RESUMO
BACKGROUND: Tobacco mosaic virus (TMV) is a highly infectious plant virus that affects a wide variety of plants and reduces crop yields around the world. Here, we assessed the effectiveness of using Ammi visnaga aqueous seed extract to synthesize silver nanoparticles (Ag-NPs) and their potential to combat TMV. Different techniques were used to characterize Ag-NPs, such as scanning and transmission electron microscopy (SEM, TEM), energy-dispersive X-ray spectroscopy (EDS), fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). RESULTS: TEM demonstrated that the synthesized Ag-NPs had a spherical form with an average size of 23-30 nm and a zeta potential value of -15.9 mV, while FTIR revealed various functional groups involved in Ag-NP stability and capping. Interestingly, the Pre-treatment of tobacco plants (protective treatment) with Ag-NPs at 100-500 µg/mL significantly suppressed viral symptoms, while the Post-treatment (curative treatment) delayed their appearance. Furthermore, protective and curative treatments significantly increased chlorophyll a and b, total flavonoids, total soluble carbohydrates, and antioxidant enzymes activity (PPO, POX and CAT). Simultaneously, the application of Ag-NPs resulted in a decrease in levels of oxidative stress markers (H2O2 and MDA). The RT-qPCR results and volcano plot analysis showed that the Ag-NPs treatments trigger and regulate the transcription of ten defense-related genes (SbWRKY-1, SbWRKY-2, JERF-3, GST-1, POD, PR-1, PR-2, PR-12, PAL-1, and HQT-1). The heatmap revealed that GST-1, the primary gene involved in anthocyanidin production, was consistently the most expressed gene across all treatments throughout the study. Analysis of the gene co-expression network revealed that SbWRKY-19 was the most central gene among the studied genes, followed by PR-12 and PR-2. CONCLUSIONS: Overall, the reported antiviral properties (protective and/or curative) of biosynthesized Ag-NPs against TMV lead us to recommend using Ag-NPs as a simple, stable, and eco-friendly agent in developing pest management programs against plant viral infections.
Assuntos
Nanopartículas Metálicas , Nicotiana , Doenças das Plantas , Extratos Vegetais , Prata , Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Prata/farmacologia , Doenças das Plantas/virologia , Doenças das Plantas/genética , Extratos Vegetais/farmacologia , Nicotiana/genética , Nicotiana/virologia , Resistência à Doença/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Strigolactones (SLs) are plant hormones that regulate diverse developmental processes and environmental responses in plants. It has been discovered that SLs play an important role in regulating plant immune resistance to pathogens but there are currently no reports on their role in the interaction between Nicotiana benthamiana and the tobacco mosaic virus (TMV). In this study, the exogenous application of SLs weakened the resistance of N. benthamiana to TMV, promoting TMV infection, whereas the exogenous application of Tis108, a SL inhibitor, resulted in the opposite effect. Virus-induced gene silencing (VIGS) inhibition of two key SL synthesis enzyme genes, NtCCD7 and NtCCD8, enhanced the resistance of N. benthamiana to TMV. Additionally, we conducted a screening of N. benthamiana related to TMV infection. TMV-infected plants treated with SLs were compared to the control by using RNA-seq. The KEGG enrichment analysis and weighted gene co-expression network analysis (WGCNA) of differentially expressed genes (DEGs) suggested that plant hormone signaling transduction may play a significant role in the SL-TMV-N. benthamiana interactions. This study reveals new functions of SLs in regulating plant immunity and provides a reference for controlling TMV diseases in production.
