Tobacco Mosaic Virus Research Articles

Green synthesis of Cu2O nanoparticles: characterization and application to control tobacco mosaic virus infection

Green synthesis of Cu2O nanoparticles: characterization and application to control tobacco mosaic virus infection

Evaluation of the Sensitivity of Thirteen (13) Promising Cassava Varieties to Diseases (Viruses-Bacteria) and Pests (Mealybugs-Mites) in Central Côte d’Ivoire

Cassava (<i>Manihot esculenta</i>), a plant with starch-rich roots, plays a crucial role in global food security. For producers, it has become both a subsistence and cash crop. In Côte d’Ivoire, it ranks second among crops after yam. However, cassava is severely affected by bacteria, fungi, viruses, mites, and mealybugs, causing yield losses ranging from 20% to 90%. This study was conducted at the Food Crop Research Station (FCRS) of the National Center for Agronomic Research (NCAR) in Bouake in central Côte d’Ivoire. The plant material consisted of thirteen varieties of cassava of the <i>Manihot esculenta</i> species, from the national cassava collection. It aimed to assess the performance of thirteen promising cassava varieties, originating from the national cassava collection, against these diseases and pests under natural infestation conditions. The results revealed that the Yacé variety showed the highest sensitivity to viruses, with an incidence (I) of 96.25% and a severity index (IGS) of 2.8. In contrast, the Yavo variety was the least sensitive, with an incidence of 11.50% and a severity index of 1.3. All varieties studied demonstrated high sensitivity to bacterial blight and mite attacks, with high incidence rates observed in Bocou1 (71.25%) and Bocou3 (68.75%). However, mealybug infestation was relatively low, ranging from 8.75% (Yavo) to 33.75% (Bocou2). Except for mosaic disease, the severity indices for diseases and pests were similar across all varieties.

A Self-Amplifying Human Papillomavirus 16 Vaccine Candidate Delivered by Tobacco Mosaic Virus-Like Particles.

Virus-like particles (VLPs) are naturally occurring delivery platforms with potential for mRNA vaccines that can be used as an alternative to lipid nanoparticles. Here we describe a self-amplifying mRNA vaccine based on tobacco mosaic virus (TMV) expressing a mutated E7 protein from human papillomavirus 16 (HPV16). E7 is an early gene that plays a central role in viral replication and the oncogenic transformation of host cells, but nononcogenic mutant E7 proteins can suppress this activity. Immunization studies involving the delivery of self-amplifying mutant E7 mRNA packaged with TMV coat proteins confirmed the elicitation of E7-specific IgG antibodies. Additional in vitro splenocyte proliferation and cytokine profiling assays indicated the activation of humoral and cellular immune responses. We conclude that TMV particles are suitable for the delivery of mRNA vaccines and can preserve their integrity and functionality in vitro and in vivo.

Factors Influencing Adoption of the PlantVillage Nuru Application for Cassava Mosaic Disease Diagnosis Among Farmers in Benin

Factors Influencing Adoption of the PlantVillage Nuru Application for Cassava Mosaic Disease Diagnosis Among Farmers in Benin

Enhanced Disease Detection for Apple Leaves with Rotating Feature Extraction

Leaf diseases such as Mosaic disease and Black Rot are among the most common diseases affecting apple leaves, significantly reducing apple yield and quality. Detecting leaf diseases is crucial for the prevention and control of these conditions. In this paper, we propose incorporating rotated bounding boxes into deep learning-based detection, introducing the ProbIoU loss function to better quantify the difference between model predictions and real results in practice. Specifically, we integrated the Plant Village dataset with an on-site dataset of apple leaves from an orchard in Weifang City, Shandong Province, China. Additionally, data augmentation techniques were employed to expand the dataset and address the class imbalance issue. We utilized the EfficientNetV2 architecture with inverted residual structures (FusedMBConv and S-MBConv modules) in the backbone network to build sparse features using a top–down approach, minimizing information loss. The inclusion of the SimAM attention mechanism effectively captures both channel and spatial attention, expanding the receptive field and enhancing feature extraction. Furthermore, we introduced depth-wise separable convolution and the CAFM in the neck network to improve feature fusion capabilities. Finally, experimental results demonstrate that our model outperforms other detection models, achieving 93.3% mAP@0.5, 88.7% Precision, and 89.6% Recall. This approach provides a highly effective solution for the early detection of apple leaf diseases, with the potential to significantly improve disease management in apple orchards.

