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1.
Viruses ; 13(1)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478068

RESUMO

The green peach aphid Myzus persicae Sulzer is the main vector of the semipersistently transmitted and phloem-limited Beet yellows virus (BYV, Closterovirus). Studies monitoring the M. persicae probing behavior by using the Electrical penetration graphs (EPG) technique revealed that inoculation of BYV occurs during unique brief intracellular punctures (phloem-pds) produced in companion and/or sieve element cells. Intracellular stylet punctures (or pds) are subdivided in three subphases (II-1, II-2 and II-3), which have been related to the delivery or uptake of non-phloem limited viruses transmitted in a non-persistent or semipersistent manner. As opposed to non-phloem limited viruses, the specific pd subphase(s) involved in the successful delivery of phloem limited viruses by aphids remain unknown. Therefore, we monitored the feeding process of BYV-carrying M. persicae individuals in sugar beet plants by the EPG technique and the feeding process was artificially terminated at each phloem-pd subphase. Results revealed that aphids that only performed the subphase II-1 of the phloem-pd transmitted BYV at similar efficiency than those allowed to perform subphase II-2 or the complete phloem-pd. This result suggests that BYV inoculation occurs during the first subphase of the phloem-pd. The specific transmission mechanisms involved in BYV delivery in phloem cells are discussed.


Assuntos
Floema/virologia , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Animais , Afídeos/virologia , Interações Hospedeiro-Patógeno , Internalização do Vírus
2.
Viruses ; 13(1)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478128

RESUMO

Plant viruses cause devastating diseases in many agriculture systems, being a serious threat for the provision of adequate nourishment to a continuous growing population. At the present, there are no chemical products that directly target the viruses, and their control rely mainly on preventive sanitary measures to reduce viral infections that, although important, have proved to be far from enough. The current most effective and sustainable solution is the use of virus-resistant varieties, but which require too much work and time to obtain. In the recent years, the versatile gene editing technology known as CRISPR/Cas has simplified the engineering of crops and has successfully been used for the development of viral resistant plants. CRISPR stands for 'clustered regularly interspaced short palindromic repeats' and CRISPR-associated (Cas) proteins, and is based on a natural adaptive immune system that most archaeal and some bacterial species present to defend themselves against invading bacteriophages. Plant viral resistance using CRISPR/Cas technology can been achieved either through manipulation of plant genome (plant-mediated resistance), by mutating host factors required for viral infection; or through manipulation of virus genome (virus-mediated resistance), for which CRISPR/Cas systems must specifically target and cleave viral DNA or RNA. Viruses present an efficient machinery and comprehensive genome structure and, in a different, beneficial perspective, they have been used as biotechnological tools in several areas such as medicine, materials industry, and agriculture with several purposes. Due to all this potential, it is not surprising that viruses have also been used as vectors for CRISPR technology; namely, to deliver CRISPR components into plants, a crucial step for the success of CRISPR technology. Here we discuss the basic principles of CRISPR/Cas technology, with a special focus on the advances of CRISPR/Cas to engineer plant resistance against DNA and RNA viruses. We also describe several strategies for the delivery of these systems into plant cells, focusing on the advantages and disadvantages of the use of plant viruses as vectors. We conclude by discussing some of the constrains faced by the application of CRISPR/Cas technology in agriculture and future prospects.


Assuntos
Engenharia Genética , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Agricultura/métodos , Sistemas CRISPR-Cas , Produtos Agrícolas/virologia , Resistência à Doença/genética , Edição de Genes , Expressão Gênica , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Genoma Viral , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/genética
3.
Nat Commun ; 11(1): 5610, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33154373

RESUMO

Infection by multiple pathogens of the same host is ubiquitous in both natural and managed habitats. While intraspecific variation in disease resistance is known to affect pathogen occurrence, how differences among host genotypes affect the assembly of pathogen communities remains untested. In our experiment using cloned replicates of naive Plantago lanceolata plants as sentinels during a seasonal virus epidemic, we find non-random co-occurrence patterns of five focal viruses. Using joint species distribution modelling, we attribute the non-random virus occurrence patterns primarily to differences among host genotypes and local population context. Our results show that intraspecific variation among host genotypes may play a large, previously unquantified role in pathogen community structure.


