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1.
PLoS Pathog ; 17(10): e1009915, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34618877

RESUMO

The fast-paced evolution of viruses enables them to quickly adapt to the organisms they infect by constantly exploring the potential functional landscape of the proteins encoded in their genomes. Geminiviruses, DNA viruses infecting plants and causing devastating crop diseases worldwide, produce a limited number of multifunctional proteins that mediate the manipulation of the cellular environment to the virus' advantage. Among the proteins produced by the members of this family, C4, the smallest one described to date, is emerging as a powerful viral effector with unexpected versatility. C4 is the only geminiviral protein consistently subjected to positive selection and displays a number of dynamic subcellular localizations, interacting partners, and functions, which can vary between viral species. In this review, we aim to summarize our current knowledge on this remarkable viral protein, encompassing the different aspects of its multilayered diversity, and discuss what it can teach us about geminivirus evolution, invasion requirements, and virulence strategies.


Assuntos
Geminiviridae/fisiologia , Geminiviridae/patogenicidade , Proteínas Virais/metabolismo , Evolução Molecular , Doenças das Plantas/genética , Virulência
2.
Biochemistry ; 60(37): 2795-2809, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34464102

RESUMO

The geminivirus replication protein, Rep, has long been recognized as a high-value target for control of geminivirus infections as this protein is highly conserved and essential for viral replication and proliferation. In addition, inhibition of viral replication has been pursued through various antiviral strategies with varying degrees of success, including inhibitory peptides that target Rep. While much effort has centered around sequence characterization of the Rep protein and inhibitory peptides, detailed structural analysis has been missing. This study computationally investigated the presence of common structural features within these inhibitory peptides and if these features could inform if a particular peptide will bind Rep and/or interfere with viral replication. Molecular dynamics simulations of the inhibitory peptide library showed that simply possessing stable structural features does not inform interference of viral replication regardless of the binding of Rep. Additionally, nearly all known Rep inhibitory peptides sample a conserved ß-sheet structural motif, possibly informing structure-function relationships in binding Rep. In particular, two peptides (A22 and A64) characterized by this structural motif were computationally docked against a wide variety of geminivirus Rep proteins to determine a mechanism of action. Computational docking revealed these peptides utilize a common Rep protein sequence motif for binding, HHN-x1/2-Q. The results identified residues in both Rep and the inhibitory peptides that play a significant role in the interaction, establishing the foundation for a rational structure-based design approach for the construction of both broadly reactive and geminivirus species-specific inhibitors.


Assuntos
Geminiviridae/enzimologia , Geminiviridae/metabolismo , Replicação Viral/fisiologia , Motivos de Aminoácidos/genética , Sequência de Aminoácidos/genética , DNA Helicases/metabolismo , DNA Viral/metabolismo , Geminiviridae/genética , Peptídeos/metabolismo , Ligação Proteica/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas Virais/ultraestrutura , Replicação Viral/genética
3.
Nat Commun ; 12(1): 4278, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257307

RESUMO

Geminiviruses are plant viruses with limited coding capacity. Geminivirus-encoded proteins are traditionally identified by applying a 10-kDa arbitrary threshold; however, it is increasingly clear that small proteins play relevant roles in biological systems, which calls for the reconsideration of this criterion. Here, we show that geminiviral genomes contain additional ORFs. Using tomato yellow leaf curl virus, we demonstrate that some of these small ORFs are expressed during the infection, and that the encoded proteins display specific subcellular localizations. We prove that the largest of these additional ORFs, which we name V3, is required for full viral infection, and that the V3 protein localizes in the Golgi apparatus and functions as an RNA silencing suppressor. These results imply that the repertoire of geminiviral proteins can be expanded, and that getting a comprehensive overview of the molecular plant-geminivirus interactions will require the detailed study of small ORFs so far neglected.


