Search

Chemical pesticide delivery is a fundamental aspect of agriculture. However, the extensive use of pesticides severely endangers the ecosystem because they accumulate on crops, in soil, as well as in drinking and groundwater. New frontiers in nano-engineering have opened the door for precision agriculture. We introduced Tobacco mild green mosaic virus (TMGMV) as a viable delivery platform with a high aspect ratio and favorable soil mobility. In this work, we assess the use of TMGMV as a chemical nanocarrier for agriculturally relevant cargo. While plant viruses are usually portrayed as rigid/solid structures, these are "dynamic materials," and they "breathe" in solution in response to careful adjustment of pH or bathing media [e.g., addition of solvent such as dimethyl sulfoxide (DMSO)]. Through this process, coat proteins (CPs) partially dissociate leading to swelling of the nucleoprotein complexes-allowing for the infusion of active ingredients (AI), such as pesticides [e.g., fluopyram (FLP), clothianidin (CTD), rifampicin (RIF), and ivermectin (IVM)] into the macromolecular structure. We developed a "breathing" method that facilitates inter-coat protein cargo loading, resulting in up to  ~ 1000 AIs per virion. This is of significance since in the agricultural setting, there is a need to develop nanoparticle delivery strategies where the AI is not chemically altered, consequently avoiding the need for regulatory and registration processes of new compounds. This work highlights the potential of TMGMV as a pesticide nanocarrier in precision farming applications; the developed methods likely would be applicable to other protein-based nanoparticle systems.

BACKGROUND: Crops are consistently under siege by a multitude of pathogens. These pathogenic microorganisms, including viruses and bacteria, result in substantial reductions in quality and yield globally by inducing detrimental crop diseases, thus posing a significant challenge to global food security. However, the biological activity sepectrum of commercially available pesticides is limited and the pesticide efficacy is poor, necessitating the urgent development of broad‐spectrum and efficient strategies for crop disease prevention and control. RESULTS: The bioassay results revealed that certain target compounds demonstrated outstanding in vivo antiviral efficacy against cucumber mosaic virus and tobacco mosaic virus. In particular, compound D6 showed remarkable antiviral activity against CMV, significantly higher than that of the control agent ningnanmycin. Mechanism of action studies have shown that compound D6 could enhance the activity of defense enzymes and upregulate the expression of genes related to disease resistance, thereby enhancing the antiviral effects in plants. In addition, these compounds displayed superior inhibitory activity against plant bacterial diseases. For Xoo, compound D10 showed an excellent inhibitory effect that was better than that of the control agent bismerthiazol. Scanning electron microscopy and fluorescence double‐staining experiments revealed that compound D10 effectively inhibited bacterial growth by disrupting the cell membrane. CONCLUSION: A series of trifluoromethyl hydrazone derivatives were designed and synthesized, and it was found that they have control effects on plant viruses and bacterial diseases. In addition, this study revealed the mechanism of action of the active compounds and demonstrated their potential as multifunctional crop protectants. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

[Objective] To clarify the inhibitory effect of a new plant immune activating protein (VDAL) on tobacco mosaic virus (TMV). [Method] The inhibition of plant immune activating protein (VDAL) on TMV and the effect on peroxidase (POD) activity in tobacco plants were determined by spot inhibition and spectrophotometry. [Result] VDAL had a good inactivation effect on TMV in vitro. When the inactivation time was 90 min, the inhibition rate of lesions could reach 80.76%. After three times of spraying, the inhibition rate could rise to 85.04%, and the peroxidase activity increased 1.26 times compared with the control. [Conclusion] VDAL may control TMV disease by inactivating the virus and inducing the defense response of tobacco plants. [ABSTRACT FROM AUTHOR]

A proper system for identifying leaf disease, which is crucial for developing agricultural areas, has been addressed in this research using a neural network approach. This study helps find plant illnesses and their stages whenever they occur. Fungal, bacterial, and viral infections are very harmful to plants. Five major tomato diseases have been classified in this research: bacterial spot, early blight, late blight, leaf mold, tomato mosaic virus, and healthy tomato plant leaves. The study underscores the importance of algorithmic adaptability to attain precision in leaf disease identification and emphasizes the potential for customized strategies in achieving accuracy. The classification is done by extracting color, shape, and texture features from a healthy tomato plant leaf image. The feature extraction method is carried out to proceed with the segmentation phase. Features extracted from segmented pictures are used as inputs to a classification algorithm. These five categories were used to finalize the illness categorization stage. The variety of five kinds of tomato leaf images yielded almost 99% classification accuracy. Furthermore, various research gaps have been identified to achieve a more open approach to detecting tomato diseases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In the inducible chlorosis model tobacco, i-hpHSP90C, the silencing of HSP90C activated both salicylic acid (SA)- and cell death-related gene expression and sporadic cell death, resulting in severe chlorosis. In this model plant, we found a transient SA accumulation to a significantly high level at 8 h after induction of HSP90C silencing and consistent upregulation of CBP60-type transcription factors and some SA biosynthetic genes. Exogenous treatment of the model plant with SA alone did not induce chlorosis. The introgression of a gene encoding SA-degrading enzyme, nahGA430V, into tobacco plants with functional N′ tobamovirus resistance gene partially compromised their resistance to tomato mosaic virus but without a clear reduction in SA levels. Expression of nahGA430V stochastically alleviated chlorosis and, subsequently, sporadic cell death upon induction of HSP90C silencing. We applied tenoxicam, a potent inhibitor of the NPR1-dependent SA signaling pathway in Arabidopsis, and found that it alleviated chlorosis in i-hpHSP90C, which accompanied a reduced expression of a CBP60-type transcription factor. However, the expression of PR1a, a well-characterized SA signal marker, was not suppressed by tenoxicam in the i-hpHSP90 plants with alleviated chlorosis. The findings collectively suggest that the plant immunity-related response, including SA production, could have a role in increasing the severity of chlorosis, although the underlying mechanisms remain to be elucidated. [ABSTRACT FROM AUTHOR]

Summary: The development of plant virus‐based expression systems has expanded rapidly owing to their potential applications in gene functional and disease resistance research, and industrial production of pharmaceutical proteins. However, the low yield of certain proteins, especially high‐molecular‐mass proteins, restricts the production scale. In this study, we observed that the tobacco mosaic virus (TMV)‐mediated expression of a foreign protein was correlated with the amount of the movement protein (MP) and developed a TMV‐derived pAT‐transMP vector system incorporating trans‐complementation expression of MP. The system is capable of efficient expression of exogenous proteins, in particular those with a high molecular mass, and enables simultaneous expression of two target molecules. Furthermore, viral expression of competent CRISPR‐Cas9 protein and construction of CRISPR‐Cas9‐mediated gene‐editing system in a single pAT‐transMP construct was achieved. The results demonstrated a novel role for TMV‐MP in enhancing the accumulation of a foreign protein produced from the viral vector or a binary expression system. Further investigation of the mechanism underlying this role will be beneficial for optimization of plant viral vectors with broad applications. [ABSTRACT FROM AUTHOR]