Rapid visual detection of tobacco mosaic virus using a portable paper-based molecularly imprinted sensor

Rapid visual detection of tobacco mosaic virus using a portable paper-based molecularly imprinted sensor

Screening Surface-Defective Graphene Quantum Dots: Promoting Plant Growth and Combating Phytovirus.

Reduced graphene quantum dots (r-GQD), graphene oxide quantum dots (GOQD), and carboxylated graphene quantum dots (C-GQD) are screened to promote tobacco growth and combat tobacco mosaic virus (TMV). First, a 21-day foliar exposure is employed to explore GQDs' impacts on N. benthamiana. Surface-defective GOQD and C-GQD are screened out to facilitate N. benthamiana uptake through leaf stomata, and to promote seedlings of differently leaf ages to various degrees at different concentrations after different durations of foliar exposure. Specially, compared to the ddH2O treatment, GOQD/C-GQD at 400 mg L-1 increase biomass by 44%/68%, increase chlorophyll content by 43%/54% and up-regulate the expression of growth-related genes NtLRX1, CycB, and NtPIP1 by more than two-fold. Second, different from the transient inhibition shown by r-GQD and the TMV enhancement shown by GOQD, C-GQD can directly inactivate TMV infection by inducing TMV aggregation and attachment outside TMV, significantly decreasing TMV replication and hindering TMV spread over 21-day. Specially, C-GQD decreases the transcript abundance of TMV RdRp and TMV CP to 0.11-fold and 0.29-fold, and down-regulates the host defensive response pathways. This work provides a comparative analysis of GQDs with different surface-functionalizations, highlighting C-GQD as a promising nanotechnology tool for promoting plant growth and inactivating phytovirus.

Monitoring of Viral Infections in Vegetable Crops in Agroecosystems of Ukraine

Information on the abundance and diversity of phytopathogenic viruses in Ukraine is very variable and limited. There is a high importance of a complex study of the species composition and ways of spreading crop viruses, as well as the development of epiphytotic forecasting systems, which will help to limit the ranges of these viruses and save crop yields. Consequently, the aim of our study was to explore the species composition and frequency of mono- and mixed virus infection of vegetable crops in Ukrainian agrocenoses and to identify the possible etiology of its occurrence. Methods. The samples were analyzed for the presence of viral antigens by enzyme-linked immunosorbent assay in sandwich and indirect modifications. For the detection of viral antigens in ELISA, test systems manufactured by Loewe were used. To identify the virus, the material was homogenized and purified, and then registered on a reader. Results. The frequency of vegetable crops damaged by diseases of viral etiology increased by 25–27% compared to the previous years of the study. Serological analysis showed that 59% of the studied samples of the Cucurbitaceae family and 54% of the Solanaceae family were affected by the main viral diseases most common in Ukraine. The seed way of transmission of vegetable viruses in Ukraine was demonstrated as one of the sources of viruses in agrocenoses. The presence of antigens to cucumber mosaic virus (CMV) in 14.3% of the studied seeds, zucchini yellow mosaic virus (ZYMV) – 11.2%, and tomato mosaic virus (ToMV) – 12.6% was shown. This allows us to suggest that sowing those seeds in the future will contribute to the spread of these viruses across Ukraine. Analysis of soil samples showed the presence of antigens of cucumber mosaic virus, tobacco mosaic virus, and potato virus X. The lowest level of antigens to CMV was detected in the soils of Vinnytsia region, to PVX – in the Kyiv and Cherkasy regions, and to TMV – in the Odesa region. Conclusions. Vegetable agrocenoses in Ukraine are more often affected by viruses belonging to the Tobamovirus, Cucumovirus, Potyvirus, and Tospovirus genera of the Bromoviridae, Potyviridae, and Bunyaviridae families. In addition to the increasing areas of viral monoinfection, there is an active spread of mixed infection, or "superinfection", in Ukrainian agrocenosis. Mixed infections are mainly formed during the growth and development of the tested vegetable crops. All of this leads to further significant spread of not only mono- but also mixed virus infection of vegetable crops.