Assuntos
Resistência à Doença , Regulação da Expressão Gênica de Plantas , Lactonas , Nicotiana , Doenças das Plantas , Vírus do Mosaico do Tabaco , Nicotiana/virologia , Nicotiana/genética , Nicotiana/imunologia , Vírus do Mosaico do Tabaco/fisiologia , Lactonas/farmacologia , Resistência à Doença/genética , Doenças das Plantas/virologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Imunidade Vegetal/genética , Imunidade Vegetal/efeitos dos fármacos , Inativação GênicaRESUMO
Tobacco mosaic virus (TMV), as one of the most traditional and extensive biological stresses, poses a serious threat to plant growth and development. In this work, a series of 1-phenyl/tertbutyl-5-amino-4-pyrazole oxadiazole and arylhydrazone derivatives was synthesized. Bioassay evaluation demonstrated that the title compounds (P1-P18) without a "thioether bond" lost their anti-TMV activity, while some of the ring-opening arylhydrazone compounds exhibited superior in vivo activity against TMV in tobacco. The EC50 value of title compound T8 for curative activity was 139 µg/mL, similar to that of ningnanmycin (NNM) (EC50 = 152 µg/mL). Safety analysis revealed that compound T8 had no adverse effects on plant growth or seed germination at a concentration of 250 µg/mL. Morphological observation revealed that compound T8 could restore the leaf tissue of a TMV-stressed host and the leaf stomatal aperture to normal. A mechanism study further revealed that compound T8 not only restored the photosynthetic and growth ability of the damaged host to normal levels but also enhanced catalase (CAT) activity and reduced the content of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the damaged host, thereby reducing the oxidation damage to the host. TMV-green fluorescent protein (GFP) experiments further demonstrated that compound T8 not only slowed the transmission speed of TMV in the host but also inhibited its reproduction. All of the experimental results demonstrated that compound T8 could reduce the oxidative damage caused by TMV stress and regulate the photosynthetic ability of the host, achieving the ability to repair damage, to make the plant grow normally.
Assuntos
Antivirais , Hidrazonas , Nicotiana , Oxidiazóis , Doenças das Plantas , Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/efeitos dos fármacos , Vírus do Mosaico do Tabaco/fisiologia , Oxidiazóis/química , Oxidiazóis/farmacologia , Hidrazonas/farmacologia , Hidrazonas/química , Hidrazonas/síntese química , Nicotiana/virologia , Nicotiana/efeitos dos fármacos , Doenças das Plantas/virologia , Antivirais/farmacologia , Antivirais/síntese química , Antivirais/química , Desenho de Fármacos , Relação Estrutura-Atividade , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Estrutura MolecularRESUMO
The CDC48 protein, highly conserved in the living kingdom, is a player of the ubiquitin proteasome system and contributes to various cellular processes. In plants, CDC48 is involved in cell division, plant growth and, as recently highlighted in several reports, in plant immunity. In the present study, to further extend our knowledge about CDC48 functions in plants, we analysed the incidence of its overexpression on tobacco development and immune responses. CDC48 overexpression disrupted plant development and morphology, induced changes in plastoglobule appearance and exacerbated ROS production. In addition, levels of salicylic acid (SA) and glycosylated SA were higher in transgenic plants, both in the basal state and in response to cryptogein, a protein produced by the oomycete Phytophthora cryptogea triggering defence responses. The expression of defence genes, notably those coding for some pathogenesis-related (PR) proteins, was also exacerbated in the basal state in transgenic plant lines. Finally, tobacco plants overexpressing CDC48 did not develop necrosis in response to tobacco mosaic virus (TMV) infection, suggesting a role for CDC48 in virus resistance.
Assuntos
Nicotiana , Imunidade Vegetal , Proteínas de Plantas , Plantas Geneticamente Modificadas , Nicotiana/genética , Nicotiana/virologia , Nicotiana/imunologia , Nicotiana/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteína com Valosina/metabolismo , Proteína com Valosina/genética , Doenças das Plantas/virologia , Doenças das Plantas/imunologia , Ácido Salicílico/metabolismo , Regulação da Expressão Gênica de Plantas , Espécies Reativas de Oxigênio/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Vírus do Mosaico do Tabaco/fisiologia , Phytophthora/fisiologia , Phytophthora/patogenicidadeRESUMO
Uncovering the function of phytopathogen effectors is crucial for understanding mechanisms of pathogen pathogenicity and for improving our ability to protect plants from diseases. An increasing number of effectors have been predicted in various plant pathogens. Functional characterization of these effectors has become a major focus in the study of plant-pathogen interactions. In this study, we designed a novel screening system that combines the TMV (tobacco mosaic virus)-GFP vector and Agrobacterium-mediated transient expression in the model plant Nicotiana benthamiana. This system enables the rapid identification of effectors that interfere with plant immunity. The biological function of these effectors can be easily evaluated by observing the GFP fluorescence signal using a UV lamp within just a few days. To evaluate the TMV-GFP system, we initially tested it with well-described virulence and avirulence type III effectors from the bacterial pathogen Ralstonia solanacearum. After proving the accuracy and efficiency of the TMV-GFP system, we successfully screened a novel virulence effector, RipS1, using this approach. Furthermore, using the TMV-GFP system, we reproduced consistent results with previously known cytoplasmic effectors from a diverse array of pathogens. Additionally, we demonstrated the effectiveness of the TMV-GFP system in identifying apoplastic effectors. The easy operation, time-saving nature, broad effectiveness, and low technical requirements of the TMV-GFP system make it a promising approach for high-throughput screening of effectors with immune interference activity from various pathogens.