ABSTRACT 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. [ABSTRACT FROM AUTHOR]

In 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. [ABSTRACT FROM AUTHOR]

Protein elicitors can induce plant systemic resistance to pathogens. The recognition of a potential elicitor activates intracellular signaling events, leading to plant resistance against pathogens. In this study, a novel protein elicitor was isolated from the culture filtrate of Verticillium nonalfalfae and named PeVn1, which can induce cell death in several plant species. The PeVn1 gene was then cloned and expressed in Escherichia coli. The recombinant protein PeVn1 triggers cell death in Nicotiana benthamiana in NbBAK1 and NbSOBIR1 dependent manner. Through bioassay analysis showed that the recombinant PeVn1 induced early defense induction events, such as reactive oxygen species burst, callose deposition and the activation of defense hormone signaling pathways and defense enzyme activities. Moreover, PeVn1 significantly enhanced resistance of Nicotiana benthamiana to Sclerotinia sclerotiorum, Botrytis cinerea and N. benthamiana mosaic virus and tomato to Pseudomonas syringae pv. Tomato DC3000. In conclusion, our study reveals that PeVn1 protein as a microbe-associated molecular pattern can induce plant immune responses, which provides a theoretical basis for the development of novel protein-induced disease resistance agents. [ABSTRACT FROM AUTHOR]

Background: TOBAMOVIRUS 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.). Results: In 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. Conclusions: The 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. [ABSTRACT FROM AUTHOR]

Begomoviruses cause losses in several crops around the world. Whiteflies of the Bemisia tabaci cryptic species MEAM1 and MED are efficient vectors of begomoviruses. MEAM1 has been the predominant species in Brazil since the mid‐1990s. MED was detected in Brazil in 2014, and since then, high insect infestations have been reported, mainly in greenhouse production of solanaceous crops. In this study, we compared the transmission efficiency of the begomoviruses tomato severe rugose virus (ToSRV) and tomato rugose mosaic virus (ToRMV) to tomato (Solanum lycopersicum) and bean golden mosaic virus (BGMV) to common bean (Phaseolus vulgaris) by a population of MEAM1 and four populations of MED. B. tabaci MEAM1 efficiently transmitted ToSRV and ToRMV to tomato and BGMV to common bean. B. tabaci MED populations did not transmit ToSRV and ToRMV to tomato. Only one population of B. tabaci MED transmitted BGMV with an efficiency of 3%. PCR analysis indicated that B. tabaci MED can acquire ToSRV, ToRMV and BGMV after a 24 h acquisition access period. Furthermore, some greenhouse tomato plantings from São Paulo state were surveyed for the presence of viruses and whiteflies, and B. tabaci MED were predominant, whereas begomoviruses were absent. Our results demonstrate that populations of MED from São Paulo state are inefficient vectors of begomoviruses, being able to acquire the virus but not transmit it to plants. Understanding this interaction is important and suggests that the spread of B. tabaci MED could change the epidemiological scenario of begomoviruses in areas where this insect predominates. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

X‐ray scattering has become a major tool in the structural characterization of nanoscale materials. Thanks to the widely available experimental and computational atomic models, coordinate‐based X‐ray scattering simulation has played a crucial role in data interpretation in the past two decades. However, simulation of real‐space pair distance distribution functions (PDDFs) from small‐ and wide‐angle X‐ray scattering, SAXS/WAXS, has been relatively less exploited. This study presents a comparison of PDDF simulation methods, which are applied to molecular structures that range in size from β‐cyclodextrin [1 kDa molecular weight (MW), 66 non‐hydrogen atoms] to the satellite tobacco mosaic virus capsid (1.1 MDa MW, 81960 non‐hydrogen atoms). The results demonstrate the power of interpretation of experimental SAXS/WAXS from the real‐space view, particularly by providing a more intuitive method for understanding of partial structure contributions. Furthermore, the computational efficiency of PDDF simulation algorithms makes them attractive as approaches for the analysis of large nanoscale materials and biological assemblies. The simulation methods demonstrated in this article have been implemented in stand‐alone software, SolX 3.0, which is available to download from https://12idb.xray.aps.anl.gov/solx.html. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum L.), the second most important vegetable crop globally, faces a significant threat from various viral diseases. A newly emerging disease, characterised by distinctive shoestring symptoms on leaves and the development of unripe, small, and hard fruit, poses a serious challenge to tomato cultivation in India. An initial survey in an experimental field revealed more than 50% of the plants displayed symptoms of the shoestring disease, resulting in substantial reductions in fruit yield and quality. Transmission electron microscopy (TEM) and molecular analyses identified an isolate of the tomato mottle mosaic virus (ToMMV) in the affected plants. When the partially purified virus was mechanically inoculated into tomato cv. Pusa Ruby plants, it reproduced the characteristic shoestring symptoms, confirming its causal relationship with the disease. Notably, the present shoestring isolate of ToMMV (ToMMV-Tss) was found to induce similar shoestring symptoms in most of the major commercial tomato varieties when inoculated under controlled experimental conditions in the glasshouse, indicating its aggressive nature. Host range studies demonstrated that the ToMMV-Tss can infect several solanaceous species, while cucurbitaceous hosts remained unaffected. Moreover, the virus was found to be seed-transmissible, with a small percentage of seedlings from infected plants displaying symptoms. These findings underscore the significant impact of ToMMV on tomato production in India and emphasise the need for reliable diagnostic tools and effective management strategies to curb the spread and mitigate the impact of this virus on commercial tomato cultivation. [ABSTRACT FROM AUTHOR]

This article, published in Frontiers in Plant Science, discusses the mechanisms of plant virus cell-to-cell transport. The authors focus on complementation studies involving viral movement proteins (MPs) and movement-deficient plant viruses. They provide examples of complementation studies with different plant viruses and discuss the potential mechanisms behind these complementations. The article emphasizes the importance of viral MPs in facilitating the transport of viral genomes through plasmodesmata, the channels connecting neighboring plant cells. The document also explores the ability of certain proteins to complement the transport of RNA viruses, specifically geminivirus C5 and P3 of the fungal virus. These proteins modify plasmodesmata, leading to actin remodeling and inhibition of callose deposition. The document also covers the specificity of transport through plasmodesmata and the mechanisms by which viral movement proteins provide selective intercellular transport. Additionally, the document provides a list of references for various scientific articles related to virology and plant viruses, which can be valuable for researchers studying plant viruses and their interactions with host plants. [Extracted from the article]

