetic composition of viral populations during the life cycle ofFaba bean necrotic stunt virus(FBNSV) (genusNanovirus), we demonstrate reproducible genetic changes during the transit of the virus within the body of the aphid vector. These changes do not fit the view that viruses simply traverse the bodies of their arthropod vectors and suggest more intimate interactions, calling into question the current understanding of circulative nonpropagative transmission.

scholarly journals Tropism, compartmentalization and retention of banana bunchy top virus (Nanoviridae) in the aphid vector Pentalonia nigronervosa

2013 ◽  
Vol 94 (1) ◽  
pp. 209-219 ◽  
Author(s):  
Shizu Watanabe ◽  
Alberto Bressan
Keyword(s):  
Salivary Glands ◽  
Time Course ◽  
Alimentary Tract ◽  
Plant Viruses ◽  
Banana Bunchy Top Virus ◽  
Aphid Vector ◽  
The Family ◽  
Aphid Vectors ◽  
Pentalonia Nigronervosa ◽  
Anterior Midgut

Plant viruses of the families Luteoviridae and Geminiviridae rely on hemipteran vectors for the infection of their hosts. Several lines of evidence have revealed that these viruses are transmitted by competent vectors in a circulative manner, involving entry into the vector’s body and the crossing of epithelial tissues forming the alimentary tract and the salivary glands. Similar to luteovirids and geminiviruses, a third family of plant viruses, the family Nanoviridae, have also been reported to be transmitted by aphids in a circulative manner. However, there is limited direct evidence of a possible path of translocation through the aphid vectors. Here, we used time-course experiments and transmission assays coupled with real-time PCR and immunofluorescence assays on dissected tissues to examine the translocation, compartmentalization and retention of banana bunchy top virus (BBTV) into the aphid vector Pentalonia nigronervosa. Our results indicate that BBTV translocates rapidly through the aphid vector; it is internalized into the anterior midgut in which it accumulates and is retained at concentrations higher than either the haemolymph or the principal salivary glands. Despite the large increase in viral concentration, we have failed to detect BBTV transcripts with RT-PCR. When tissues were not permeabilized, BBTV localized as distinct puncta in the proximity of the basal surface of the cells forming the anterior midgut and principal salivary glands, suggesting an on-going process of virion escape and internalization, respectively. Interestingly, we document that those organs can have direct contact within the aphid body, suggesting a possible haemolymph-independent translocation path.

scholarly journals Route of a Multipartite Nanovirus across the Body of Its Aphid Vector

2020 ◽  
Vol 94 (9) ◽  
Author(s):  
Jérémy Di Mattia ◽  
Marie-Stéphanie Vernerey ◽  
Michel Yvon ◽  
Elodie Pirolles ◽  
Mathilde Villegas ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Plant Viruses ◽  
The Body ◽  
Insect Vector ◽  
Vector Transmission ◽  
Aphid Vector ◽  
Vector Interaction ◽  
Salivary Gland Cells ◽  
Mode Of Transmission

ABSTRACT Vector transmission plays a primary role in the life cycle of viruses, and insects are the most common vectors. An important mode of vector transmission, reported only for plant viruses, is circulative nonpropagative transmission whereby the virus cycles within the body of its insect vector, from gut to salivary glands and saliva, without replicating. This mode of transmission has been extensively studied in the viral families Luteoviridae and Geminiviridae and is also reported for Nanoviridae. The biology of viruses within these three families is different, and whether the viruses have evolved similar molecular/cellular virus-vector interactions is unclear. In particular, nanoviruses have a multipartite genome organization, and how the distinct genome segments encapsidated individually transit through the insect body is unknown. Here, using a combination of fluorescent in situ hybridization and immunofluorescence, we monitor distinct proteins and genome segments of the nanovirus Faba bean necrotic stunt virus (FBNSV) during transcytosis through the gut and salivary gland cells of its aphid vector Acyrthosiphon pisum. FBNSV specifically transits through cells of the anterior midgut and principal salivary gland cells, a route similar to that of geminiviruses but distinct from that of luteoviruses. Our results further demonstrate that a large number of virus particles enter every single susceptible cell so that distinct genome segments always remain together. Finally, we confirm that the success of nanovirus-vector interaction depends on a nonstructural helper component, the viral protein nuclear shuttle protein (NSP), which is shown to be mandatory for viral accumulation within gut cells. IMPORTANCE An intriguing mode of vector transmission described only for plant viruses is circulative nonpropagative transmission, whereby the virus passes through the gut and salivary glands of the insect vector without replicating. Three plant virus families are transmitted this way, but details of the molecular/cellular mechanisms of the virus-vector interaction are missing. This is striking for nanoviruses that are believed to interact with aphid vectors in ways similar to those of luteoviruses or geminiviruses but for which empirical evidence is scarce. We here confirm that nanoviruses follow a within-vector route similar to that of geminiviruses but distinct from that of luteoviruses. We show that they produce a nonstructural protein mandatory for viral entry into gut cells, a unique phenomenon for this mode of transmission. Finally, noting that nanoviruses are multipartite viruses, we demonstrate that a large number of viral particles penetrate susceptible cells of the vector, allowing distinct genome segments to remain together.