Assuntos
Begomovirus/patogenicidade , Geminiviridae/genética , Geminiviridae/patogenicidade , Genoma Viral/genética , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/fisiologia , Fases de Leitura Aberta/genética , Doenças das Plantas/virologia , Interferência de RNA/fisiologia , Tabaco/ultraestrutura , Proteínas Virais/genética , Proteínas Virais/metabolismo , Virulência
4.
Arch Virol ; 166(9): 2573-2578, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34148142

RESUMO

A novel geminivirus was identified in France and Spain in asymptomatic plants of white clover (Trifolium repens) and shrub medick (Medicago arborea). Its genome has the hallmarks of a capulavirus, and its relationship to other capulaviruses was confirmed by phylogenetic analysis. White clover isolates formed a tight cluster in the phylogenetic tree, while shrub medick isolates formed two distinct, more divergent groups with sequence identity values close to the species cutoff. These three groups have likely participated in recombination events involving alfalfa leaf curl virus and French bean severe leaf curl virus. The name "trifolium virus 1" (TrV1) is proposed for this new Capulavirus. Three TrV1 genotypes (TrV1-A, TrV1-B, and TrV1-C) were clearly distinguished.


Assuntos
Filogenia , Trifolium/virologia , Vírus não Classificados/classificação , Vírus não Classificados/genética , Vírus não Classificados/isolamento & purificação , Sequência de Aminoácidos , Biodiversidade , Vírus de DNA/genética , Fabaceae/virologia , Geminiviridae/classificação , Geminiviridae/genética , Geminiviridae/isolamento & purificação , Genótipo , Fases de Leitura Aberta , Doenças das Plantas/virologia , Análise de Sequência de DNA
5.
J Econ Entomol ; 114(4): 1462-1469, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34132345

RESUMO

Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease, which affects wine grapes and leads to reduced crop yield and quality. The pathogen-plant-vector relationship of GRBV is not well understood; however, some possible vectors have been identified: Caladonus coquilletti (Van Duzee; Hemiptera: Cicadellidae), Colladonus reductus (Van Duzee; Hemiptera: Cicadellidae), Erythroneura spp., Melanoliarus sp. (Hemiptera: Cixiidae), Osbornellus borealis DeLong. & Mohr (Hemiptera: Cicadellidae), Scaphytopius granticus (Ball; Hemiptera: Cicadellidae), Spissistilus festinus (Say). Of these species, S. festinus has been shown to transmit the virus to uninfected grapevines, making it of particular interest. Since the pathogen-plant-vector relationship of GRBV is not yet completely understood, pesticide use is not necessarily the best way to manage these possible vectors. Here we test if ground cover removal, by discing in spring, could reduce the activity of potential GRBV vectors. We show that S. festinus presence in the canopy was reduced in disc rows compared to just mowing the ground vegetation, whereas there were no differences in presence in the canopy between disc and mow rows of the other possible insect vectors. Erythroneura elegantula (Osborn; Hemiptera: Cicadellidae), a common pest of grapevines but not a candidate GRBV vector, was found to have higher densities in the canopy in disc rows compared to mow rows, an effect possibly mediated by changes in vine vigor associated with ground covers. We conclude that if S. festinus is a primary vector of GRBV, discing ground covers in early spring may be a viable way to reduce their presence in the vine canopy.


Assuntos
Geminiviridae , Hemípteros , Vitis , Animais , Medicago sativa , Doenças das Plantas
6.
J Virol ; 95(17): e0026421, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34132570