Background: The rapid production of influenza vaccines is crucial to meet increasing pandemic response demands. Here, we developed plant-made vaccines comprising centralized consensus influenza hemagglutinin (HA-con) proteins (H1 and H3 subtypes) conjugated to a modified plant virus, tobacco mosaic virus (TMV) nanoparticle (TMV-HA-con). Methods: We compared immune responses and protective efficacy against historical H1 or H3 influenza A virus infections among TMV-HA-con, HA-con protein combined with AddaVax™ adjuvant, and whole-inactivated virus vaccine (Fluzone®). Results: Immunogenicity studies demonstrated robust IgG, IgM, and IgA responses in the TMV-HA-con and HA-con protein vaccinated groups, with relatively low induction of interferon (IFN)-γ+ T-cell responses across all vaccinated groups. The TMV-HA-con and HA-con protein groups displayed partial protection (100% and 80% survival) with minimal weight loss following challenge with two H1N1 strains. The HA-con protein group exhibited 80% and 100% survival against two H3 strains, whereas the TMV-HA-con groups showed reduced protection (20% survival). The Fluzone® group conferred 20–100% survival against two H1N1 strains and one H3N1 strain, but did not protect against H3N2 infection. Conclusions: Our findings indicate that TMV-HA and HA-con protein vaccines with adjuvant induce protective immune responses against influenza A virus infections. Furthermore, our results underscore the potential of plant-based production using TMV-like nanoparticles for developing influenza A virus candidate vaccines. [ABSTRACT FROM AUTHOR]

Abstract Background TOBAMOVIRUS 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.). Results In 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. Conclusions The 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.

Abstract The present study focused on the impact of infection with the tobacco mosaic virus (TMV). Specifically, changes in phytochemicals and gene activity related to pathogenesis-related and phenylpropanoid pathway genes in tomato plants (Solanum lycopersicum L.) during a period of 2–14 days post-inoculation (dpi). According to TEM investigation and coat protein sequence analysis, the purified TMV Egyptian AM isolate (PP133743) has a rod-shaped structure with a diameter of around 110 nm. The RT-qPCR analysis revealed that PR-1 showed an initial increase after TMV infection, as seen in the time-course analysis. In contrast, PR-2 was consistently elevated throughout the infection, suggesting a stronger reaction to the virus and suppressing PAL expression at 6 to 14 dpi. The expression levels of HQT and CHS transcripts exhibited alternating patterns of up-regulation and down-regulation at different time intervals. The HPLC and GC–MS analysis of control- and TMV-infected tomato extracts revealed that different phenolic, flavonoid, and fatty acid compounds were increased (such as naringenin, rutin, flavone, ferulic acid, and pyrogallol) or significantly decreased (such as salicylic acid and chlorogenic acid) after TMV infection. The ability of TMV to inhibit most polyphenolic compounds could potentially accelerate the viral life cycle. Consequently, focusing on enhancing the levels of such suppressed compounds may be critical for developing plant viral infection management strategies.

Currently transient expression is one of the preferred plant-based technologies for recombinant protein manufacturing, particularly in respect to pharmaceutically relevant products. Modern hybrid transient expression systems combine the features of Agrobacterium tumefaciens and viral vectors. However, host plant reaction to Agrobacterium-mediated delivery of gene of interest can negatively affect foreign protein accumulation. In this study, we investigated whether the modulation of plant immune response through knockdown of the Nb-SABP2 and Nb-COI1 N. benthamiana genes could improve recombinant protein yield. In plants, the SABP2 and COI1 proteins are involved in the salicylic acid and jasmonic acid metabolism, respectively. We exemplified the utility of this approach with the green fluorescence (GFP) and b nerve growth factor (bNGF) proteins: compared to the tobacco mosaic virus (TMV)-based vector the Nb-SABP2 and Nb-COI1-suppressed plants provided an increased recombinant protein accumulation. We also show that this strategy is extendable to the expression systems utilizing potato virus X (PVX) as the vector backbone: the enhanced amounts of bNGF were detected in the Nb-SABP2 and Nb-COI1-depleted leaves co-infiltrated with the PVX-bNGF. These findings suggest that modulating host plant reaction to agrodelivery of expression vectors could be useful for improving transient foreign protein production in N. benthamiana. [ABSTRACT FROM AUTHOR]

SUMMARY: The outcome of certain plant–virus interaction is symptom recovery, which is accompanied with the emergence of asymptomatic tissues in which the virus accumulation decreased dramatically. This phenomenon shows the potential to reveal critical molecular factors for controlling viral disease. MicroRNAs act as master regulators in plant growth, development, and immunity. However, the mechanism by which miRNA participates in regulating symptom recovery remains largely unknown. Here, we reported that miR172 was scavenged in the recovered tissue of tobacco mosaic virus (TMV)‐infected Nicotiana tabacum plants. Overexpression of miR172 promoted TMV infection, whereas silencing of miR172 inhibited TMV infection. Then, TARGET OF EAT3 (TOE3), an APETALA2 transcription factor, was identified as a downstream target of miR172. Overexpression of NtTOE3 significantly improved plant resistance to TMV infection, while knockout of NtTOE3 facilitated virus infection. Furthermore, transcriptome analysis indicated that TOE3 promoted the expression of defense‐related genes, such as KL1 and MLP43. Overexpression of these genes conferred resistance of plant against TMV infection. Importantly, results of dual‐luciferase assay, chromatin immunoprecipitation‐quantitative PCR, and electrophoretic mobility shift assay proved that TOE3 activated the transcription of KL1 and MLP43 by binding their promoters. Moreover, overexpression of rTOE3 (the miR172‐resistant form of TOE3) significantly reduced TMV accumulation compared to the overexpression of TOE3 (the normal form of TOE3) in miR172 overexpressing Nicotiana benthamiana plants. Taken together, our study reveals the pivotal role of miR172/TOE3 module in regulating plant immunity and in the establishment of recovery in virus‐infected tobacco plants, elucidating a regulatory mechanism integrating plant growth, development, and immune response. Significance Statement: miR172/TOE3 module is well‐known for its role in regulating reproductive process. In this study, we demonstrated that miR172/TOE3 module plays an important role in regulating the resistance of tobacco to TMV infection and the formation of symptom recovery. [ABSTRACT FROM AUTHOR]