Assuntos
Vetores Genéticos , Proteínas de Fluorescência Verde , Ensaios de Triagem em Larga Escala , Nicotiana , Doenças das Plantas , Ralstonia solanacearum , Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Vírus do Mosaico do Tabaco/genética , Vírus do Mosaico do Tabaco/patogenicidade , Nicotiana/microbiologia , Nicotiana/genética , Nicotiana/virologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Ralstonia solanacearum/patogenicidade , Ralstonia solanacearum/genética , Ralstonia solanacearum/fisiologia , Ensaios de Triagem em Larga Escala/métodos , Doenças das Plantas/microbiologia , Vetores Genéticos/genética , Virulência , Agrobacterium/genética , Imunidade Vegetal/genética , Interações Hospedeiro-Patógeno/genéticaRESUMO
Our earlier research showed that an interspecific tobacco hybrid (Nicotiana edwardsonii 'Columbia' [NEC]) displays elevated levels of salicylic acid (SA) and enhanced resistance to localized necrotic symptoms (hypersensitive response [HR]) caused by tobacco mosaic virus (TMV) and tobacco necrosis virus (TNV), as compared with another interspecific hybrid (Nicotiana edwardsonii [NE]) derived from the same parents. In the present study, we investigated whether symptomatic resistance in NEC is indeed associated with the inhibition of TMV and TNV and whether SA plays a role in this process. We demonstrated that enhanced viral resistance in NEC is manifested as both milder local necrotic (HR) symptoms and reduced levels of TMV and TNV. The presence of an adequate amount of SA contributes to the enhanced defense response of NEC to TMV and TNV, as the absence of SA resulted in seriously impaired viral resistance. Elevated levels of subcellular tripeptide glutathione (GSH) in NEC plants in response to viral infection suggest that in addition to SA, GSH may also contribute to the elevated viral resistance of NEC. Furthermore, we found that NEC displays an enhanced resistance not only to viral pathogens but also to bacterial infections and abiotic oxidative stress induced by paraquat treatments. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Assuntos
Ácido Salicílico , Vírus do Mosaico do Tabaco , Ácido Salicílico/farmacologia , Nicotiana , Proteínas de Plantas , Plantas , Vírus do Mosaico do Tabaco/fisiologia , Glutationa , Bactérias , Estresse Fisiológico , Doenças das PlantasRESUMO
Dicer-like (DCL) proteins are principal components of RNA silencing, a major defense mechanism against plant virus infections. However, their functions in suppressing virus-induced disease phenotypes remain largely unknown. Here, we identified a role for tomato (Solanum lycopersicum) DCL2b in regulating the wiry leaf phenotype during defense against tobacco mosaic virus (TMV). Knocking out SlyDCL2b promoted TMV accumulation in the leaf primordium, resulting in a wiry phenotype in distal leaves. Biochemical and bioinformatics analyses showed that 22-nt virus-derived small interfering RNAs (vsiRNAs) accumulated less abundantly in slydcl2b mutants than in wild-type plants, suggesting that SlyDCL2b-dependent 22-nt vsiRNAs are required to exclude virus from leaf primordia. Moreover, the wiry leaf phenotype was accompanied by upregulation of Auxin Response Factors (ARFs), resulting from a reduction in trans-acting siRNAs targeting ARFs (tasiARFs) in TMV-infected slydcl2b mutants. Loss of tasiARF production in the slydcl2b mutant was in turn caused by inhibition of miRNA390b function. Importantly, silencing SlyARF3 and SlyARF4 largely restored the wiry phenotype in TMV-infected slydcl2b mutants. Our work exemplifies the complex relationship between RNA viruses and the endogenous RNA silencing machinery, whereby SlyDCL2b protects the normal development of newly emerging organs by excluding virus from these regions and thus maintaining developmental silencing.