RESUMO

Uncharacterized viral genomes that encode circular replication-associated proteins of single-stranded DNA viruses have been discovered by metagenomics/metatranscriptomics approaches. Some of these novel viruses are classified in the newly formed family Genomoviridae. Here, we determined the host range of a novel genomovirus, SlaGemV-1, through the transfection of Sclerotinia sclerotiorum with infectious clones. Inoculating with the rescued virions, we further transfected Botrytis cinerea and Monilinia fructicola, two economically important members of the family Sclerotiniaceae, and Fusarium oxysporum. SlaGemV-1 causes hypovirulence in S. sclerotiorum, B. cinerea, and M. fructicola. SlaGemV-1 also replicates in Spodoptera frugiperda insect cells but not in Caenorhabditis elegans or plants. By expressing viral genes separately through site-specific integration, the replication protein alone was sufficient to cause debilitation. Our study is the first to demonstrate the reconstruction of a metagenomically discovered genomovirus without known hosts with the potential of inducing hypovirulence, and the infectious clone allows for studying mechanisms of genomovirus-host interactions that are conserved across genera. IMPORTANCE Little is known about the exact host range of widespread genomoviruses. The genome of soybean leaf-associated gemygorvirus-1 (SlaGemV-1) was originally assembled from a metagenomic/metatranscriptomic study without known hosts. Here, we rescued SlaGemV-1 and found that it could infect three important plant-pathogenic fungi and fall armyworm (S. frugiperda Sf9) insect cells but not a model nematode, C. elegans, or model plant species. Most importantly, SlaGemV-1 shows promise for inducing hypovirulence of the tested fungal species in the family Sclerotiniaceae, including Sclerotinia sclerotiorum, Botrytis cinerea, and Monilinia fructicola. The viral determinant of hypovirulence was further identified as replication initiation protein. As a proof of concept, we demonstrate that viromes discovered in plant metagenomes can be a valuable genetic resource when novel viruses are rescued and characterized for their host range.


Assuntos
Ascomicetos/virologia , Geminiviridae/isolamento & purificação , Especificidade de Hospedeiro , Metagenoma , Doenças das Plantas/prevenção & controle , Tabaco/crescimento & desenvolvimento , Virulência , Animais , Ascomicetos/genética , Ascomicetos/patogenicidade , Botrytis/genética , Botrytis/patogenicidade , Botrytis/virologia , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/microbiologia , Caenorhabditis elegans/virologia , Fusarium/genética , Fusarium/patogenicidade , Fusarium/virologia , Geminiviridae/classificação , Geminiviridae/genética , Genoma Viral , Controle Biológico de Vetores , Doenças das Plantas/microbiologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Folhas de Planta/virologia , Soja/crescimento & desenvolvimento , Soja/microbiologia , Tabaco/microbiologia , Tabaco/virologia , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vírion
7.
J Virol ; 95(17): e0047521, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34132576

RESUMO

Plant virus satellites are maintained by their associated helper viruses, and satellites influence viral pathogenesis. Diseases caused by geminivirus-betasatellite complexes can become epidemics and therefore have become a threat to economically important crops across the world. Here, we identified a novel molecular function of the betasatellite-encoded pathogenicity determinant ßC1. The tomato leaf curl Patna betasatellite (ToLCPaB)-encoded ßC1 protein was found to exhibit novel ATPase activity in the presence of the divalent metal ion cofactor MgCl2. Moreover, ATPase activity was confirmed to be ubiquitously displayed by ßC1 proteins encoded by diverse betasatellites. Mutational and sequence analysis showed that conserved lysine/arginine residues at positions 49/50 and 91 of ßC1 proteins are essential for their ATPase activity. Biochemical studies revealed that the DNA-binding activity of the ßC1 protein was interfered with by the binding of ATP to the protein. Mutating arginine 91 of ßC1 to alanine reduced its DNA-binding activity. The results of docking studies provided evidence for an overlap of the ATP-binding and DNA-binding regions of ßC1 and for the importance of arginine 91 for both ATP-binding and DNA-binding activities. A mutant betasatellite with a specifically ßC1-ATPase dominant negative mutation was found to induce symptoms on Nicotiana benthamiana plants similar to those induced by wild-type betasatellite infection. The ATPase function of ßC1 was found to be negatively associated with geminivirus-betasatellite DNA accumulation, despite the positive influence of this ATPase function on the accumulation of replication-associated protein (Rep) and ßC1 transcripts. IMPORTANCE Most satellites influence the pathogenesis of their helper viruses. Here, we characterized the novel molecular function of ßC1, a nonstructural pathogenicity determinant protein encoded by a betasatellite. We demonstrated the display of ATPase activity by this ßC1 protein. Additionally, we confirmed the ubiquitous display of ATPase activity by ßC1 proteins encoded by diverse betasatellites. The lysine/arginine residues conserved at positions 49 and 91 of ßC1 were found to be crucial for its ATPase function. DNA-binding activity of ßC1 was found to be reduced in the presence of ATP. Inhibition of ATPase activity of ßC1 in the presence of an excess concentration of cold ATP, GTP, CTP, or UTP suggested that the purified ßC1 can also hydrolyze other cellular nucleoside triphosphates (NTPs) besides ATP in vitro. These results established the importance of the ATPase and DNA-binding activities of the ßC1 protein in regulating geminivirus-betasatellite DNA accumulation in the infected plant cell.