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 signifi cant spread of not only mono-but also mixed virus infection of vegetable crops. [ABSTRACT FROM AUTHOR]

BACKGROUND: The discovery of antimicrobial ingredients from natural products could be an effective way to create novel fungicides. Rubia cordifolia L., a traditional Chinese herb, may have antimicrobial effects on plant pathogens according to our previous screening study. RESULTS: Rubia cordifolia L. extracts had moderate inhibitory effects on apple Valsa canker (Valsa mali) and tomato grey mould (Botrytis cinerea) at a concentration of 10 mg mL−1. With the use of bioguided isolation methods, eight compounds (1–8) were obtained, including the new compound 2,2,6‐trimethyl‐6‐(4‐methylphenyl)‐tetrahydropyrano‐ 3‐ol (7), and seven quinone derivatives. Two compounds, mollugin (1) and 1,3,6‐trihydroxy‐2‐methylanthraquinone (6), were found to exhibit outstanding antifungal activities against V. mali and Phytophthora capsici Leon. The half maximal effective concentration (EC50) of compound 1 and compound 6 against V. mali were 79.08 and 81.78 μg mL−1, respectively, and the EC50 of compound 6 against P. capsici was 4.86 μg mL−1. Compound 1 also showed excellent activity against tobacco mosaic virus (TMV). The inactive, inductive, protective and curative activities against TMV were 84.29%, 83.38%, 86.81%, and 60.02%, respectively, at a concentration of 500 μg mL−1, which were all close to or greater than that of the positive control (100 μg mL−1 chitosan oligosaccharide, COS). CONCLUSION: Mollugin and 1,3,6‐trihydroxy‐2‐methylanthraquinone are potentially valuable active compounds that lay a foundation for research on botanical fungicide products derived from R. cordifolia L. and provide lead structures for quinone derivative synthesis and structural modification. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study used the DNA of Bacillus amyloliquefaciens Ba168 as a template to amplify the flagellin BP8-2 gene and ligate it into the fusion expression vector pCAMBIA1300-35S-EGFP after digestion for the construction of the expression vector pCAMBIA1300-EGFP-BP8-2. Next, using Nicotiana benthamiana as receptor material, transient expression was carried out under the mediation of Agrobacterium tumefaciens C58C1. Finally, the transient expression and subcellular localisation of flagellin BP8-2 protein were analysed using the imaging of co-transformed GFP under laser confocal microscopy. The results showed that flagellin BP8-2 was localised in the cell membrane and nucleus, and the RT-PCR results showed that the BP8-2 gene could be stably expressed in tobacco leaf cells. Furthermore, there was stronger antiviral activity against tobacco mosaic virus (TMV) infection in Nicotiana glutinosa than in BP8-2 and ningnanmycin, with an inhibitory effect of 75.91%, protective effect of 77.45%, and curative effect of 68.15%. TMV movement and coat protein expression were suppressed, and there was a high expression of PR-1a, PAL, and NPR1 in BP8-2-treated tobacco leaf. These results suggest that flagellin BP8-2 inhibits TMV by inducing resistance. Moreover, BP8-2 has low toxicity and is easily biodegradable and eco-friendly. These results further enrich our understanding of the antiviral mechanisms of proteins and provide alternatives for controlling viral diseases in agriculture. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Perilla essential oil (PEO) is reported as an aromatic yellowish oily substance with a volatile odor extracted from perilla leaves. It exhibits various biological activities except anti-tobacco mosaic virus (TMV) activity. In this study, we investigated the main components and anti-TMV activity of PEO, identified its primary active components, and examined its mode of action. The results indicated that PEO exhibited anti-TMV activity (65.58%) at 800 μg/mL, with perillaldehyde identified as the main active component. The protective, curative, and inactivation activities of perillaldehyde at 800 μg/mL were 80.41%, 73.42%, and 34.93%, respectively. These values were significantly higher than those of the control drug (commercial chitosan oligosaccharide) and the protective and curative activities were superior to those of ningnanmycin. The results of the mode of action showed that perillaldehyde induced a hypersensitive response (HR) in tobacco. Transmission electron microscope (TEM) observation revealed that perillaldehyde had no direct effect on TMV particles. The treatment of Nicotiana glutinosa with perillaldehyde at 800 μg/mL indicated that perillaldehyde had significant induction activity (58.46%). The expression of three pathogenesis-related tobacco genes (PR genes), including nonexpressor of pathogenesis-related genes 1 (NPR1), pathogenesis-related protein 1 gene (PR1), and pathogenesis-related protein 5 gene (PR5), were induced and upregulated by perillaldehyde treatment. Perillaldehyde also induced the overexpression of the phenylalanine ammonia-lyase gene (PAL), respiratory burst oxidase homolog B gene (RBOHB), and protochlorophyllide oxidoreductase gene 1 (POR1). Furthermore, perillaldehyde increased the salicylic acid (SA) and H2O2 contents in tobacco leaves, and enhanced the activities of four defense enzymes: superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and phenylalanine ammonia-lyase (PAL). N. glutinosa was treated with perillaldehyde at 800 μg/mL for 24 h, and the results showed that the highest SA and H2O2 contents (1032.08 pmol/L and 23.40 μmol/g FW, respectively) were obtained in tobacco leaves. Defense enzyme activities also reached a maximum at 800 μg/mL, and the activities of CAT, PAL, POD, and SOD increased by 1.76, 1.95, 2.17, and 3.78 times, respectively, compared to the control. The results of the study showed that perillaldehyde may enhance resistance to pathogen infection by inducing systemic acquired resistance (SAR), which may contribute to the activation of SA signal transduction pathway. Therefore, perillaldehyde has the potential for application in agriculture as a novel antiviral agent and immune inducer. [ABSTRACT FROM AUTHOR]

Loquat leaves exhibiting obvious yellowing, blistering, mosaic, leaf upward cupping, crinkle, and leaf narrowing were identified in Panzhihua City, Sichuan Province, China. High-throughput sequencing (HTS) with the ribo-depleted cDNA library was employed to identify the virome in the loquat samples; only tomato mosaic virus (ToMV) and citrus exocortis viroid (CEVd) were identified in the transcriptome data. The complete genome sequence of ToMV and CEVd were obtained from the loquat leaves. The full-length genome of the ToMV-loquat is 6376 nt and comprises four open reading frames (ORFs) encoding 183 kDa protein, RNA-dependent RNA polymerase (RdRp), movement protein (MP), and coat protein (CP), respectively. A pairwise identity analysis showed that the complete sequence of the ToMV-loquat had a nucleotide identity between 98.5 and 99.3% with other ToMV isolates. A phylogenetic analysis indicated that ToMV-loquat was more closely related to ToMV-IFA9 (GenBank No. ON156781). A CEVd sequence with 361 nt in length was amplified based on the HTS contigs, sequence alignment indicated CEVd-loquat had the highest identity with the strain of CEVd-Balad (GenBank No. PP869624), phylogenetic analysis showed that CEVd-loquat was more closely related to CEVd-lettuce (GenBank No. ON993891). This significant discovery marks the first documentation and characterization of ToMV and CEVd infecting loquat plants, shedding light on potential threats to loquat cultivation and providing insights for disease management strategies. [ABSTRACT FROM AUTHOR]