Assuntos
Vírus de Plantas , Solanum lycopersicum , Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Solanum lycopersicum/genética , Vírus de Plantas/genética , RNA Interferente Pequeno/genética , Ácidos Indolacéticos , Folhas de Planta/genética , Fenótipo , Doenças das PlantasRESUMO
The essential oil of Cinnamomum camphora is the most widely consumed and used spice in the world today. It has therapeutic effects in medicine and has been shown to have good antibacterial and bacteriostatic effects in agriculture. This study found that C. camphora oil significantly induced plant disease resistance activity. Linalool, its main active component, significantly induced plant disease resistance activity (67.49% at a concentration of 800 µg/ml) over the same concentration of the chitosan oligosaccharide positive control but had no direct effect on tobacco mosaic virus (TMV). In this study of its antiviral mechanism, linalool induced hypersensitive reaction (HR); the overexpression of related defense enzymes SOD, CAT, POD, and PAL; and the accumulation of H2O2 and SA content in N. glutinosa. Besides, linalool induced crops resistance against Colletotrichum lagenarium, Botrytis cinerea, Sclerotinia sclerotiorum, and Phytophthora capsica. Taken together, the anti-TMV mechanism of linalool involved the induction of plant disease resistance through activation of a plant immune response mediated by salicylic acid. Linalool-induced plant disease resistance activity has a long duration, broad spectrum, and rich resources; linalool thus has the potential to be developed as a new plant-derived antiviral agent and plant immune activator.
Assuntos
Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Nicotiana , Resistência à Doença/genética , Peróxido de Hidrogênio , PlantasRESUMO
We have investigated whether the presence of the origin of assembly sequence (OAS) of tobacco mosaic virus (TMV) is necessary for the specific encapsidation of replicating viral RNA. To this end TMV coat protein was expressed from replicating RNA constructs with or without the OAS in planta. In both cases the replicating RNA was specifically encapsidated to give nucleoprotein nanorods, though the yield in the absence of the OAS was reduced to about 60% of that in its presence. Moreover, the nanorods generated in the absence of the OAS were more heterogeneous in length and contained frequent structural discontinuities. These results strongly suggest that the function of the OAS is to provide a unique site for the initiation of viral assembly, leading to a one-start helix, rather than the selection of virus RNA for packaging.
Assuntos
RNA Viral , Vírus do Mosaico do Tabaco , Montagem de Vírus , RNA Viral/metabolismo , Nicotiana/virologia , Vírus do Mosaico do Tabaco/genética , Vírus do Mosaico do Tabaco/fisiologia , Montagem de Vírus/genética , Replicação do RNA , Sequência de Bases , NanotubosRESUMO
Calcium is an important plant immune signal that is essential for activating host resistance, but how RNA viruses manipulate calcium signals to promote their infections remains largely unknown. Here, we demonstrated that tobacco mosaic virus (TMV) coat protein (CP)-interacting protein L (IP-L) associates with calmodulin-like protein 30 (NbCML30) in the cytoplasm and nucleus, and can suppress its expression at the nucleic acid and protein levels. NbCML30, which lacks the EF-hand conserved domain and cannot bind to Ca2+ , was located in the cytoplasm and nucleus and was downregulated by TMV infection. NbCML30 silencing promoted TMV infection, while its overexpression inhibited TMV infection by activating Ca2+ -dependent oxidative stress in plants. NbCML30-mediated resistance to TMV mainly depends on IP-L regulation as the facilitation of TMV infection by silencing NbCML30 was canceled by co-silencing NbCML30 and IP-L. Overall, these findings indicate that in the absence of any reported silencing suppressor activity, TMV CP manipulates IP-L to inhibit NbCML30, influencing its Ca2+ -dependent role in the oxidative stress response. These results lay a theoretical foundation that will enable us to engineer tobacco (Nicotiana spp.) with improved TMV resistance in the future.