Assuntos
Trifosfato de Adenosina/metabolismo , DNA Satélite/metabolismo , Geminiviridae/patogenicidade , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Proteínas de Plantas/metabolismo , Proteínas Virais/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , DNA Satélite/genética , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Hidrólise , Mutação , Folhas de Planta/virologia , Proteínas de Plantas/genética , Tabaco/virologia , Proteínas Virais/genética
8.
Sci Rep ; 11(1): 11150, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-34045539

RESUMO

Viruses within the Geminiviridae family cause extensive agricultural losses. Members of four genera of geminiviruses contain a C4 gene (AC4 in geminiviruses with bipartite genomes). C4(AC4) genes are entirely overprinted on the C1(AC1) genes, which encode the replication-associated proteins. The C4(AC4) proteins exhibit diverse functions that may be important for geminivirus diversification. In this study, the influence of natural selection on the evolutionary diversity of 211 C4(AC4) genes relative to the C1(AC1) sequences they overlap was determined from isolates of the Begomovirus and Curtovirus genera. The ratio of nonsynonymous (dN) to synonymous (dS) nucleotide substitutions indicated that C4(AC4) genes are under positive selection, while the overlapped C1(AC1) sequences are under purifying selection. Ninety-one of 200 Begomovirus C4(AC4) genes encode elongated proteins with the extended regions being under neutral selection. C4(AC4) genes from begomoviruses isolated from tomato from native versus exotic regions were under similar levels of positive selection. Analysis of protein structure suggests that C4(AC4) proteins are entirely intrinsically disordered. Our data suggest that non-synonymous mutations and mutations that increase the length of C4(AC4) drive protein diversity that is intrinsically disordered, which could explain C4/AC4 functional variation and contribute to both geminivirus diversification and host jumping.


Assuntos
Begomovirus/genética , Geminiviridae/genética , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Proteínas Virais/genética
9.
Nat Commun ; 12(1): 2780, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33986276

RESUMO

Geminiviruses are causal agents of devastating diseases in crops. Geminiviruses have circular single-stranded (ss) DNA genomes that are replicated in the nucleus of the infected plant cell through double-stranded (ds) DNA intermediates by the plant DNA replication machinery. Which host DNA polymerase mediates geminiviral multiplication, however, has so far remained elusive. Here, we show that subunits of the nuclear replicative DNA polymerases α and δ physically interact with the geminivirus-encoded replication enhancer protein, C3, and that these polymerases are required for viral replication. Our results suggest that, while DNA polymerase α is essential to generate the viral dsDNA intermediate, DNA polymerase δ mediates the synthesis of new copies of the geminiviral ssDNA genome, and that the virus-encoded C3 may act selectively, recruiting DNA polymerase δ over ε to favour productive replication.


Assuntos
DNA Polimerase III/metabolismo , DNA Polimerase I/metabolismo , Replicação do DNA/genética , DNA Viral/biossíntese , Geminiviridae/genética , Replicação Viral/genética , Genoma Viral/genética , Plantas/virologia , Subunidades Proteicas/metabolismo , Proteínas Virais/metabolismo
10.
Viruses ; 13(4)2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923787