There has been a growing interest in extracting essential oils from aromatic plants as potential sources of biorational pesticides. In the present study, essential oil emulsions of Satureja bakhtiarica (SEO), Oliveria decumbens (OEO), Trachyspermum ammi (TEO) and Zataria multiflora (ZEO) were prepared. Their major chemical compositions were characterized and their antiviral effects were evaluated against two important plant viruses: Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). SEO and ZEO indicated higher antiviral activity in comparison with OEO and TEO (p < 0.05). In systemic bioassay, the pre-treatment test of ZEO and SEO showed a reduced level of TMV accumulation in TMV-infected tobacco, with rates of 26.75% and 23.97%, respectively. Also, the two essential oils had mechanisms by which plant resistance acted against plant viruses. These mechanisms involved the activities of several defense-related enzymes (PAL and POD) and genes (ICS1, NPR1, and PR-1a). These results indicate that the essential oils of Zataria multiflora and Satureja bakhtiarica have the potential to be used as sources of effective antiviral agents and eco-friendly pesticide. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus (TMV) was the first virus to be studied in detail and, for many years, TMV and other tobamoviruses, particularly tomato mosaic virus (ToMV) and tobamoviruses infecting pepper (Capsicum spp.), were serious crop pathogens. By the end of the twentieth and for the first decade of the twenty-first century, tobamoviruses were under some degree of control due to introgression of resistance genes into commercial tomato and pepper lines. However, tobamoviruses remained important models for molecular biology, biotechnology and bio-nanotechnology. Recently, tobamoviruses have again become serious crop pathogens due to the advent of tomato brown rugose fruit virus, which overcomes tomato resistance against TMV and ToMV, and the slow but apparently inexorable worldwide spread of cucumber green mottle mosaic virus, which threatens all cucurbit crops. This review discusses a range of mainly molecular biology-based approaches for protecting crops against tobamoviruses. These include cross-protection (using mild tobamovirus strains to 'immunize' plants against severe strains), expressing viral gene products in transgenic plants to inhibit the viral infection cycle, inducing RNA silencing against tobamoviruses by expressing virus-derived RNA sequences in planta or by direct application of double-stranded RNA molecules to non-engineered plants, gene editing of host susceptibility factors, and the transfer and optimization of natural resistance genes. [ABSTRACT FROM AUTHOR]

Rupert Jethro Best (1903–91), working alone at the Waite Agricultural Research Institute in Adelaide between 1934 and 1937, was among the first to purify tobacco mosaic virus (TMV) and to propose that it was a complex macromolecule containing protein and another reactive group that was responsible for infectivity of the virus. However, his research was completely overshadowed by that of Wendell Stanley and the duo of Frederick Bawden and Norman (aka Bill) Pirie, working in the United States of America and Great Britain, respectively, to the point where Best is not even mentioned in modern histories of TMV. Many factors have contributed to this lack of recognition for Best. Professor James Prescott, a soil scientist and Best's supervisor at the Waite Institute, failed to appreciate the significance of his research, leading to critical delays in publication that prevented him from claiming precedence for purifying TMV. When Best's research was eventually published, it was in Australian journals that were not broadly distributed, resulting in minimal international exposure for his research. The plant virology community within which he worked in Australia was very small and entirely focused on plant disease control, and not concerned with fundamental questions about the composition of viruses. Communication with similarly interested scientists in the Northern Hemisphere was hindered by the great distances involved. In this paper, pioneering research done by Best on TMV is reviewed, and placed in context with that undertaken by Stanley and by Bawden and Pirie, who are best remembered for purifying TMV and characterising its physicochemical properties. Rupert Jethro Best, working alone in Adelaide at the Waite Agricultural Research Institute, was among the first to purify tobacco mosaic virus and to provide evidence that it was a heterogeneous macromolecule, composed mainly of protein but also small prosthetic groups with the properties of a weak acid, wherein lay the activity of the virus. This paper describes the contributions of Rupert Best to early theories on the material nature and mode of reproduction of viruses. Photographer unknown, State Library of South Australia. [ABSTRACT FROM AUTHOR]

SUMMARY: 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. Significance Statement: The development of a robust high‐throughput functional screening assay for pathogen effectors will facilitate the study in plant‐pathogen interactions. We established a novel screening system using the TMV‐GFP vector, enabling the rapid identification of effectors that interfere with plant immunity by observing GFP fluorescence under a UV lamp within a few days. The TMV‐GFP system is a promising approach for high‐throughput screening of effectors from diverse pathogens. [ABSTRACT FROM AUTHOR]

Triticum mosaic virus (TriMV; genus Poacevirus;family Potyviridae) is an economically important virus in the Great Plains region of lhe United States. TriMV is transmitted by the wheat curl mite (Aceria tosichella) Type 2 genotype but not by Type I. Helper component-proteinase (HC-Pro) is a vector transmission determinant for several potyvirids, but the role of HC-Pro in TriMV transmission is unknown. In this study, we examined the requirement of the HC-Pro cistron of TriMV for wheat curl mite (Type 2) transmission through deletion and point mutations and constructing TriMV chimeras with heterologous HC-Pros from other potyvirids. TriMV with complete deletion of HC-Pro failed to be transmitted by wheat curl mites at detectable levels. Furthermore, TriMV chimeras with heterologous HC- Pros from aphid-transmitted turnip mosaic virus and tobacco etch virus, or wheat curl mite-transmitted wheat streak mosaic virus, failed to be transmitted by wheat curl mites. These data suggest that heterologous HC-Pros did not complement TriMV for wheat curl mite transmission. A decreasing scries of progressive nested in-frame deletions at the N-terminal region of HC-Pro comprising amino acids 3 to 125, 3 to 50, 3 to 25, 3 to 15, 3 to 8, and 3 and 4 abolished TriMV transmission by wheat curl mites. Additionally, mutation of conserved Hisat, Cys_w, orCysjj to Ala in HC-Pro abolished TriMV transmissibility by wheat curl mites. These data suggest that the N-terminal region of HC-Pro is crucial for TriMV transmission by wheat curl mites. Collectively, these data demonstrate that lhe HC-Pro cistron of TriMV is a viral determinant for wheat curl mite transmission. [ABSTRACT FROM AUTHOR]