Assuntos
Microbiota , Plantago/genética , Plantago/virologia , Coinfecção/virologia , Variação Genética , Genótipo , Interações Hospedeiro-Patógeno , Modelos Biológicos , Doenças das Plantas/virologia , Vírus de Plantas/classificação , Vírus de Plantas/genética , Vírus de Plantas/isolamento & purificação , Vírus de Plantas/fisiologia
4.
Arch Virol ; 165(12): 2807-2815, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32990842

RESUMO

Nicotiana benthamiana plants became infected with blueberry latent spherical virus (BLSV) after pollination with pollen grains produced by BLSV-infected N. benthamiana plants. Interestingly, pollen grains produced by BLSV-infected Vaccinium corymbosum (blueberry), Nicotiana alata, and Petunia × hybrida (petunia) plants also transmitted the virus to healthy N. benthamiana plants after pollination. As seen using aniline blue staining and fluorescence microscopy, pollen grains from BLSV-infected blueberry, N. alata, and petunia plants germinated on stigmas of N. benthamiana, and the pollen tubes penetrated the stigmas in a manner similar to that of N. benthamiana pollen grains on N. benthamiana stigmas. Whole-mount in situ hybridization and chromogenic in situ hybridization analysis showed that infected blueberry and N. benthamiana pollen grains germinated on N. benthamiana stigmas, and virus-containing pollen tubes penetrated the stigmas. Tissue blot hybridization analysis revealed that the initial infection sites were the N. benthamiana stigmas pollinated with infected pollen grains from blueberry and N. benthamiana. In addition, the virus spread from the initial infection sites to the phloem in the stigma and style. Taken together, we suggest that penetrating pollen tubes that harbored the virus results in infection foci in the stigma, and the virus then moves to the vascular tissues in the stigma and style and eventually establishes systemic infection.


Assuntos
Transmissão de Doença Infecciosa , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Tubo Polínico/virologia , Mirtilos Azuis (Planta)/virologia , Petunia/virologia , Tabaco/virologia
5.
Nat Commun ; 11(1): 4626, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934228

RESUMO

The blooming cosmopolitan coccolithophore Emiliania huxleyi and its viruses (EhVs) are a model for density-dependent virulent dynamics. EhVs commonly exhibit rapid viral reproduction and drive host death in high-density laboratory cultures and mesocosms that simulate blooms. Here we show that this system exhibits physiology-dependent temperate dynamics at environmentally relevant E. huxleyi host densities rather than virulent dynamics, with viruses switching from a long-term non-lethal temperate phase in healthy hosts to a lethal lytic stage as host cells become physiologically stressed. Using this system as a model for temperate infection dynamics, we present a template to diagnose temperate infection in other virus-host systems by integrating experimental, theoretical, and environmental approaches. Finding temperate dynamics in such an established virulent host-virus model system indicates that temperateness may be more pervasive than previously considered, and that the role of viruses in bloom formation and decline may be governed by host physiology rather than by host-virus densities.


Assuntos
Haptófitas/virologia , Vírus de Plantas/fisiologia , Vírus de Plantas/patogenicidade , Haptófitas/fisiologia , Interações Hospedeiro-Patógeno , Modelos Biológicos , Virulência
6.
PLoS Pathog ; 16(7): e1008709, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32730331

RESUMO

Nine genera of viruses in five different families use triple gene block (TGB) proteins for virus movement. The TGB modules fall into two classes: hordei-like and potex-like. Although TGB-mediated viral movement has been extensively studied, determination of the constituents of the viral ribonucleoprotein (vRNP) movement complexes and the mechanisms underlying their involvement in vRNP-mediated movement are far from complete. In the current study, immunoprecipitation of TGB1 protein complexes formed during Barley stripe mosaic virus (BSMV) infection revealed the presence of the γb protein in the products. Further experiments demonstrated that TGB1 interacts with γb in vitro and in vivo, and that γb-TGB1 localizes at the periphery of chloroplasts and plasmodesmata (PD). Subcellular localization analyses of the γb protein in Nicotiana benthamiana epidermal cells indicated that in addition to chloroplast localization, γb also targets the ER, actin filaments and PD at different stages of viral infection. By tracking γb localization during BSMV infection, we demonstrated that γb is required for efficient cell-to-cell movement. The N-terminus of γb interacts with the TGB1 ATPase/helicase domain and enhances ATPase activity of the domain. Inactivation of the TGB1 ATPase activity also significantly impaired PD targeting. In vitro translation together with co-immunoprecipitation (co-IP) analyses revealed that TGB1-TGB3-TGB2 complex formation is enhanced by ATP hydrolysis. The γb protein positively regulates complex formation in the presence of ATP, suggesting that γb has a novel role in BSMV cell-to-cell movement by directly promoting TGB1 ATPase-mediated vRNP movement complex assembly. We further demonstrated that elimination of ATPase activity abrogates PD and actin targeting of Potato virus X (PVX) and Beet necrotic yellow vein virus (BNYVV) TGB1 proteins. These results expand our understanding of the multifunctional roles of γb and provide new insight into the functions of TGB1 ATPase domains in the movement of TGB-encoding viruses.