Studies on the Detection of Viruses Infecting Capsicum Species in the Northern Zone of Cross River State, Nigeria

The objective of this study was to determine the occurrence, detection, and geographical spread of viruses that infect pepper (Capsicum spp.) in six towns spanning two local government areas (Yala and Ogoja) in the northern zone of Cross River State. A total of 348 leaf samples from symptomatic and asymptomatic pepper plants were randomly collected from farmer's fields during a survey in 2023–2024. The samples were then preliminary tested using an antigen coated plate enzyme-linked immunosorbent assay (ACP-ELISA) with seven antibodies specific for ToLCV, Cowpea aphid borne mosaic virus (CABMV), Cucumber mosaic virus (CMV), Potato virus X (PVX), Tobacco mosaic virus (TMV), and Pepper veinal mottle virus (PVMV). The findings showed that the viruses that infect pepper in Yala had a high cumulative mean incidence, accounting for 56.9% (198 infected samples). Yache in Yala had the highest virus incidence at 90%, while Bansara in Ogoja had the lowest at 40%. At different rates, ToLCV, CMV, PVY, and PVMV were found in the samples; PVX, TMV, and CABMV were not found. The CMV virus was the most commonly discovered of them. Additionally, mixed infections between the viruses—between ToLCV and PVY in Yache and between CMV and PVMV in Bansara—were found. This is the first report on account of viruses found in pepper in the northern part of Cross River State. The findings show that the viruses that cause the infections are common and might potentially be a threat to the production of pepper in that region.

Recognition of a salivary effector by the TNL protein RCSP promotes effector-triggered immunity and systemic resistance in Nicotiana benthamiana.

Insects secret chemosensory proteins (CSPs) into plant cells as potential effector proteins during feeding. The molecular mechanisms underlying how CSPs activate plant immunity remain largely unknown. We show that CSPs from six distinct insect orders induce dwarfism when overexpressed in Nicotiana benthamiana. Agrobacterium-mediated transient expression of Nilaparvata lugens CSP11 (NlCSP11) triggered cell death and plant dwarfism, both of which were dependent on ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), neuregulin 1 (NRG1) and SENESCENCE-ASSOCIATED GENE 101 (SAG101), indicating the activation of effector-triggered immunity (ETI) in N. benthamiana. Overexpression of NlCSP11 led to stronger systemic resistance against Pseudomonas syringae DC3000 lacking effector HopQ1-1 and tobacco mosaic virus, and induced higher accumulation of salicylic acid (SA) in uninfiltrated leaves compared to another effector XopQ that is recognized by a Toll-interleukin-1 receptor (TIR) domain nucleotide-binding leucine-rich repeat receptor (TNL) called ROQ1 in N. benthamiana. Consistently, NlCSP11-induced dwarfism and systemic resistance, but not cell death, were abolished in N. benthamiana transgenic line expressing the SA-degrading enzyme NahG. Through large-scale virus-induced gene silencing screening, we identified a TNL protein that mediates the recognition of CSPs (RCSP), including aphid effector MP10 that triggers resistance against aphids in N. benthamiana. Co-immunoprecipitation, bimolecular fluorescence complementation and AlphaFold2 prediction unveiled an interaction between NlCSP11 and RCSP. Interestingly, RCSP does not contain the conserved catalytic glutamic acid in the TIR domain, which is required for TNL function. Our findings point to enhanced ETI and systemic resistance by a TNL protein via hyperactivation of the SA pathway. Moreover, RCSP is the first TNL identified to recognize an insect effector.

Immunodiagnostic detection of banana bract mosaic virus (BBrMV) infecting abaca through the recombinant coat protein and its sequence diversity analysis in the Philippines

Abaca is an indigenous fiber crop in the Philippines and is an important source of raw fiber worldwide. Banana bract mosaic virus (BBrMV) causes the abaca bract mosaic disease which results in decreased fiber yield and quality. Out of the 261 abaca samples tested, 175 tested positive via ELISA using raw antiserum against the recombinant BBrMV coat protein (CP). To further validate the antisera produced, a total of 48 samples were screened for BBrMV CP fragment via RT-PCR. Out of the 26 positives for RT-PCR, 22 were cloned and sequenced to validate the RT-PCR amplified fragments. Nucleotide analysis showed a high percentage identity (97–98%) towards BBrMV CP Pacific and Indian isolates while phylogenetic analysis revealed clustering of BBrMV CP Philippine abaca isolates with the Pacific group. The results validate the application of polyclonal antibodies against the recombinant coat protein of BBrMV (rCP) for its serological detection in infected abaca.