RESUMO

The family Cactaceae comprises a diverse group of typically succulent plants that are native to the American continent but have been introduced to nearly all other continents, predominantly for ornamental purposes. Despite their economic, cultural, and ecological importance, very little research has been conducted on the viral community that infects them. We previously identified a highly divergent geminivirus that is the first known to infect cacti. Recent research efforts in non-cultivated and asymptomatic plants have shown that the diversity of this viral family has been under-sampled. As a consequence, little is known about the effects and interactions of geminiviruses in many plants, such as cacti. With the objective to expand knowledge on the diversity of geminiviruses infecting cacti, we used previously acquired high-throughput sequencing results to search for viral sequences using BLASTx against a viral RefSeq protein database. We identified two additional sequences with similarity to geminiviruses, for which we designed abutting primers and recovered full-length genomes. From 42 cacti and five scale insects, we derived 42 complete genome sequences of a novel geminivirus species that we have tentatively named Opuntia virus 2 (OpV2) and 32 genomes of an Opuntia-infecting becurtovirus (which is a new strain of the spinach curly top Arizona virus species). Interspecies recombination analysis of the OpV2 group revealed several recombinant regions, in some cases spanning half of the genome. Phylogenetic analysis demonstrated that OpV2 is a novel geminivirus more closely related to viruses of the genus Curtovirus, which was further supported by the detection of three recombination events between curtoviruses and OpV2. Both OpV2 and Opuntia becurtoviruses were identified in mixed infections, which also included the previously characterized Opuntia virus 1. Viral quantification of the co-infected cactus plants compared with single infections did not show any clear trend in viral dynamics that might be associated with the mixed infections. Using experimental Rhizobium-mediated inoculations, we found that the initial accumulation of OpV2 is facilitated by co-infection with OpV1. This study shows that the diversity of geminiviruses that infect cacti is under-sampled and that cacti harbor diverse geminiviruses. The detection of the Opuntia becurtoviruses suggests spill-over events between viruses of cultivated species and native vegetation. The threat this poses to cacti needs to be further investigated.


Assuntos
Cactaceae/virologia , Geminiviridae , Hemípteros/virologia , Doenças das Plantas/virologia , Animais , Geminiviridae/classificação , Geminiviridae/isolamento & purificação , Genoma Viral
11.
Viruses ; 13(3)2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33804134

RESUMO

In 2014, high-throughput sequencing of libraries of total DNA from olive trees allowed the identification of two geminivirus-like contigs. After conventional resequencing of the two genomic DNAs, their analysis revealed they belonged to the same viral entity, for which the provisional name of Olea europaea geminivirus (OEGV) was proposed. Although DNA-A showed a genome organization similar to that of New World begomoviruses, DNA-B had a peculiar ORF arrangement, consisting of a movement protein (MP) in the virion sense and a protein with unknown function on the complementary sense. Phylogenetic analysis performed either on full-length genome or on coat protein, replication associated protein (Rep), and MP sequences did not endorse the inclusion of this virus in any of the established genera in the family Geminiviridae. A survey of 55 plants revealed that the virus is widespread in Apulia (Italy) with 91% of the samples testing positive, although no correlation of OEGV with a disease or specific symptoms was encountered. Southern blot assay suggested that the virus is not integrated in the olive genome. The study of OEGV-derived siRNA obtained from small RNA libraries of leaves and fruits of three different cultivars, showed that the accumulation of the two genomic components is influenced by the plant genotype while virus-derived-siRNA profile is in line with other geminivirids reported in literature. Single-nucleotide polymorphism (SNP) analysis unveiled a low intra-specific variability.


Assuntos
Geminiviridae/classificação , Geminiviridae/patogenicidade , Genoma Viral , Olea/genética , Olea/virologia , Filogenia , Vírus de DNA/genética , Geminiviridae/genética , Geminiviridae/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Itália , Plantas/virologia , Vírion/genética , Vírion/isolamento & purificação
12.
BMC Genomics ; 22(1): 147, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33653270