Assuntos
Proteínas do Movimento Viral em Plantas/metabolismo , Vírus de Plantas/fisiologia , Proteínas de Ligação a RNA/metabolismo , Tabaco/virologia , Proteínas não Estruturais Virais/metabolismo , Montagem de Vírus/fisiologia , Adenosina Trifosfatases/metabolismo , Potexvirus/fisiologia , Ribonucleoproteínas/metabolismo
7.
PLoS One ; 15(6): e0221834, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589631

RESUMO

To unravel the virome in birch trees of German and Finnish origin exhibiting symptoms of birch leaf-roll disease (BRLD), high-throughput sequencing (HTS) was employed. In total five viruses, among which three were so far unknown, were detected by RNAseq. One to five virus variants were identified in the transcriptome of individual trees. The novel viruses were genetically-fully or partially-characterized, belonging to the genera Carlavirus, Idaeovirus and Capillovirus and are tentatively named birch carlavirus, birch idaeovirus, and birch capillovirus, respectively. The recently discovered birch leafroll-associated virus was systematically detected by HTS in symptomatic seedlings but not in symptomless ones. The new carlavirus was detected only in one of the three symptomatic seedlings. The novel putative Capillovirus was detected in all seedlings-irrespective of their BLRD status-while the Idaeovirus was identified in a plant without leaf symptoms at the time of sampling. Further efforts are needed to complete Koch's postulates and to clarify the possible association of the detected viruses with the BLR disease. Our study elucidates the viral population in single birch seedlings and provides a comprehensive overview for the diversities of the viral communities they harbor, to date.


Assuntos
Betula/virologia , Vírus de Plantas/genética , RNA-Seq , Metagenômica , Filogenia , Vírus de Plantas/fisiologia
8.
Sci Rep ; 10(1): 7649, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32376869

RESUMO

Plant viruses rely on insect vectors for transmission among plant hosts, but many of the specifics of virus-vector interactions are not fully understood. Thrips tabaci, which transmits Tomato spotted wilt virus (TSWV) in a persistent and propagative manner, varies greatly in its ability to transmit different isolates of TSWV. Similarly, TSWV isolates are transmitted at different efficiencies by different populations of T. tabaci. This study characterizes differences in virus titers in the vector among TSWV isolate-T. tabaci isoline pairings in relation to differences in transmission rates, and demonstrates that although transmission rates were higher for sympatric than allopatric TSWV isolate-T. tabaci isoline pairings, virus titers in the thrips vector were significantly lower in the sympatric pairings. Results further demonstrate that TSWV titers in the vector were unrelated to virus titers in the leaf tissue from which they acquired the virus and provide evidence for the importance of specific vector-virus interactions and local adaptation in determining transmission efficiency of TSWV by T. tabaci.


Assuntos
Insetos Vetores/virologia , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Carga Viral , Animais , Tospovirus
9.
Proc Natl Acad Sci U S A ; 117(20): 10848-10855, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32371486

RESUMO

Grapevine fanleaf virus (GFLV) is a picorna-like plant virus transmitted by nematodes that affects vineyards worldwide. Nanobody (Nb)-mediated resistance against GFLV has been created recently, and shown to be highly effective in plants, including grapevine, but the underlying mechanism is unknown. Here we present the high-resolution cryo electron microscopy structure of the GFLV-Nb23 complex, which provides the basis for molecular recognition by the Nb. The structure reveals a composite binding site bridging over three domains of one capsid protein (CP) monomer. The structure provides a precise mapping of the Nb23 epitope on the GFLV capsid in which the antigen loop is accommodated through an induced-fit mechanism. Moreover, we uncover and characterize several resistance-breaking GFLV isolates with amino acids mapping within this epitope, including C-terminal extensions of the CP, which would sterically interfere with Nb binding. Escape variants with such extended CP fail to be transmitted by nematodes linking Nb-mediated resistance to vector transmission. Together, these data provide insights into the molecular mechanism of Nb23-mediated recognition of GFLV and of virus resistance loss.