Assuntos
Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Calmodulina/genética , Calmodulina/metabolismo , Cálcio/metabolismo , Nicotiana/metabolismo , Doenças das Plantas/genéticaRESUMO
Remorin (REM) is a plant-specific plasma membrane-associated protein regulating plasmodesmata plasticity and restricting viral cell-to-cell movement. Here, we show that palmitoylation is broadly present in group 1 remorin proteins in Nicotiana benthamiana and is crucial for plasma membrane localization and accumulation. By screening the four members of N. benthamiana group 1 remorin proteins, we found that only NbREM1.5 could significantly hamper tobacco mosaic virus (TMV) cell-to-cell movement. We further showed that NbREM1.5 interacts with the movement protein of TMV in vivo and interferes with its function of expanding the plasmodesmata size exclusion limit. We also demonstrated that palmitoylation is indispensable for NbREM1.5 to hamper plasmodesmata permeability and inhibit TMV cell-to-cell movement.
Assuntos
Vírus do Mosaico do Tabaco , Movimento Celular , Lipoilação , Doenças das Plantas , Proteínas de Plantas , Proteínas do Movimento Viral em Plantas/genética , Proteínas do Movimento Viral em Plantas/metabolismo , Nicotiana/metabolismo , Vírus do Mosaico do Tabaco/fisiologiaRESUMO
BACKGROUND AND AIMS: Plants have evolved complex mechanisms to fight against pathogens. Among these mechanisms, pattern-triggered immunity (PTI) relies on the recognition of conserved microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs, respectively) by membrane-bound receptors. Indeed, PTI restricts virus infection in plants and, in addition, BRI1-associated kinase 1 (BAK1), a central regulator of PTI, plays a role in antiviral resistance. However, the compounds that trigger antiviral defences, along with their molecular mechanisms of action, remain mostly elusive. Herein, we explore the role of a fungal extracellular subtilase named AsES in its capacity to trigger antiviral responses. METHODS: In this study, we obtained AsES by recombinant expression, and evaluated and characterized its capacity to trigger antiviral responses against Tobacco mosaic virus (TMV) by performing time course experiments, analysing gene expression, virus movement and callose deposition. KEY RESULTS: The results of this study provide direct evidence that exogenous treatment with recombinant AsES increases a state of resistance against TMV infection, in both arabidopsis and Nicotiana benthamiana plants. Also, the antiviral PTI response exhibited by AsES in arabidopsis is mediated by the BAK1/SERK3 and BKK1/SERK4 co-receptors. Moreover, AsES requires a fully active salicylic acid (SA) signalling pathway to restrict the TMV movement by inducing callose deposition. Additionally, treatment with PSP1, a biostimulant based on AsES as the active compound, showed an increased resistance against TMV in N. benthamiana and tobacco plants. CONCLUSIONS: AsES is a fungal serine protease which triggers antiviral responses relying on a conserved mechanism by means of the SA signalling pathway and could be exploited as an effective and sustainable biotechnology strategy for viral disease management in plants.
Assuntos
Arabidopsis , Vírus do Mosaico do Tabaco , Viroses , Antivirais/metabolismo , Arabidopsis/genética , Imunidade , Peptídeo Hidrolases/metabolismo , Doenças das Plantas , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacologia , Nicotiana/genética , Vírus do Mosaico do Tabaco/fisiologiaRESUMO
Plant nucleotide-binding, leucine-rich, repeat-containing proteins (NLRs) play important roles in plant immunity. NLR expression and function are tightly regulated by multiple mechanisms. In this study, a conserved serine/arginine-rich protein (SR protein) was identified through the yeast one-hybrid screening of a tobacco cDNA library using DNA fragments from the N gene, an NLR that confers immunity to tobacco mosaic virus (TMV). This SR protein showed an interaction with a 3' genomic regulatory sequence (GRS) and has a potential role in regulating the alternative splicing of N. Thus, it was named SR regulator for N, abbreviated SR4N. Further study showed that SR4N plays a positive role in N-mediated cell death but a negative role in N protein accumulation. SR4N also promotes multiple virus replications in co-expression experiments, and this enhancement may not function through RNA silencing suppression, as it did not enhance 35S-GFP expression in co-infiltration experiments. Bioinformatic and molecular studies revealed that SR4N belongs to the SR2Z subtype of the SR protein family, which was conserved in both dicots and monocots, and its roles in repressing viral immunity and triggering cell death were also conserved. Our study revealed new roles for SR2Z family proteins in plant immunity against viruses.