During surveys conducted in several greenhouses in northwestern and southwestern Iran in the fall of 2021-2022, viral symptoms such as leaf mosaic, leaf deformation, and shoestring were observed in several tomato plants. Reverse transcription polymerase chain reaction (RT-PCR) was performed using specific primers to detect the tomato brown rugose fruit virus (ToBRFV). A 458 base pair fragment corresponding to a part of the coat protein gene was amplified in all symptomatic samples. Sequence blast analysis and multiple alignment of the sequenced isolate with those of the isolates obtained from GenBank revealed 99.76% nucleotide sequence identity with existing GenBank isolates. Phylogenetic analysis grouped ToBRFV isolates into three clades, the Iranian isolate (Jol-F-2022) fell into clade II. The possibility of mixed infection in the samples with important viruses was investigated using universal orthotospovirus primers, pepper mild mottle virus (PMMoV), tomato mosaic virus (ToMV), and cucumber mosaic virus (CMV)-specific primers. In five samples, CMV-specific primers amplified a 657-base pair fragment of the envelope protein gene, whereas no fragment was amplified with general primers for the orthotospovirus genus and specific primers for PMMoV, ToMV. Nucleotide blast (BLASTn) analysis revealed a nucleotide sequence identity around 95.13-98.85 between the Iranian CMV isolate and the corresponding sequences in the GenBank. Phylogenetic analysis based on the nucleotide sequences of the coat protein gene grouped the CMV isolates into three major groups, the Iranian isolate grouped with the Indian CMV isolates in the subgroup IB. Biological studies were performed by mechanical inoculation of an infected sample on Nicotiana rustica. The inoculated plants showed severe mosaic symptoms at 15 days post inoculation (dpi), and infection by both viruses was confirmed through RT-PCR using specific primers. This study presents the first report of mixed infection of tomato plants with ToBRFV and CMV in Iran. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central European Agriculture is the property of Journal of Central European Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The tomato Tm-22 gene was considered to be one of the most durable resistance genes in agriculture, protecting against viruses of the Tobamovirus genus, such as tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV). However, an emerging tobamovirus, tomato brown rugose fruit virus (ToBRFV), has overcome Tm-22 , damaging tomato production worldwide. Tm-22 encodes a nucleotide-binding leucine-rich repeat (NLR) class immune receptor that recognizes its effector, the tobamovirus movement protein (MP). Previously, we found that ToBRFV MP (MPToBRFV ) enabled the virus to overcome Tm-22 -mediated resistance. Yet, it was unknown how Tm-22 remained durable against other tobamoviruses, such as TMV and ToMV, for over 60 years. Here, we show that a conserved cysteine (C68) in the MP of TMV (MPTMV ) plays a dual role in Tm-22 activation and viral movement. Substitution of MPToBRFV amino acid H67 with the corresponding amino acid in MPTMV (C68) activated Tm-22 -mediated resistance. However, replacement of C68 in TMV and ToMV disabled the infectivity of both viruses. Phylogenetic and structural prediction analysis revealed that C68 is conserved among all Solanaceae-infecting tobamoviruses except ToBRFV and localizes to a predicted jelly-roll fold common to various MPs. Cell-to-cell and subcellular movement analysis showed that C68 is required for the movement of TMV by regulating the MP interaction with the endoplasmic reticulum and targeting it to plasmodesmata. The dual role of C68 in viral movement and Tm-22 immune activation could explain how TMV was unable to overcome this resistance for such a long period.

Abstract Tobacco mosaic virus (TMV; genus Tobamovirus) is one of the most prevailing pathogens that seriously affects the quality and yield of tobacco (Nicotiana tabacum) leaves. Cross-protection using mild strains is a potential strategy for the biological prevention of plant viral diseases. Complementary mutations in attenuated strains may cause attenuated ones to suddenly evolve into virulent strains, which limits the application of cross-protection in practice. To data there has been no study on engineering the complementary mutation sites to generate stable attenuated mutants for cross-protection. In this study, we found that the substitution of the conserved arginine at position 88 (R88) in p126 protein with alanine (A) abolished the cell-to-cell movement and reduced the replication of TMV. However, a spontaneous complementary mutation of serine at position 114 (S114) to lysine (K) in p126 restored TMV virulence. Substitution of S114 with R in p126 restored the systemic infection but not the virulence of TMV, therefore, the mutant TMV-R88A/S114R was an attenuated one. Furthermore, our results showed that TMV-R88A/S114R was a stable attenuated mutant, and could effectively protect tobacco plants against the wild-type TMV infection. This study reports a promising TMV mild mutant for cross-protection in tobacco plants by modifying the complementary mutation site in p126.

Tobacco mosaic virus (TMV) is widely recognized as one of the most important plant viruses, causing significant agricultural losses in terms of both quality and yield worldwide each year. This study demonstrated the biosynthesis of copper oxide nanoparticles (CuONPs) using orange peel extract for effective control of TMV infection both in vitro and in vivo. After treatment with CuONPs (100 mg/L) for 2 h, TMV particles exhibited evident fragmentation in vitro, reducing infectivity on tobacco plants. Similarly, the application of CuONPs on Nicotiana benthamiana (N. benthamiana) positively impeded viral replication and accumulation in vivo. Interestingly, the expression of systemic resistance-related genes (PR1, PR2, ERF1, and JAZ3) in the host plant was up-regulated by CuONPs treatment, supporting that CuONPs activated plant immunity to inhibit TMV. Importantly, the application of CuONPs (100 mg/L) did not exhibit any toxic effects on tobacco and, instead, resulted in the promotion of chlorophyll content, as well as an increase in the fresh weight and dry weight of the plant when compared to the control treatment. Overall, we proposed that the appropriate concentration of CuONPs (100 mg/L) can directly break viral particles by passivating, boost plant immunity by stimulating systemic acquired resistance (SAR), and provide nutritional supplements to promote plant growth. [ABSTRACT FROM AUTHOR]