Assuntos
Nepovirus/efeitos dos fármacos , Doenças das Plantas/imunologia , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/farmacologia , Animais , Anticorpos Antivirais/imunologia , Capsídeo/química , Proteínas do Capsídeo/química , Proteínas do Capsídeo/efeitos dos fármacos , Microscopia Crioeletrônica , Epitopos/química , Modelos Moleculares , Nematoides/virologia , Nepovirus/ultraestrutura , Doenças das Plantas/virologia , Folhas de Planta/virologia , Vírus de Plantas/imunologia , Vírus de Plantas/fisiologia , Conformação Proteica , Vitis
10.
PLoS One ; 15(4): e0231886, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32320461

RESUMO

Cotton leaf curl disease (CLCuD), caused by whitefly (Bemisiatabaci) transmitted single-stranded DNA viruses belonging to the Genus, Begomovirus (family, Geminiviridae) in association with satellite molecules; is responsible for major economic losses in cotton in three northwest (NW) Indian states Haryana, Punjab, and Rajasthan. Annual CLCuD incidences during 2012 to 2014 were estimated to be 37.5%, 63.6%, and 38.8% respectively. Cotton leaves were collected from symptomatic plants annually for three years and subjected to DNA isolation, followed by rolling circle amplification (RCA), cloning, and DNA sequencing of apparently full-length begomoviral genomes and associated betasatellites and alphasatellites. Among the thirteen CLCuD-begomoviral genomes recovered, eight were identified as Cotton leaf curl Multan virus-Rajasthan (CLCuMuV-Ra), one as -Pakistan (PK) and another as -Faisalabad (Fai), whereas, three were as Cotton leaf curl Kokhran virus-Burewala (CLCuKoV-Bu), indicating that CLCuMuV-Ra was the most prevalent begomovirus species. Five of the eight CLCuMuV-Ra sequences were found to be recombinants. The CLCuMuV-Ra- associated satellites consisted of Cotton leaf curl Multan betasatellite (CLCuMB), and Gossypium darwinii symptomless alphasatellite (GDarSLA), and Croton yellow vein mosaic alphasatellite (CrYVMoA). The second most abundant helper virus species, CLCuKoV-Bu, was associated with CLCuMB and GDarSLA.


Assuntos
DNA Recombinante/genética , Surtos de Doenças , Gossypium/virologia , Doenças das Plantas/virologia , Vírus de Plantas/genética , Vírus de Plantas/fisiologia , Evolução Molecular , Índia
11.
J Insect Sci ; 20(2)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32282036

RESUMO

We report a new positive-sense single-stranded RNA (ss RNA+) virus from the brown citrus aphid Aphis citricidus. The 20,300 nucleotide (nt)-long viral genome contains five open-reading frames and encodes six conserved domains (TM2, 3CLpro, TM3, RdRp, Zm, and HEL1). Phylogenetic analysis and amino acid sequence analysis revealed this virus might belong to an unassigned genus in the family Mesoniviridae. The presence of the virus was also confirmed in the field population. Importantly, analysis of the virus-derived small RNAs showed a 22-nt peak, implying that viral infection triggers the small interfering RNA pathway as antiviral immunity in aphids. This is the first report of a mesonivirus in invertebrates other than mosquitoes.