The nexus of aging in family businesses

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cagri Bulut ◽  
Serpil Kahraman ◽  
Emir Ozeren ◽  
Sobia Nasir
Keyword(s):  
Decision Making ◽  
Life Expectancy ◽  
Intergenerational Relationships ◽  
Family Businesses ◽  
The Body ◽  
Sustainable Growth ◽  
Future Research ◽  
Content Type ◽  
The Family ◽  
The Future

Purpose The purpose of this paper is to elaborate on the preferences of parent founders within family businesses in selecting a suitable successor with the increase in life expectancy. Design/methodology/approach The study presents alternative decision-making preference models of a suitable succession for parent founders based on the models of microeconomic theory in the context of family businesses. Findings The theories and models of economics in the current study illustrate that the increase in the life expectancy of the parent founders with their decisions toward the preference of a suitable successor under the age constraint may restrict the sustainability of their family businesses. As a result, the opportunity cost theory appears as to be at the ahead of the other theories in microeconomics in order to support the decision making of parent founders on selecting the suitable successor for the future of the family business. Research limitations/implications The paper illustrates the models on the preferences of the parent founder for the future of the family businesses with their perception toward the increase in overall life expectancy. The current study is limited to the perspectives of founder entrepreneurs toward an effective succession decision. Future research may consider the perspectives of in-family as well as non-family successors. Originality/value In the light of alternative preference decision-making models for parent founders for choosing a suitable successor under the age constraint, this study will make a noteworthy contribution to the sustainable growth of their family businesses. The approach of this study through the microeconomics not only methodologically contributes to the body of knowledge in aging and employment in general, but also to the intergenerational relationships of parent founders, especially their succession-related plans at their early stages of career.

scholarly journals Prevalence and Diversity of Viruses in the Entomopathogenic Fungus Beauveria bassiana

2012 ◽  
Vol 78 (24) ◽  
pp. 8523-8530 ◽  
Author(s):  
Noemí Herrero ◽  
Encarna Dueñas ◽  
Enrique Quesada-Moraga ◽  
Iñigo Zabalgogeazcoa
Keyword(s):  
Beauveria Bassiana ◽  
Entomopathogenic Fungi ◽  
Viral Infections ◽  
Biological Control Agent ◽  
Rna Virus ◽  
Plant Viruses ◽  
Hybridization Experiment ◽  
Virus Species ◽  
Content Type ◽  
Virus Diversity

ABSTRACTViruses have been discovered in numerous fungal species, but unlike most known animal or plant viruses, they are rarely associated with deleterious effects on their hosts. The knowledge about viruses among entomopathogenic fungi is very limited, although their existence is suspected because of the presence of virus-like double-stranded RNA (dsRNA) in isolates of several species.Beauveria bassianais one of the most-studied species of entomopathogenic fungi; it has a cosmopolitan distribution and is used as a biological control agent against invertebrates in agriculture. We analyzed a collection of 73 isolates obtained at different locations and from different habitats in Spain and Portugal, searching for dsRNA elements indicative of viral infections. The results revealed that the prevalence of viral infections is high; 54.8% of the isolates contained dsRNA elements with viral characteristics. The dsRNA electropherotypes of infected isolates indicated that virus diversity was high in the collection analyzed and that mixed virus infections occurred in fungal isolates. However, a hybridization experiment indicated that dsRNA bands that are similar in size do not always have similar sequences. Particular virus species or dsRNA profiles were not associated with locations or types of habitats, probably because of the ubiquity and efficient dispersion of this fungus as an airborne species. The sequence of one of the most common dsRNA elements corresponded to the 5.2-kbp genome of a previously undescribed member of theTotiviridaefamily, termedB. bassianaRNA virus 1 (BbRV1).

scholarly journals Full genome characterization of Laem Singh virus (LSNV) in shrimp Penaeus monodon