RESUMO

BACKGROUND: The Beet curly top virus C4 oncoprotein is a pathogenic determinant capable of inducing extensive developmental abnormalities. No studies to date have investigated how the transcriptional profiles differ between plants expressing or not expressing the C4 oncoprotein. RESULTS: We investigated early transcriptional changes in Arabidopsis associated with expression of the Beet curly top virus C4 protein that represent initial events in pathogenesis via a comparative transcriptional analysis of mRNAs and small RNAs. We identified 48 and 94 differentially expressed genes at 6- and 12-h post-induction versus control plants. These early time points were selected to focus on direct regulatory effects of C4 expression. Since previous evidence suggested that the C4 protein regulated the brassinosteroid (BR)-signaling pathway, differentially expressed genes could be divided into two groups: those responsive to alterations in the BR-signaling pathway and those uniquely responsive to C4. Early transcriptional changes that disrupted hormone homeostasis, 18 and 19 differentially expressed genes at both 6- and 12-hpi, respectively, were responsive to C4-induced regulation of the BR-signaling pathway. Other C4-induced differentially expressed genes appeared independent of the BR-signaling pathway at 12-hpi, including changes that could alter cell development (4 genes), cell wall homeostasis (5 genes), redox homeostasis (11 genes) and lipid transport (4 genes). Minimal effects were observed on expression of small RNAs. CONCLUSION: This work identifies initial events in genetic regulation induced by a geminivirus C4 oncoprotein. We provide evidence suggesting the C4 protein regulates multiple regulatory pathways and provides valuable insights into the role of the C4 protein in regulating initial events in pathogenesis.


Assuntos
Geminiviridae , Tumores de Planta/virologia , Transcriptoma , Proteínas Virais , Geminiviridae/genética , Geminiviridae/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas Oncogênicas , Proteínas Virais/genética
13.
J Exp Bot ; 72(8): 2903-2917, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33577676

RESUMO

Geminiviruses can infect a wide range of plant hosts worldwide and have hence become an emerging global agroeconomic threat. The association of these viruses with satellite molecules and highly efficient insect vectors such as whiteflies further prime their devastating impacts. Plants elicit a strong antiviral immune response to restrict the invasion of these destructive pathogens. Phytohormones help plants to mount this response and occupy a key position in combating these biotrophs. These defense hormones not only inhibit geminiviral propagation but also hamper viral transmission by compromising the performance of their insect vectors. Nonetheless, geminiviruses have co-evolved to have a few multitasking virulence factors that readily remodel host cellular machineries to circumvent the phytohormone-mediated manifestation of the immune response. Furthermore, these obligate parasites exploit plant growth hormones to produce a cellular environment permissive for virus replication. In this review, we outline the current understanding of the roles and regulation of phytohormones in geminiviral pathogenesis.


Assuntos
Geminiviridae , Hemípteros , Animais , Doenças das Plantas , Reguladores de Crescimento de Plantas , Plantas
14.
Mol Biol (Mosk) ; 55(1): 96-106, 2021.
Artigo em Russo | MEDLINE | ID: mdl-33566029

RESUMO

Cotton leaf curl Multan betasatellite (CLCuMB) is a ubiquitous betasatellite commonly found along with cotton leaf curl disease (CLCuD) associated begomoviruses in the Old World. It has a promiscuous replicative nature and trans-replicated by a diverse range of geminiviruses. CLCuMB encodes a single ORF, ßCl, in the complementary direction and has pathogenicity, symptoms determinant, suppressor of post-transcription and transcription gene silencing functions. After substituting the ßC1 gene with the target gene, it has been used successfully as a gene delivery vector. In the present study, the ßC1 gene of CLCuMB was substituted with the green fluorescent protein (GFP) gene, and the resulting construct utilized as a reporter vector to decipher in planta localization of geminiviruses. The recombinant CLCuMB expressing GFP (CLCuMB-GFP) was co-inoculated to Nicotiana benthamiana plants either with Cotton leaf curl Kokharan virus (CLCuKoV) alone or in a combination with the wild type CLCuMB to investigate the objectives of the study. Results showed that CLCuKoV successfully supported the replication and systemic movement of CLCuMB-GFP either alone or in the presence of wild type CLCuMB. The presence of CLCuMB-GFP was readily detected with PCR and Southern blot hybridization. The modified CLCuMB may serve as a tool useful for in planta localization of geminiviruses.