An Alarming Eastward Front of Cassava Mosaic Disease in Development in West Africa

Begomoviruses are a major threat to cassava production in Africa. Indeed, during the 1990s, the emergence of a recombinant begomovirus (East African cassava mosaic virus-Uganda, EACMV-Ug) resulted in crop devastation and severe famine in Uganda. In 2023, during a pre-survey of cassava farms at Forécariah, South-West Guinea, 22 samples showing peculiar cassava mosaic disease (CMD) symptoms were collected, and subsequent laboratory analysis confirmed the presence of EACMV-Ug in the samples. Deep analysis of DNA-A and DNA-B of the EACMV-Ug isolates from Guinea indicated that they are similar to those associated with the severe CMD epidemic in Uganda in the 1990s. Therefore, a country-wide survey was conducted throughout Guinea in April 2024 to evaluate the extent of the spread of EACMV-Ug in the country and to collect critical CMD epidemiological data. Findings showed a high whitefly population in Lower Guinea averaging 17 per plant; however, the data suggest a spread of EACMV-Ug via infected cuttings. High CMD incidence was found in Lower Guinea and Forest Guinea, whereas the highest CMD severity was observed in Forest Guinea (2.70 ± 0.06) and the lowest CMD severity was found in Middle Guinea (2.20 ± 0.05). Several cases of double and triple infections involving African cassava mosaic virus, East African cassava mosaic virus, East African cassava mosaic Cameroon virus, and EACMV-Ug were observed. EACMV-Ug was detected throughout Guinea, as well as from samples collected in 2022 in Kambia (Sierra Leone). The 63 accessions cultivated in Guinea that were assessed in this study were found susceptible to at least one of the viruses cited above. This study alerts us to an alarming situation in development in West Africa and provides scientific evidence to guide the rapid response needed to contain and stop the progression of EACMV-Ug in West Africa.

The Forgotten Tobamovirus Genes Encoding the 54 kDa Protein and the 4–6 kDa Proteins

This article reviews the literature concerning the largely forgotten tobamovirus gene products for which no functions have been ascribed. One of these gene products is the 54 kDa protein, representing the RNA-dependent RNA polymerase segment of the 183 kDa protein translated from the I1-subgenomic mRNA, but which has been found only by in vitro translation and not in plants. The other is a collection of small proteins, expressed from alternative reading frames (likely from internal ribosome entry sites) in either or both the movement protein gene or the capsid protein gene. Previously, two small proteins were referred to as the 4–6 kDa proteins, since only single proteins of such size had been characterized from tobacco mosaic virus and tomato mosaic virus genomes. Such putative proteins will be referred to here as P6 proteins, since many new proposed P6 open reading frames could be discerned, from an analysis of 45 of 47 tobamovirus genomes, with a coding capacity of >15 amino acids up to 94 amino acids, whereas other peptides with ≤15 amino acids were not considered here. The distribution of the putative P6 proteins among these tobamoviruses is described, as well as the various classes they fall into, based on their distribution with regard to the organization of other genes in the viral genomes. Models also are presented for possible functions of the 54 kDa protein and the P6 proteins, based on data in the literature.

Begomovirus disease of pumpkin crop in India and its management strategies possibility: a review

Pumpkin is an important commercial crop grown worldwide in tropical and subtropical regions. The whitefly-transmitted Pumpkin yellow vein mosaic disease seriously threatens pumpkin cultivation worldwide. The advent of transgenic technology in the 1980s revolutionized the possibilities for introducing virus resistance into agriculturally important plant species. It offered a powerful tool to enhance crop protection and provided a pathway to potentially unlimited sources of resistance against viral diseases. The ongoing research and development in this field continue to explore and refine conventional and non-conventional approaches for effective virus management in agriculture crops. This review focuses on developing transgenic resistance against begomoviruses and discusses possible management strategies to address these challenges.