Assuntos
Vírus do Mosaico do Tabaco , Vírus do Mosaico do Tabaco/fisiologia , Proteínas de Plantas/metabolismo , Serina/metabolismo , Imunidade Vegetal , Morte Celular , Nicotiana , Doenças das PlantasRESUMO
The transcription factor SHE1 was induced by tobacco mosaic virus (TMV) infection in tobacco cv. Samsun NN (SNN) and SHE1 inhibited TMV accumulation when expressed constitutively. To better understand the role of SHE1 in virus infection, transgenic SNN tobacco plants generated to over-express SHE1 (OEx-SHE1) or silence expression of SHE1 (si-SHE1) were infected with TMV. OEx-SHE1 affected the local lesion resistance response to TMV, whereas si-SHE1 did not. However, si-SHE1 allowed a slow systemic infection to occur in SNN tobacco. An inhibitor of virus replication (IVR) was known to reduce the accumulation of TMV in SNN tobacco. Analysis of SHE1 and IVR mRNA levels in OEx-SHE1 plants showed constitutive expression of both mRNAs, whereas both mRNAs were less expressed in si-SHE1 plants, even after TMV infection, indicating that SHE1 and IVR were associated with a common signaling pathway. SHE1 and IVR interacted with each other in four different assay systems. The yeast two-hybrid assay also delimited sequences required for the interaction of these two proteins to the SHE1 central 58-79% region and the IVR C-terminal 50% of the protein sequences. This suggests that SHE is a transcription factor involved in the induction of IVR and that IVR binds to SHE1 to regulate its own synthesis.
Assuntos
Nicotiana , Vírus do Mosaico do Tabaco , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Doenças das Plantas/genética , Vírus do Mosaico do Tabaco/fisiologia , Plantas Geneticamente Modificadas , Replicação ViralRESUMO
Virology was born at the end of the 19th century from the recognition of so-called filterable infectious agents that passed through filters designed to retain bacteria. The study of these agents, in particular the tobacco mosaic virus and bacteriophages, has shown the originality of their structural and physico-chemical properties while stimulating the development of molecular biology. Animal viruses, in addition to their own characterization, have served as probes to explore the molecular functioning of eukaryotic cells, including genome organization, transcriptional regulation and mechanisms of oncogenesis. In the early 1960s, a precise definition of virions and mode of virus replication as well as an internationally recognized classification based on the molecular properties of these agents were published. Understanding the pathophysiology of viral infections over the past decades has led to the identification of many new viruses and the development of standardized procedures for virological diagnosis, specific antiviral chemotherapy and effective vaccinations. Combined with the success of more basic studies, these advances have contributed to the exceptionally positive record of virology over the past hundred year.
Title: Une histoire de la virologie. Abstract: La virologie est née à la fin du XIXe siècle de la reconnaissance d'agents infectieux, dits filtrables, qui franchissaient les filtres destinés à retenir les bactéries. L'étude de ces agents, en particulier celle du virus de la mosaïque du tabac et les bactériophages, a conduit à montrer l'originalité de leurs propriétés structurales et physico-chimiques, tout en stimulant le développement de la biologie moléculaire. Les virus des animaux, en plus de leur caractérisation, ont servi de sondes pour explorer le fonctionnement moléculaire des cellules eucaryotes, notamment l'organisation du génome, la régulation transcriptionnelle et les mécanismes d'oncogenèse. Au début des années 1960, une définition précise des virions et du mode de réplication des virus, ainsi qu'une classification internationalement reconnue fondée sur les propriétés moléculaires de ces agents, ont été publiées. Au cours des dernières décennies, la compréhension de la physiopathologie des infections virales a conduit à identifier de nombreux nouveaux virus et à développer des procédures standardisées de diagnostic virologique, une chimiothérapie antivirale spécifique et des vaccinations efficaces. Associées au succès des études plus fondamentales, ces avancées ont contribué au bilan exceptionnellement positif de la virologie au cours des cent dernières années.