Assuntos
Begomovirus , Geminiviridae , Begomovirus/genética , DNA Satélite/genética , Geminiviridae/genética , Doenças das Plantas/genética , Tabaco/genética , Virulência
15.
Sci Rep ; 11(1): 890, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441589

RESUMO

The leaf curl disease of Jatropha caused by geminiviruses results in heavy economic losses. In the present study, we report the identification of a new strain of a Jatropha leaf curl Gujarat virus (JLCuGV), which encodes six ORFs with each one having RNA silencing suppressor activity. Therefore, three artificial microRNAs (amiRNAs; C1/C4, C2/C3 and V1/V2) were designed employing overlapping regions, each targeting two ORFs of JLCuGV genomic DNA and transformed in tobacco. The C1/C4 and C2/C3 amiRNA transgenics were resistant while V1/V2 amiRNA transgenics were tolerant against JLCuGV. The relative level of amiRNA inversely related to viral load indicating a correlation with disease resistance. The assessment of photosynthetic parameters suggests that the transgenics perform significantly better in response to JLCuGV infiltration as compared to wild type (WT). The metabolite contents were not altered remarkably in amiRNA transgenics, but sugar metabolism and tricarboxylic acid (TCA) cycle showed noticeable changes in WT on virus infiltration. The overall higher methylation and demethylation observed in amiRNA transgenics correlated with decreased JLCuGV accumulation. This study demonstrates that amiRNA transgenics showed enhanced resistance to JLCuGV while efficiently maintaining normalcy in their photosynthesis and metabolic pathways as well as homeostasis in the methylation patterns.


Assuntos
Begomovirus/genética , Resistência à Doença/genética , Tabaco/genética , Begomovirus/patogenicidade , Geminiviridae/genética , Geminiviridae/patogenicidade , Jatropha/genética , MicroRNAs/genética , Doenças das Plantas/genética , Doenças das Plantas/virologia , Plantas Geneticamente Modificadas/genética , Interferência de RNA/fisiologia , RNA Viral/genética , Carga Viral
16.
Plant Cell Environ ; 44(6): 1707-1715, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33506956

RESUMO

Geminiviruses are a large group of single-stranded DNA viruses that infect plants and cause severe agricultural losses worldwide. Given geminiviruses only have small genomes that encode a few proteins, viral factors have to interact with host components to establish an environment suitable for virus infection, whilst the host immunity system recognizes and targets these viral components during infection. Post-translational protein modifications, such as phosphorylation, lipidation, ubiquitination, SUMOylation, acetylation and methylation, have been reported to be critical during the interplay between host plants and geminiviruses. Here we summarize the research progress, including phosphorylation and lipidation which usually control the activity and localization of viral factors; as well as ubiquitination and histone modification which are predominantly interfered with by viral components. We also discuss the dynamic competition on protein modifications between host defence and geminivirus efficient infection, as well as potential applications of protein modifications in geminivirus resistance. The summary and perspective of this topic will improve our understanding on the mechanism of geminivirus-plant interaction and contribute to further protection of plants from virus infection.


Assuntos
Geminiviridae/patogenicidade , Interações Hospedeiro-Patógeno/fisiologia , Doenças das Plantas/virologia , Proteínas de Plantas/metabolismo , Plantas/virologia , Membrana Celular/metabolismo , Membrana Celular/virologia , Histonas/metabolismo , Fosforilação , Plantas/metabolismo , Processamento de Proteína Pós-Traducional , Estabilidade Proteica , Ubiquitina/metabolismo
17.
Arch Virol ; 166(1): 299-302, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33068191

RESUMO

Begomoviruses (family Geminiviridae) cause severe diseases in many economically important crops and non-cultivated plants in the warmer regions of the world. Non-cultivated weeds have been reported to act as natural virus reservoirs. In January 2016, Sida plants with yellow mosaic symptoms were found at the edge of an agricultural field in Gujarat, India. Sequence analysis of the viral genomic components cloned from a diseased Sida plant indicated the presence of a distinct monopartite begomovirus (proposed as sida yellow mosaic Gujarat virus) along with a betasatellite (ludwigia leaf distortion betasatellite) and an alphasatellite (malvastrum yellow mosaic alphasatellite). Our results emphasize that this weed may harbor a begomovirus-alphasatellite-betasatellite complex. This host serves as a potential source of virus inoculum, which can be transmitted by whiteflies to other cultivated crops.