Plant viruses cause substantial losses in crop yield and quality; therefore, devising new, robust strategies to counter viral infections has important implications for agriculture. Virus inhibitory protein endoplasmic reticulum-associated interferoninducible (Viperin) proteins are conserved antiviral proteins. Here, we identified a set of Viperin and Viperin-like proteins from multiple species and tested whether they could interfere with RNA viruses in planta. Our data from transient and stable overexpression of these proteins in Nicotiana benthamiana reveal varying levels of interference against the RNA viruses tobacco mosaic virus (TMV), turnip mosaic virus (TuMV), and potato virus x (PVX). Harnessing the potential of these proteins represents a novel avenue in plant antiviral approaches, offering a broader and more effective spectrum for application in plant biotechnology and agriculture. Identifying these proteins opens new avenues for engineering a broad range of resistance to protect crop plants against viral pathogens. [ABSTRACT FROM AUTHOR]

Tomato mosaic virus (ToMV), an economically important virus that affects a wide range of crops, is highly contagious, and its transmission is mediated by mechanical means, and through contaminated seeds or planting materials, making its management challenging. To contain its wide distribution, early and accurate detection of infection is required. A survey was conducted between January and May, 2023 in major tomato growing counties in Kenya, namely, Baringo, Kajiado, Kirinyaga and Laikipia, to establish ToMV disease incidence and to collect samples for optimization of the reverse transcription loop-mediated isothermal amplification assay (RT-LAMP) assay. A RT-LAMP assay, utilizing primers targeting the coat protein, was developed and evaluated for its performance. The method was able to detect ToMV in tomato samples within 4:45 minutes, had a 1,000-fold higher sensitivity than conventional reverse transcription polymerase chain reaction (RT-PCR) method and was specific to ToMV. Furthermore, the practical applicability of the assay was assessed using tomato samples and other solanaecous plants. The assay was able to detect the virus in 14 tomato leaf samples collected from the field, compared to 11 samples detected by RT-PCR, further supporting the greater sensitivity of the assay. To make the assay more amenable for on-site ToMV detection, a quick-extraction method based on alkaline polyethylene glycol buffer was evaluated, which permitted the direct detection of the target virus from crude leaf extracts. Due to its high sensitivity, specificity and rapidity, the RT-LAMP method could be valuable for field surveys and quarantine inspections towards a robust management of ToMV infections. [ABSTRACT FROM AUTHOR]

Simple Summary: Natural microorganism-derived products are an essential source of valuable pharmaceuticals and agrichemicals. Streptomyces spp. are the most environmentally abundant bacteria that are capable of producing various valuable natural products exhibiting significant biological activity to be used in such industries as medicine, environmental science, food industry, and agriculture. However, many natural products among Streptomyces bacteria remain unstudied. Because of the rapid increase in antimicrobial and pesticide resistance, it is currently extremely topical to develop novel antibiotics, antiviral agents, agrichemicals, and other substances. The modern methods of molecular biology allow one to detect antimicrobial resistance gene clusters in the bacterial cell. Our study detected antibiotics and terpenes in cells of investigated bacteria; these compounds are of significant interest for the plant-growing sector. This work aimed to study the genome organization and the metabolic potential of Streptomyces carpaticus strain SCPM-O-B-9993, a promising plant-protecting and plant-stimulating strain isolated from brown semi-desert soils with very high salinity. The strain genome contains a linear chromosome 5,968,715 bp long and has no plasmids. The genome contains 5331 coding sequences among which 2139 (40.1%) are functionally annotated. Biosynthetic gene clusters (BGCs) of secondary metabolites exhibiting antimicrobial properties (ohmyungsamycin, pellasoren, naringenin, and ansamycin) were identified in the genome. The most efficient period of SCPM-O-B-9993 strain cultivation was 72 h: during this period, the culture went from the exponential to the stationary growth phase as well as exhibited excellent phytostimulatory properties and antiviral activity against the cucumber mosaic virus in tomatoes under laboratory conditions. The Streptomyces carpaticus SCPM-OB-9993 strain is a biotechnologically promising producer of secondary metabolites exhibiting antiviral and phytostimulatory properties. [ABSTRACT FROM AUTHOR]

Viral diseases pose a significant threat to tomato crops (Solanum lycopersicum L.), one of the world's most economically important vegetable crops. The limited genetic diversity of cultivated tomatoes contributes to their high susceptibility to viral infections. To address this challenge, tomato breeding programs must harness the genetic resources found in native populations and wild relatives. Breeding efforts may aim to develop broad-spectrum resistance against the virome. To identify the viruses naturally infecting 19 advanced lines, derived from native tomatoes, high-throughput sequencing (HTS) of small RNAs and confirmation with PCR and RT-PCR were used. Single and mixed infections with tomato mosaic virus (ToMV), tomato golden mosaic virus (ToGMoV), and pepper huasteco yellow vein virus (PHYVV) were detected. The complete consensus genomes of three variants of Mexican ToMV isolates were reconstructed, potentially forming a new ToMV clade with a distinct 3' UTR. The absence of reported mutations associated with resistance-breaking to ToMV suggests that the Tm-1, Tm-2, and Tm-22 genes could theoretically be used to confer resistance. However, the high mutation rates and a 63 nucleotide insertion in the 3' UTR, as well as amino acid mutations in the ORFs encoding 126 KDa, 183 KDa, and MP of Mexican ToMV isolates, suggest that it is necessary to evaluate the capacity of these variants to overcome Tm-1, Tm-2, and Tm-22 resistance genes. This evaluation, along with the characterization of advanced lines using molecular markers linked to these resistant genes, will be addressed in future studies as part of the breeding strategy. This study emphasizes the importance of using HTS for accurate identification and characterization of plant viruses that naturally infect tomato germplasm based on the consensus genome sequences. This study provides crucial insights to select appropriate disease management strategies and resistance genes and guide breeding efforts toward the development of virus-resistant tomato varieties. [ABSTRACT FROM AUTHOR]

This article develops a multi-perspective view on motivations and methods for tobamovirus purification through the ages and presents a novel, efficient, easy-to-use approach that can be well-adapted to different species of native and functionalized virions. We survey the various driving forces prompting researchers to enrich tobamoviruses, from the search for the causative agents of mosaic diseases in plants to their increasing recognition as versatile nanocarriers in biomedical and engineering applications. The best practices and rarely applied options for the serial processing steps required for successful isolation of tobamoviruses are then reviewed. Adaptations for distinct particle species, pitfalls, and 'forgotten' or underrepresented technologies are considered as well. The article is topped off with our own development of a method for virion preparation, rooted in historical protocols. It combines selective re-solubilization of polyethylene glycol (PEG) virion raw precipitates with density step gradient centrifugation in biocompatible iodixanol formulations, yielding ready-to-use particle suspensions. This newly established protocol and some considerations for perhaps worthwhile further developments could serve as putative stepping stones towards preparation procedures appropriate for routine practical uses of these multivalent soft-matter nanorods. [ABSTRACT FROM AUTHOR]