RNA silencing is activated by N gene-mediated hypersensitive response and plays a key role in local and systemic virus resistance

AbstractIn plants, recognition between resistance gene (R) and virus induces a local hypersensitive response (HR), which is accompanied by systemic acquired resistance (SAR). The dominant resistance gene N in tobacco confers resistance to tobacco mosaic virus (TMV) at both locally inoculated tissues and systemically infected tissues. However, the mechanisms underlying HR- and SAR-mediated viral inhibition are not fully revealed. In this study, we find that Nicotiana glutinosa RNA-binding protein (NgRBP) is an RNA silencing suppressor which enhances TMV-triggered HR. Stronger HR could result in stronger local and systemic RNA silencing as well as SAR. Enhanced RNA silencing in the systemically infected leaves induced by the NgRBP gene is compromised by transient expression of NahG. These results indicate that RNA silencing is activated by HR and plays a crucial role in local and systemic virus resistance. Our results reveal a crosstalk between N gene-mediated virus resistance and RNA silencing which would deepen our understanding of the established HR and SAR models.

Development of infectious clones of mungbean yellow mosaic India virus (MYMIV, Begomovirus vignaradiataindiaense) infecting mungbean [Vigna radiata (L.) R. Wilczek] and evaluation of a RIL population for MYMIV resistance.

Yellow mosaic disease (YMD) is a major constraint for the low productivity of mungbean, mainly in South Asia. Addressing this issue requires a comprehensive approach, integrating field and challenge inoculation evaluations to identify effective solutions. In this study, an infectious clone of Begomovirus vignaradiataindiaense (MYMIV) was developed to obtain a pure culture of the virus and to confirm resistance in mungbean plants exhibiting resistance under natural field conditions. The infectivity and efficiency of three Agrobacterium tumefaciens strains (EHA105, LBA4404, and GV3101) were evaluated using the susceptible mungbean genotype PS16. Additionally, a recombinant inbred line (RIL) population comprising 175 lines derived from Pusa Baisakhi (MYMIV susceptible) and PMR-1 (MYMIV resistant) cross was developed and assessed for YMD response. Among the tested Agrobacterium tumefaciens strains, EHA105 exhibited the highest infectivity (84.7%), followed by LBA4404 (54.7%) and GV3101 (9.80%). Field resistance was evaluated using the coefficient of infection (CI) and area under disease progress curve (AUDPC), identifying seven RILs with consistent resistant reactions (CI≤9) and low AUDPC (≤190). Upon challenge inoculation, six RILs exhibited resistance, while RIL92 displayed a resistance response, with infection occurring in less than 10% of plants after 24 to 29 days post inoculation (dpi). Despite some plants remaining asymptomatic, MYMIV presence was confirmed through specific PCR amplification of the MYMIV coat protein (AV1) gene. Quantitative PCR revealed a very low relative viral load (0.1-5.1% relative fold change) in asymptomatic RILs and the MYMIV resistant parent (PMR1) compared to the susceptible parent (Pusa Baisakhi). These findings highlight the potential utility of the developed infectious clone and the identified MYMIV-resistant RILs in future mungbean breeding programs aimed at cultivating MYMIV-resistant varieties.

Identification of genes governing YMD resistance in soybean cultivar SL 958.

Yellow mosaic disease (YMD) is the most devastating disease of soybean under north Indian conditions. A recombinant inbred line population derived from SL 958 (R) × AGS 456 (S) was used to map the genes imparting YMD resistance. Genotyping by sequencing (GBS) of 148 individuals and the parents was used to identify polymorphic SNPs in the population. These were used to generate linkage maps and subsequently map the QTL. A QTL, MYMIV 1-1.1, was mapped onto chromosome 6. The QTL was mapped at a genetic distance of 114.31 cM, with likelihood ratio of 81.34 (LOD 17.68), explaining 33.80% of the variation for the trait, with an additive effect of 1.22. MYMIV 1-1.1 was flanked by SNPs Gm06_12614920 explaining 33.80% of variation and Gm06_12887789 explaining 31.04% of the variation. The QTL region spanned for a total of 2.798 Mbp. The QTL was mapped in an approximately 4 cM region. Flanking SNPs can be developed into linked markers for effective marker-assisted selection. Out of the genes in the QTL region, Glyma.06G161700 (Suppressor of Gene Silencing/SGS3) is the strongest contender for the resistance gene. This is the first study documenting GBS-based mapping of YMD resistance in soybean. © 2024 Society of Chemical Industry.