2020 ◽  
Author(s):  
Suparat Taengchaiyaphum ◽  
Jiraporn Srisala ◽  
Piyachat Sanguanrut ◽  
Chalermporn Ongvarrasopone ◽  
Timothy W. Flegel ◽  
...  
Keyword(s):  
Penaeus Monodon ◽  
Plant Viruses ◽  
Virus Species ◽  
Full Genome ◽  
Cloning And Sequencing ◽  
Genome Characterization ◽  
Sequence Identity ◽  
The Family ◽  
Shrimp Virus

ABSTRACTLaem Singh virus (LSNV) was discovered in 2006 and proposed as a necessary but insufficient cause of retarded growth in the giant tiger shrimp Penaeus monodon. Its closest relatives were plant viruses including an unassigned Sobemovirus and viruses in the family Luteoviridae. During succeeding years, attempts to obtain the full LSNV genome sequence by genome walking failed. However, recent publication of the full sequence of Wenzhou shrimp virus 9 (WZSV 9) at GenBank revealed that LSNV sequences in our database shared 99% sequence identity with it. Thus, we hypothesized that LSNV and WZSV 9 were different isolates of the same virus species. Here we confirm that hypothesis by cloning and sequencing of the full genome of LSNV from P. monodon and by showing that it consists of two fragments each with 99% identity to the matching fragments of WZSV.

scholarly journals Natural Infection of Vicia faba by Bidens mottle virus in Florida

Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1290-1290 ◽  
Author(s):  
C. A. Baker ◽  
R. N. Raid ◽  
B. T. Scully
Keyword(s):  
Vicia Faba ◽  
Faba Bean ◽  
Natural Infection ◽  
Light And Electron Microscopy ◽  
Plant Viruses ◽  
Mottle Virus ◽  
Primary Host ◽  
Geographic Origins ◽  
Initial Symptoms ◽  
Aphid Vectors

In a study to evaluate the potential of Vicia faba (faba bean) as a cover and forage crop for Florida, 60 accessions of faba bean with diverse genetic backgrounds and geographic origins were acquired from the USDA Germplasm Repository in Pullman, WA. The beans were grown south of Lake Okeechobee in Belle Glade, FL, from December 2000 to April 2001. Reddish-brown elliptical lesions first appeared on the leaflets of two of the faba bean plants 10 to 12 weeks after planting. Within 2 weeks of initial symptoms, a mosaic pattern was expressed on the newly emergent leaves of the same plants. After disease expression, new pods aborted, while developing pods became stunted, distorted, and blistered. Potyvirus cylindrical inclusions (CI) were found in leaf strips (1) of the original plants. Viral symptoms were expressed in manually inoculated plants of Chenopodium amaraticolor, C. quinoa, Lactuca sativa, Nicotiana benthamiana, Petunia × hybrida, Verbena × hybrida, Vicia faba, and Zinnia elegans. Inoculated species of Phaseolus and Pisum were not infected. The virus causing the disease was identified as Bidens mottle virus (2) based on host range, characteristic CI in Z. elegans, and homologous lines of precipitation in SDS-immunodiffusion using antiserum to Bidens mottle and a known antigen. Both the primary host of this virus Bidens mottle virus and its aphid vectors are ubiquitous throughout Florida. To our knowledge, this is the first report of Bidens mottle virus infecting a member of the Leguminosae. References: (1) R. G. Christie and J. R. Edwardson. Light and Electron Microscopy of Plant Virus. Monogr. 9, IFAS, University of Florida, 1994. (2) D. E. Purcifull et al. Bidens mottle virus. Descriptions of Plant Viruses. No. 161. CMI/AAB, Surrey, England, 1976.

scholarly journals Co-Acquired Nanovirus and Geminivirus Exhibit a Contrasted Localization within Their Common Aphid Vector

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 299 ◽  
Author(s):  
Jérémy Di Mattia ◽  
Faustine Ryckebusch ◽  
Marie-Stéphanie Vernerey ◽  
Elodie Pirolles ◽  
Nicolas Sauvion ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Host Plants ◽  
Virus Transmission ◽  
Plant Viruses ◽  
The Body ◽  
Nuclear Shuttle Protein ◽  
Aphid Vector ◽  
Taxonomic Criterion ◽  
Alfalfa Leaf ◽  
Leaf Curl Virus