Assuntos
Afídeos/virologia , Especificidade de Hospedeiro , Nidovirales/fisiologia , RNA Viral/análise , Animais , Afídeos/crescimento & desenvolvimento , Ninfa/crescimento & desenvolvimento , Ninfa/virologia , Vírus de Plantas/fisiologia , Análise de Sequência de RNA
12.
Proc Natl Acad Sci U S A ; 117(7): 3779-3788, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32015104

RESUMO

Plants and fungi are closely associated through parasitic or symbiotic relationships in which bidirectional exchanges of cellular contents occur. Recently, a plant virus was shown to be transmitted from a plant to a fungus, but it is unknown whether fungal viruses can also cross host barriers and spread to plants. In this study, we investigated the infectivity of Cryphonectria hypovirus 1 (CHV1, family Hypoviridae), a capsidless, positive-sense (+), single-stranded RNA (ssRNA) fungal virus in a model plant, Nicotiana tabacum CHV1 replicated in mechanically inoculated leaves but did not spread systemically, but coinoculation with an unrelated plant (+)ssRNA virus, tobacco mosaic virus (TMV, family Virgaviridae), or other plant RNA viruses, enabled CHV1 to systemically infect the plant. Likewise, CHV1 systemically infected transgenic plants expressing the TMV movement protein, and coinfection with TMV further enhanced CHV1 accumulation in these plants. Conversely, CHV1 infection increased TMV accumulation when TMV was introduced into a plant pathogenic fungus, Fusarium graminearum In the in planta F. graminearum inoculation experiment, we demonstrated that TMV infection of either the plant or the fungus enabled the horizontal transfer of CHV1 from the fungus to the plant, whereas CHV1 infection enhanced fungal acquisition of TMV. Our results demonstrate two-way facilitative interactions between the plant and fungal viruses that promote cross-kingdom virus infections and suggest the presence of plant-fungal-mediated routes for dissemination of fungal and plant viruses in nature.


Assuntos
Micovírus/fisiologia , Fusarium/virologia , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Vírus do Mosaico do Tabaco/fisiologia , Tabaco/virologia , Fusarium/fisiologia
13.
Phytopathology ; 110(1): 6-9, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910089

RESUMO

Given the importance of and rapid research progress in plant virology in recent years, this Focus Issue broadly emphasizes advances in fundamental aspects of virus infection cycles and epidemiology. This Focus Issue comprises three review articles and 18 research articles. The research articles cover broad research areas on the identification of novel viruses, the development of detection methods, reverse genetics systems and functional genomics for plant viruses, vector and seed transmission studies, viral population studies, virus-virus interactions and their effect on vector transmission, and management strategies of viral diseases. The three review articles discuss recent developments in application of prokaryotic clustered regularly interspaced short palindromic repeats/CRISPR-associated genes (CRISPR/Cas) technology for plant virus resistance, mixed viral infections and their role in disease synergism and cross-protection, and viral transmission by whiteflies. The following briefly summarizes the articles appearing in this Focus Issue.


Assuntos
Patologia Vegetal , Vírus de Plantas , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia
14.
Nat Commun ; 11(1): 495, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980630

RESUMO

Maize rough dwarf disease (MRDD), caused by various species of the genus Fijivirus, threatens maize production worldwide. We previously identified a quantitative locus qMrdd1 conferring recessive resistance to one causal species, rice black-streaked dwarf virus (RBSDV). Here, we show that Rab GDP dissociation inhibitor alpha (RabGDIα) is the host susceptibility factor for RBSDV. The viral P7-1 protein binds tightly to the exon-10 and C-terminal regions of RabGDIα to recruit it for viral infection. Insertion of a helitron transposon into RabGDIα intron 10 creates alternative splicing to replace the wild-type exon 10 with a helitron-derived exon 10. The resultant splicing variant RabGDIα-hel has difficulty being recruited by P7-1, thus leading to quantitative recessive resistance to MRDD. All naturally occurring resistance alleles may have arisen from a recent single helitron insertion event. These resistance alleles are valuable to improve maize resistance to MRDD and potentially to engineer RBSDV resistance in other crops.


Assuntos
Resistência à Doença , Inibidores de Dissociação do Nucleotídeo Guanina/metabolismo , Doenças das Plantas/virologia , Proteínas de Plantas/metabolismo , Vírus de Plantas/fisiologia , Zea mays/virologia , Alelos , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Inibidores de Dissociação do Nucleotídeo Guanina/genética , Modelos Biológicos , Mapeamento Físico do Cromossomo , Doenças das Plantas/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Locos de Características Quantitativas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Proteínas Virais/metabolismo , Zea mays/genética , Zea mays/ultraestrutura
15.
Arch Virol ; 165(1): 169-178, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31773326