In the present study, each of the 16S ribosomal RNA (rRNA) gene sequences and random amplified polymorphic DNA (RAPD) method were used to confirm the biological classification of three Streptomyces isolates having antiviral activities against Tobacco mosaic virus (TMV). The strongest anti- TMV effect with an inhibition percentage of 97.5 was recorded for S. rochei- IS-02 followed by S. caeaoi-IS-03 (95.5%) and S. aureocirculatus-IS-01 (92.5%) at dilution ½. Lengths of 771, 663 and 693 nts were determined for the partial nucleotide sequences of 16SrRNA gene of S. aureocirculatus-IS-01, S. rochei-IS-02 and S. caeaoi-IS-03, respectively. Sequences producing significant alignments showed identities ranging from 98.41 to 100%. The phylogenetic relationship confirmed the identification of the Streptomyces isolates. A total of 85 DNA fragments (81 polymorphic and 4 monomorphic) were amplified in RAPD assay of the three Streptomyces isolates using eight random primers and contained unique DNA fragments as positive DNA markers. These DNA fragments were distributed as 48, 41 and 42 for the three isolates. The eight primers produced a total amplified DNA fragments of 85 distributed as follows 8, 10, 13, 12, 12, 10, 11 and 9 for the eight oligonucleotide primers, respectively. The similarities between the three Streptomyces species based on RAPD-PCR ranged from 66.332 to 76.158%. The phylogenetic tree showed that S. aureocirculatus-IS-01 and S. rochei-IS-2 were found together in the same cluster, while, S. caeaoi-IS-03 was found in a separate cluster. As a conclusion 16SrRNA and RAPD-PCR methods were confirmed to be more than suitable tools to differentiate between the Streptomyces species. [ABSTRACT FROM AUTHOR]

Using integrated in silico and in vitro experiments, the antiviral capabilities of green tea and licorice extracts were evaluated against the tobacco mosaic virus (TMV). It was noted that the number of induced necrotic local lesions of TMV decreased by increasing extract concentrations and thus it is considered concentration dependent on the extracts’ active compounds. Properties of eleven compounds belonging to licorice and green tea were obtained from databases to examine their activities in silico. A molecular docking simulation was performed between these agents and the protein coat of the tobacco mosaic virus (TMV). The highest effective compounds were glycyrrhetic acid, liquiritin and EGCG. ADMET studies revealed good overall properties of nine non-toxic compounds based on their predicted pharmacokinetic, physicochemical, drug-likeness and toxic properties. Based on docking energy and mode of interaction, these compounds showed strong binding with the protein coat of TMV. The antiviral effect may be due to the most effective compounds with the highest affinity namely glycyrrhetic acid, liquiritin and isoliquiritin. As a conclusion, the promising value of our titled extracts is the anti-TMV activity and pharmacokinetic and physicochemical properties of their active constituents. [ABSTRACT FROM AUTHOR]

Early and sensitive detection of tobacco mosaic virus (TMV) is of great significance for improving crop yield and protecting germplasm resources. Herein, we constructed a novel fluorescence sensor to detect TMV RNA (tRNA) through double strand specific nuclease (DSN) cycle and activator regenerative electron transfer atom transfer radical polymerization (ARGET ATRP) dual signal amplification strategy. The hairpin DNA complementarily paired with tRNA was used as a recognition unit to specifically capture tRNA. By the double‐stranded DNA hydrolyzed with DSN, tRNA is released to open more hairpin DNA, and more complementary DNA (cDNA) is bound to the surface of the magnetic beads (MBs) to achieve the first amplification. After binding with the initiator, the cDNA employed ARGET ATRP to attach more fluorescent signal molecules to the surface of MBs, thus achieving the second signal amplification. Under the optimal experimental conditions, the logarithm of fluorescence intensity versus tRNA concentration showed a good linear relationship in the range of 0.01–100 pM, with a detection limit of 1.03 fM. The limit of detection (LOD) was calculated according to LOD = 3 N/S. Besides, the sensor showed good reproducibility and stability, which present provided new method for early and highly sensitive detection for plant viruses. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus (TMV; genus Tobamovirus) is one of the most prevailing pathogens that seriously affects the quality and yield of tobacco (Nicotiana tabacum) leaves. Cross-protection using mild strains is a potential strategy for the biological prevention of plant viral diseases. Complementary mutations in attenuated strains may cause attenuated ones to suddenly evolve into virulent strains, which limits the application of cross-protection in practice. To data there has been no study on engineering the complementary mutation sites to generate stable attenuated mutants for cross-protection. In this study, we found that the substitution of the conserved arginine at position 88 (R88) in p126 protein with alanine (A) abolished the cell-to-cell movement and reduced the replication of TMV. However, a spontaneous complementary mutation of serine at position 114 (S114) to lysine (K) in p126 restored TMV virulence. Substitution of S114 with R in p126 restored the systemic infection but not the virulence of TMV, therefore, the mutant TMV-R88A/S114R was an attenuated one. Furthermore, our results showed that TMV-R88A/S114R was a stable attenuated mutant, and could effectively protect tobacco plants against the wild-type TMV infection. This study reports a promising TMV mild mutant for cross-protection in tobacco plants by modifying the complementary mutation site in p126. [ABSTRACT FROM AUTHOR]

Introduction: The study investigates the potential of Plasma Activated Water (PAW) as an innovative irrigation medium to enhance growth and defense responses in tomato seedlings. It explores PAW's utility in both healthy seedlings and those inoculated with Tomato mottle mosaic virus (ToMMV). Methods: PAW, produced through a dielectric barrier volume discharge, serves as a chemical-free alternative to traditional fertilizers. Tomato seedlings were irrigated with PAW or control solutions. The study employs biometric measurements to assess growth and biochemical analysis to evaluate antioxidant levels and pigments. Gene expression analysis was conducted to evaluate the plant response, while the distribution of macro and micronutrients was assessed through micro X-ray fluorescence. Results and discussion: Results indicate that PAW-irrigated seedlings exhibit significant growth enhancement compared to those receiving conventional fertilization. Increased levels of antioxidant molecules and pigments suggest improved photosynthetic activity and stress tolerance. Gene expression analysis shows up-regulation of defense genes in PAW-treated plants postviral infection. The up-regulation of defense genes and the restoration of mineral nutrient distribution in PAW-treated, virus-infected plants highlight PAW's role in enhancing plant resilience against pathogens and mitigating nutrient deficiencies. These findings emphasize PAW's potential as a sustainable agricultural solution, promoting plant growth, enhancing defense mechanisms, and reducing biotic stress due to virus infections. [ABSTRACT FROM AUTHOR]