Single-stranded DNA (ssDNA) plant viruses belong to the families Geminiviridae and Nanoviridae. They are transmitted by Hemipteran insects in a circulative, mostly non-propagative, manner. While geminiviruses are transmitted by leafhoppers, treehoppers, whiteflies and aphids, nanoviruses are transmitted exclusively by aphids. Circulative transmission involves complex virus–vector interactions in which epithelial cells have to be crossed and defense mechanisms counteracted. Vector taxa are considered a relevant taxonomic criterion for virus classification, indicating that viruses can evolve specific interactions with their vectors. Thus, we predicted that, although nanoviruses and geminiviruses represent related viral families, they have evolved distinct interactions with their vector. This prediction is also supported by the non-structural Nuclear Shuttle Protein (NSP) that is involved in vector transmission in nanoviruses but has no similar function in geminiviruses. Thanks to the recent discovery of aphid-transmitted geminiviruses, this prediction could be tested for the geminivirus alfalfa leaf curl virus (ALCV) and the nanovirus faba bean necrotic stunt virus (FBNSV) in their common vector, Aphis craccivora. Estimations of viral load in midgut and head of aphids, precise localization of viral DNA in cells of insect vectors and host plants, and virus transmission tests revealed that the pathway of the two viruses across the body of their common vector differs both quantitatively and qualitatively.

Effects of an alphasatellite on life cycle of the nanovirus Faba bean necrotic yellows virus

2021 ◽  
Author(s):  
Mahsa Mansourpour ◽  
Romain Gallet ◽  
Alireza Abbasi ◽  
Stephane Blanc ◽  
Akbar Dizadji ◽  
...  
Keyword(s):  
Host Plant ◽  
Faba Bean ◽  
Acyrthosiphon Pisum ◽  
Subterranean Clover ◽  
Plant Viruses ◽  
Single Stranded Dna ◽  
Virus Load ◽  
Aphid Vector ◽  
The Impact ◽  
Viral Accumulation

Nanoviruses are plant viruses with a multipartite single-stranded DNA (ssDNA) genome. Alphasatellites are commonly associated with nanovirus infections, but their putative impact on their helper viruses is unknown. In this study, we investigated the role of subterranean clover stunt alphasatellite 1 (hereafter named SCSA 1) on various important traits of faba bean necrotic yellows virus (FBNYV) in its host plant Vicia faba and aphid vector Acyrthosiphon pisum , including disease symptoms, viral accumulation and transmission. The results indicate that SCSA 1 does not affect the symptom severity nor the overall FBNYV accumulation in V. faba, but changes the relative amounts of its different genomic segments. Moreover, the association of SCSA 1 with FBNYV increases the rate of plant-to-plant transmission by a process seemingly unrelated to simple increase of the viral accumulation in the vector. These results represent the first study on the impact of an alphasatellite on the biology of its helper nanovirus. They suggest that SCSA 1 may benefit FBNYV, but the genericity of this conclusion is discussed and questioned. Importance Alphasatellites are circular single stranded DNA molecules frequently found in association with natural isolates of nanoviruses and some geminiviruse, the two ssDNA plant infecting virus families. While the implications of alphasatellite presence in geminivirus infections are relatively well documented, comparable studies on alphasatellites associated with nanoviruses are not available. Here we confirm that subterranean clover stunt alphasatellite 1 affects different traits of its helper nanovirus, faba bean necrotic yellows virus, both in the host plant and aphid vector. We show that the frequencies of the virus segments change in the presence of alphasatellite, in both plant and vector. We also confirm that while within-plant virus load and symptom are not affected by alphasatellite, the presence of alphasatellite decreases within-aphid virus load, but significantly increases virus transmission rate, so may confer a possible evolutionary advantage for the helper virus.

Three new species, two new genera, and new family Biphragmosagittidae (Сhaetognatha) from Southwest Pacific Ocean

2011 ◽  
Vol 20 (1) ◽  
pp. 161-173
Author(s):  
A.P. Kassatkina
Keyword(s):  
New Species ◽  
Type Species ◽  
Morphological Characters ◽  
The Body ◽  
New Order ◽  
New Genera ◽  
New Family ◽  
The Family ◽  
Three New Species

Resuming published and own data, a revision of classification of Chaetognatha is presented. The family Sagittidae Claus & Grobben, 1905 is given a rank of subclass, Sagittiones, characterised, in particular, by the presence of two pairs of sac-like gelatinous structures or two pairs of fins. Besides the order Aphragmophora Tokioka, 1965, it contains the new order Biphragmosagittiformes ord. nov., which is a unique group of Chaetognatha with an unusual combination of morphological characters: the transverse muscles present in both the trunk and the tail sections of the body; the seminal vesicles simple, without internal complex compartments; the presence of two pairs of lateral fins. The only family assigned to the new order, Biphragmosagittidae fam. nov., contains two genera. Diagnoses of the two new genera, Biphragmosagitta gen. nov. (type species B. tarasovi sp. nov. and B. angusticephala sp. nov.) and Biphragmofastigata gen. nov. (type species B. fastigata sp. nov.), detailed descriptions and pictures of the three new species are presented.

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