Assuntos
Bacteriófagos , Vírus do Mosaico do Tabaco , Vírus , Animais , História do Século XX , Vírus do Mosaico do Tabaco/fisiologia , Bacteriófagos/genética , Biologia Molecular , Bactérias , VirologiaRESUMO
The most common response of a host to pathogens is arguably the asymptomatic response. However, the genetic and molecular mechanisms responsible for asymptomatic responses to pathogens are poorly understood. Here we report on the genetic cloning of two genes controlling the asymptomatic response to tobacco mosaic virus (TMV) in cultivated tobacco (Nicotiana tabacum). These two genes are homologous to tobamovirus multiplication 2A (TOM2A) from Arabidopsis, which was shown to be critical for the accumulation of TMV. Expression analysis indicates that the TOM2A genes might play fundamental roles in plant development or in responses to stresses. Consistent with this hypothesis, a null allele of the TOM2A ortholog in tomato (Solanum lycopersicum) led to the development of bent branches and a high tolerance to both TMV and tomato mosaic virus (ToMV). However, the TOM2A ortholog in Nicotiana glauca did not account for the asymptomatic response to TMV in N. glauca. We showed that TOM2A family is plant-specific and originated from Chlorophyte, and the biological functions of TOM2A orthologs to promote TMV accumulation are highly conserved in the plant kingdom-in both TMV host and nonhost species. In addition, we showed that the interaction between tobacco TOM1 and TOM2A orthologs in plant species is conserved, suggesting a conserved nature of TOM1-TOM2A module in promoting TMV multiplication in plants. The tradeoff between host development, the resistance of hosts to pathogens, and their influence on gene evolution are discussed. Our results shed light on mechanisms that contribute to asymptomatic responses to viruses in plants and provide approaches for developing TMV/ToMV-resistant crops.
Assuntos
Nicotiana/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Vírus do Mosaico do Tabaco/fisiologia , Arabidopsis/genética , Proteínas de Plantas/metabolismo , Nicotiana/microbiologia , Replicação ViralRESUMO
Plant-based nanotechnology programs using virus-like particles (VLPs) and virus nanoparticles (VNPs) are emerging platforms that are increasingly used for a variety of applications in biotechnology and medicine. Tobacco mosaic virus (TMV) and potato virus X (PVX), by virtue of having high aspect ratios, make ideal platforms for drug delivery. TMV and PVX both possess rod-shaped structures and single-stranded RNA genomes encapsidated by their respective capsid proteins and have shown great promise as drug delivery systems. Cowpea mosaic virus (CPMV) has an icosahedral structure, and thus brings unique benefits as a nanoparticle. The uses of these three plant viruses as either nanostructures or expression vectors for high value pharmaceutical proteins such as vaccines and antibodies are discussed extensively in the following review. In addition, the potential uses of geminiviruses in medical biotechnology are explored. The uses of these expression vectors in plant biotechnology applications are also discussed. Finally, in this review, we project future prospects for plant viruses in the fields of medicine, human health, prophylaxis, and therapy of human diseases.