RESUMO

Plant viruses can alter the behavior or performance of their arthropod vectors, either indirectly (through effects of virus infection on the host plant) or directly (from virus acquisition by the vector). Given the diversity of plant viruses and their arthropod vectors, the effects for any specific system are not possible to predict. Here, we present experimental evidence that acquisition of maize Iranian mosaic virus (MIMV, genus Nucleorhabdovirus, family Rhabdoviridae) modifies the biological traits of its insect vector, the small brown planthopper (SBPH) Laodelphax striatellus. MIMV is an economically important virus of maize and several other grass species. It is transmitted by SBPHs in a persistent-propagative manner. We evaluated the effects of MIMV acquisition by SBPH on its life history when reared on healthy barley plants (Hordeum vulgare). We conclude that 1) MIMV acquisition by SBPHs increases female fecundity, duration of the nymph stage, adult longevity, and survival of SBPHs, (2) the mortality rate and female-to-male sex ratio are reduced in MIMV-infected planthoppers, and (3) MIMV infection increases the concentration of some biochemical components of the infected plants, including carbohydrates, some amino acids, and total protein, which might influence the life traits of its insect vector. The results indicate the potential of MIMV to improve the ecological fitness of its vector, SBPH, through direct or indirect effects, with the potential to increase the spread of the virus.


Assuntos
Hemípteros/fisiologia , Rhabdoviridae/fisiologia , Zea mays/metabolismo , Zea mays/virologia , Aminoácidos/metabolismo , Animais , Metabolismo dos Carboidratos , Feminino , Fertilidade , Hemípteros/virologia , Insetos Vetores/fisiologia , Insetos Vetores/virologia , Longevidade , Masculino , Proteínas de Plantas/metabolismo , Vírus de Plantas/fisiologia
16.
Mol Plant Microbe Interact ; 33(1): 18-25, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31729283

RESUMO

Plant viruses typically cause severe pathogenicity in plants, even resulting in the death of plants. Many pathogenic plant viruses are transmitted in a persistent manner via insect vectors. Interestingly, unlike in the plant hosts, persistent viruses are either nonpathogenic or show limited pathogenicity in their insect vectors, while taking advantage of the cellular machinery of insect vectors for completing their life cycles. This review discusses why persistent plant viruses are nonpathogenic or have limited pathogenicity to their insect vectors while being pathogenic to plants hosts. Current advances in cell biology of virus-insect vector interactions are summarized, including virus-induced inclusion bodies, changes of insect cellular ultrastructure, and immune response of insects to the viruses, especially autophagy and apoptosis. The corresponding findings of virus-plant interactions are compared. An integrated view of the balance strategy achieved by the interaction between viral attack and the immune response of insect is presented. Finally, we outline progress gaps between virus-insect and virus-plant interactions, thus highlighting the contributions of cultured cells to the cell biology of virus-insect interactions. Furthermore, future prospects of studying the cell biology of virus-vector interactions are presented.


Assuntos
Interações Hospedeiro-Patógeno , Insetos Vetores , Vírus de Plantas , Plantas , Animais , Insetos Vetores/virologia , Células Vegetais/virologia , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Plantas/virologia
17.
Virus Genes ; 56(1): 104-107, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31745745

RESUMO

Soybean vein necrosis virus (SVNV), the causal agent of the homonymous disease, is a ubiquitous virus in North America. The widespread presence of the virus has led to the hypothesis that mixed infections with other viruses could alter disease symptoms, localization in the plant and even epidemiology. The potential interaction between bean pod mottle virus (BPMV), soybean mosaic virus (SMV), the most economically important soybean viruses in the U.S., and SVNV was assessed in the work presented here. Results revealed that soybean, a local lesion host for SVNV, becomes permissive in the presence of BPMV; whereas there where no obvious interactions observed in mixed infections with SMV.


Assuntos
Comovirus/fisiologia , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Soja/virologia , Vírus de Plantas/genética , Potyvirus/fisiologia
18.
Arch Virol ; 165(1): 11-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31620899

RESUMO

Southern tomato virus (STV) is often found infecting healthy tomato plants (Solanum lycopersicum). In this study, we compared STV-free and STV-infected plants of cultivar M82 to determine the effect of STV infection on the host plant. STV-free plants exhibited a short and bushy phenotype, whereas STV-infected plants were taller. STV-infected plants produced more fruit than STV-free plants, and the germination rate of seeds from STV-infected plants was higher than that of seeds from STV-free plants. This phenotypic difference was also observed in progeny plants (siblings) derived from a single STV-infected plant in which the transmission rate of STV to progeny plants via the seeds was approximately 86%. These results suggest that the interaction between STV and host plants is mutualistic. Transcriptome analysis revealed that STV infection affects gene expression in the host plant and results in downregulation of genes involved in ethylene biosynthesis and signaling. STV-infected tomato plants might thus be artificially selected due to their superior traits as a crop.