Management of sterility mosaic disease in pigeonpea caused by pigeonpea sterility mosaic virus (PPSMV)

Sterility Mosaic Disease (SMD) caused by Pigeonpea Sterility Mosaic Virus (PSMV) is one of the major threats to pigeonpea productivity in India. The incidence of disease under favorable conditions may reduce the yields by up to 80-90%. The virus is transmitted through the eriophyid mite Aceriacajani. Plant viral diseases are managed either through vector control or by the application of antiviral principles. Therefore the present investigation was carried out to find effective acaricides and plant products for the management of SMD. Among all the treatments tested, seed treatment with imidacloprid 70% WS @ 5 g/kg seed+foliar spraying of fenpyroximate 5 EC @ 0.1% (1 ml/L of water) was found to be the most effective in controlling vector and in turn reduced the incidence of sterility mosaic disease with the lowest mean of 22.1% disease incidence as compared with the control (61%).

Assessment of a Structurally Modified Alternanthera Mosaic Plant Virus as a Delivery System for Sarcoma Cells

The virions of plant viruses and their structurally modified particles (SP) represent valuable platforms for recombinant vaccine epitopes and antitumor agents. The possibility of modifying their surface with biological compounds makes them a tool for developing medical biotechnology applications. Here, we applied a new type of SP derived from virions and virus-like particles (VLP) of Alternanthera mosaic virus (AltMV) and well-studied SP from Tobacco mosaic virus (TMV). We have tested the ability of SP from AltMV (AltMV SPV) and TMV virions also as AltMV VLP to bind to and penetrate Ewing sarcoma cells. The adsorption properties of AltMV SPV and TMV SP are greater than those of the SP from AltMV VLP. Compared to normal cells, AltMV SPV adsorbed more effectively on patient-derived sarcoma cells, whereas TMV SP were more effective on the established sarcoma cells. The AltMV SPV and TMV SP were captured by all sarcoma cell lines. In the established Ewing sarcoma cell line, the effectiveness of AltMV SPV penetration was greater than that of TMV SP. The usage of structurally modified plant virus particles as a platform for drugs and delivery systems has significant potential in the development of anticancer agents.

Genome-wide analysis of tobacco NtTOM1/TOM3 gene family and identification of NtTOM1a/ NtTOM3a response to tobacco mosaic virus

BackgroundTOBAMOVIRUS MULTIPLICATION 1 (TOM1) and its homolog TOBAMOVIRUS MULTIPLICATION 3 (TOM3) play a prominent role in the multiplication of tobacco mosaic virus (TMV) in higher plants. Although homologs of NtTOM1/TOM3 genes have been identified in several plant species, little is known about the characteristics and functions of NtTOM1/TOM3 at the genome-wide level in tobacco (Nicotiana tabacum L.).ResultsIn this study, we performed genome-wide identification and expression pattern analysis of the tobacco NtTOM1/TOM3 gene family. Twelve NtTOM1/TOM3 genes were identified and classified into four groups based on phylogenetic analysis. Sequence and conserved domain analyses showed that all these genes contained a specific DUF1084 domain. Expression pattern analysis showed that NtTOM1a, NtTOM1b, NtTOM1d, NtTOM3a, NtTOM3b, and NtTOM3d were induced by TMV at 1-, 3-, and 9 dpi, whereas the expression of other genes was not responsive to TMV at the early infection stage. TMV virion accumulation showed no obvious difference in either nttom1a or nttom3a mutants compared with the wild type. However, the virus propagation was significantly, but not completely, inhibited in the nttom1atom3a double mutant, indicating that other gene family members may function redundantly, such as NtTOM1b and NtTOM1d. In addition, overexpression of NtTOM1a or NtTOM3a also inhibited the TMV replication to some extent.ConclusionsThe present study performed genome-wide analysis of the NtTOM1/TOM3 gene family in tobacco, and identified NtTOM1a and NtTOM3a as important genes involved in TMV multiplication based on functional analysis. These results provide a theoretical basis for further improving TMV resistance in tobacco.