Assuntos
Biotecnologia/métodos , Saúde Global , Nanotecnologia/métodos , Vírus de Plantas/genética , Vírus de Plantas/fisiologia , Animais , Sistemas CRISPR-Cas , Comovirus/fisiologia , Humanos , Camundongos , Nanopartículas/química , Preparações Farmacêuticas , Vírus de Plantas/classificação , Potexvirus/fisiologia , Vírus do Mosaico do Tabaco/fisiologiaRESUMO
Cell-to-cell movement is an important step for initiation and spreading of virus infection in plants. This process occurs through the intercellular connections, termed plasmodesmata (PD), and is usually mediated by one or more virus-encoded movement proteins (MP) which interact with multiple cellular factors, among them protein kinases that usually have negative effects on MP function and virus movement. In this study, we report physical and functional interaction between MP of Tobacco mosaic virus (TMV), the paradigm of PD-moving proteins, and a receptor-like kinase BAM1 from Arabidopsis and its homolog from Nicotiana benthamiana. The interacting proteins accumulated in the PD regions, colocalizing with a PD marker. Reversed genetics experiments, using BAM1 gain-of-function and loss-of-function plants, indicated that BAM1 is required for efficient spread and accumulation the virus during initial stages of infection of both plant species by TMV. Furthermore, BAM1 was also required for the efficient cell-to-cell movement of TMV MP, suggesting that BAM1 interacts with TMV MP to support early movement of the virus. Interestingly, this role of BAM1 in viral movement did not require its protein kinase activity. Thus, we propose that association of BAM1 with TMV MP at PD facilitates the MP transport through PD, which, in turn, enhances the spread of the viral infection.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/virologia , Nicotiana/virologia , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Vírus do Mosaico do Tabaco/fisiologia , Proteínas Virais/metabolismo , Replicação Viral , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/genética , Nicotiana/metabolismo , Proteínas Virais/genéticaRESUMO
An important aspect of plant-virus interaction is the way viruses dynamically move over long distances and how plant immunity modulates viral systemic movement. Salicylic acid (SA), a well-characterized hormone responsible for immune responses against virus, is activated through different transcription factors including TGA and WRKY. In tobamoviruses, evidence suggests that capsid protein (CP) is required for long-distance movement, although its precise role has not been fully characterized yet. Previously, we showed that the CP of Tobacco Mosaic Virus (TMV)-Cg negatively modulates the SA-mediated defense. In this study, we analyzed the impact of SA-defense mechanism on the long-distance transport of a truncated version of TMV (TMV ∆CP virus) that cannot move to systemic tissues. The study showed that the negative modulation of NPR1 and TGA10 factors allows the long-distance transport of TMV ∆CP virus. Moreover, we observed that the stabilization of DELLA proteins promotes TMV ∆CP systemic movement. We also characterized a group of genes, part of a network modulated by CP, involved in TMV ∆CP long-distance transport. Altogether, our results indicate that CP-mediated downregulation of SA signaling pathway is required for the virus systemic movement, and this role of CP may be linked to its ability to stabilize DELLA proteins.
Assuntos
Proteínas do Capsídeo/metabolismo , Interações Hospedeiro-Patógeno , Nicotiana/virologia , Doenças das Plantas/virologia , Ácido Salicílico/imunologia , Transdução de Sinais , Vírus do Mosaico do Tabaco/fisiologia , Proteínas do Capsídeo/genética , Regulação para Baixo , Movimento , Doenças das Plantas/imunologia , Imunidade Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nicotiana/imunologia , Nicotiana/fisiologia , Vírus do Mosaico do Tabaco/genéticaRESUMO
INTRODUCTION: Tobacco mosaic virus-based nanoparticles (TMV VNPs) were previously shown to promote osteogenic differentiation in vitro. This study aims to investigate whether and how TMV VNPs impact on osteoclastogenesis in vitro and bone injury healing in vivo. METHODS: Raw264.7 cells were cultured in osteoclastogenic medium in culture plates coated with or without TMV and TMV-RGD1 VNPs, followed by TRAP staining, RT-qPCR and WB assessing expression of osteoclastogenic marker genes, and immunofluorescence assessing NF-κB activation. TMV and TMV-RGD1-modified hyaluronic acid hydrogel were used to treat mouse tibial bone injury. Bone injury healing was checked by micro-CT and Masson staining. RESULTS: TMV and TMV-RGD1 VNPs significantly inhibited osteoclast differentiation and downregulated the expression of osteoclastogenic marker genes Ctr, Ctsk, Mmp-9, Rank, and Trap. Moreover, TMV and TMV-RGD1 VNPs inhibited NF-κB p65 phosphorylation and nuclear translocation, as well as activation of mTOR/AKT signaling pathway. TMV and TMV-RGD1-modified HA hydrogel strongly promoted mouse tibial bone injury with increased bone mass compared to plain HA hydrogel. The amount of osteoclasts was significantly reduced in TMV and TMV-RGD1 treated mice. TMV-RGD1 was more effective than TMV in inhibiting osteoclast differentiation and promoting bone injury repair. DISCUSSION: These data demonstrated the great potential of TMV VNPs to be developed into biomaterial for bone injury repair or replacement.