Assuntos
Perfilação da Expressão Gênica/métodos , Lycopersicon esculentum/crescimento & desenvolvimento , Proteínas de Plantas/genética , Vírus de Plantas/fisiologia , Infecções Assintomáticas , Etilenos/biossíntese , Frutas/crescimento & desenvolvimento , Frutas/virologia , Regulação da Expressão Gênica de Plantas , Germinação , Lycopersicon esculentum/genética , Lycopersicon esculentum/virologia , Fenótipo , Transdução de Sinais , Simbiose
19.
Phytopathology ; 110(1): 94-105, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31589103

RESUMO

Increasing evidence indicates that in wild ecosystems plant viruses are important ecological agents, and with potential to jump into crops, but only recently have the diversity and population dynamics of wild plant viruses begun to be explored. Theory proposes that biotic factors (e.g., ecosystem biodiversity, host abundance, and host density) and climatic conditions would determine the epidemiology and evolution of wild plant viruses. However, these predictions seldom have been empirically tested. For 3 years, we analyzed the prevalence and genetic diversity of Potyvirus species in preserved riparian forests of Spain. Results indicated that potyviruses were always present in riparian forests, with a novel generalist potyvirus species provisionally named Iberian hop mosaic virus (IbHMV), explaining the largest fraction of infected plants. Focusing on this potyvirus, we analyzed the biotic and climatic factors affecting virus infection risk and population genetic diversity in its native ecosystem. The main predictors of IbHMV infection risk were host relative abundance and species richness. Virus prevalence and host relative abundance were the major factors determining the genetic diversity and selection pressures in the virus population. These observations support theoretical predictions assigning these ecological factors a key role in parasite epidemiology and evolution. Finally, our phylogenetic analysis indicated that the viral population was genetically structured according to host and location of origin, as expected if speciation is largely sympatric. Thus, this work contributes to characterizing viral diversity and provides novel information on the determinants of plant virus epidemiology and evolution in wild ecosystems.


Assuntos
Ecossistema , Interações Hospedeiro-Patógeno , Doenças das Plantas , Vírus de Plantas , Plantas , Potyvirus , Especificidade de Hospedeiro , Interações Hospedeiro-Patógeno/fisiologia , Filogenia , Doenças das Plantas/virologia , Vírus de Plantas/classificação , Vírus de Plantas/fisiologia , Plantas/virologia , Densidade Demográfica , Potyvirus/classificação , Potyvirus/genética , Espanha
20.
Mol Plant Microbe Interact ; 33(1): 26-39, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31715107

RESUMO

Plasmodesmata (PD) are essential for intercellular trafficking of molecules required for plant life, from small molecules like sugars and ions to macromolecules including proteins and RNA molecules that act as signals to regulate plant development and defense. As obligate intracellular pathogens, plant viruses have evolved to manipulate this communication system to facilitate the initial cell-to-cell and eventual systemic spread in their plant hosts. There has been considerable interest in how viruses manipulate the PD that connect the protoplasts of neighboring cells, and viruses have yielded invaluable tools for probing the structure and function of PD. With recent advances in biochemistry and imaging, we have gained new insights into the composition and structure of PD in the presence and absence of viruses. Here, we first discuss viral strategies for manipulating PD for their intercellular movement and examine how this has shed light on our understanding of native PD function. We then address the controversial role of the cytoskeleton in trafficking to and through PD. Finally, we address how viruses could alter PD structure and consider possible mechanisms of the phenomenon described as 'gating'. This discussion supports the significance of virus research in elucidating the properties of PD, these persistently enigmatic plant organelles.


Assuntos
Vírus de Plantas , Plasmodesmos , Citoesqueleto/metabolismo , Desenvolvimento Vegetal/fisiologia , Vírus de Plantas/fisiologia , Plantas/virologia , Plasmodesmos/virologia , Transporte Proteico/fisiologia , Transdução de Sinais
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