Assuntos
Begomovirus/genética , Vírus Satélites/genética , Sida (Planta)/virologia , Animais , DNA Viral/genética , Geminiviridae/genética , Genoma Viral/genética , Hemípteros/virologia , Índia , Filogenia , Doenças das Plantas/virologia , Plantas Daninhas/virologia , Análise de Sequência de DNA/métodos
18.
Annu Rev Entomol ; 66: 389-405, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-32931313

RESUMO

Of the approximately 1,200 plant virus species that have been described to date, nearly one-third are single-stranded DNA (ssDNA) viruses, and all are transmitted by insect vectors. However, most studies of vector transmission of plant viruses have focused on RNA viruses. All known plant ssDNA viruses belong to two economically important families, Geminiviridae and Nanoviridae, and in recent years, there have been increased efforts to understand whether they have evolved similar relationships with their respective insect vectors. This review describes the current understanding of ssDNA virus-vector interactions, including how these viruses cross insect vector cellular barriers, the responses of vectors to virus circulation, the possible existence of viral replication within insect vectors, and the three-way virus-vector-plant interactions. Despite recent breakthroughs in our understanding of these viruses, many aspects of plant ssDNA virus transmission remain elusive. More effort is needed to identify insect proteins that mediate the transmission of plant ssDNA viruses and to understand the complex virus-insect-plant three-way interactions in the field during natural infection.


Assuntos
DNA de Cadeia Simples , Geminiviridae , Insetos Vetores , Insetos , Nanoviridae , Animais , Plantas/virologia
19.
Plant Dis ; 105(4): 1006-1012, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33026306

RESUMO

Virus-like symptoms, including leaf deformation and curling, were observed on nightshade (Solanum nigrum) in Zhejiang Province, China. To identify possible pathogenic viruses or viroids, a symptomatic sample was subjected to deep sequencing of small interfering RNAs. Assembly of the resulting sequences led to identification of a novel geminivirus, provisionally designated nightshade curly top virus (NCTV). The complete genomic DNA sequence is 2,867 nucleotides and encodes seven open reading frames. NCTV shares 77.1% overall nucleotide sequence identity, 86.3% coat protein amino acid identity, and 78.9% replication-associated protein amino acid sequence identity with Tomato pseudo-curly top virus, a member of the genus Topocuvirus. PCR screening of nightshade field isolates indicated that NCTV is widely distributed in Zhejiang. Agrobacterium-mediated inoculation revealed that NCTV is highly infectious to Nicotiana benthamiana, S. nigrum, S. lycopersicum, and S. tuberosum. Based on pairwise comparisons and phylogenetic analyses, NCTV is proposed as a provisional member of the genus Topocuvirus.


Assuntos
Geminiviridae , Solanum nigrum , Solanum , China , Geminiviridae/genética , Genoma Viral/genética , Filogenia , Doenças das Plantas
20.
Food Chem ; 342: 128312, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33268164

RESUMO

The grapevine red blotch disease (GRBD) was first noticed in 2008, impacting grape ripening. In general, GRBD reduces grape and wine quality resulting in significant economic losses. The purpose of the present study was to evaluate the effect of GRBD on agronomical parameters of 'Cabernet Sauvignon' vines at harvest. Using a metabolomics approach, the influence on primary and secondary metabolite profiling in skin + pulp/flesh and seeds were also determined. GRBD influenced °Brix and berry weight, as well as primary and secondary metabolites in both tissues. 1D 1H NMR was effective in quantifying the main primary and secondary metabolites affected by GRBD. RP-HPLC was similarly able to quantify the main phenolics affected. Multivariate analysis showed the influence of the virus on grape metabolites using both tools in two berry tissues. The effectiveness of both tools to describe sample variability was compared and the most affected metabolites in each tissue could be identified.


Assuntos
Geminiviridae/patogenicidade , Doenças das Plantas/microbiologia , Vitis/metabolismo , Vitis/microbiologia , Vinho , Aminoácidos/metabolismo , Cromatografia Líquida de Alta Pressão , Cor , Fenóis/análise , Espectroscopia de Prótons por Ressonância Magnética
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