Search

The present study described molecular characterization of two potyviruses: wild tomato mosaic virus Dehong isolate (WTMV‐Dh) and chilli veinal mottle virus Dehong isolate (ChiVMV‐Dh) mix‐infection chilli pepper and assessed their mix‐infection on chilli pepper. Transcriptome next‐generation sequencing technology (NGS) and RT‐PCR were used to obtain the complete genome sequences of the abovementioned two viruses. The results showed that the complete sequence of WTMV‐Dh is 9675 nucleotides (nt) in length and encodes a complete polyprotein of 3075 amino acids (aa). The WTMV‐Dh polyprotein shares 76.1%–82.6% nt and 85.3%–89.5% aa identities with three previously reported WTMV isolates. The complete sequence of ChiVMV‐Dh is 9736 nt in length and encodes a complete polyprotein with 3, 089 aa. ChiVMV‐Dh polyprotein shares 80.8%–92.2% nt and 85.3%–95.6% aa identities with previously reported ChiVMV isolates. Following phylogenetic analysis based on the polyprotein sequences of potyviruses revealed that WTMV‐Dh clustered with the Vietnam strain WTMV‐Laichau, while ChiVMV‐Dh clustered with several ChiVMV Sichuan isolates. The mix‐inoculation experiment showed that the mix‐infection of these two viruses has more severe symptoms than single‐infection. [ABSTRACT FROM AUTHOR]

Plant virus diseases seriously affect the yield and quality of agricultural products, and their prevention and control are difficult. It is urgent to develop new and efficient antiviral agents. In this work, a series of flavone derivatives containing carboxamide fragments were designed, synthesized, and systematically evaluated for their antiviral activities against tobacco mosaic virus (TMV) on the basis of a structural–diversity–derivation strategy. All the target compounds were characterized by 1H-NMR, 13C-NMR, and HRMS techniques. Most of these derivatives displayed excellent in vivo antiviral activities against TMV, especially 4m (inactivation inhibitory effect, 58%; curative inhibitory effect, 57%; and protection inhibitory effect, 59%), which displayed similar activity to ningnanmycin (inactivation inhibitory effect, 61%; curative inhibitory effect, 57%; and protection inhibitory effect, 58%) at 500 μg mL−1; thus, it emerged as a new lead compound for antiviral research against TMV. Antiviral mechanism research by molecular docking demonstrated that compounds 4m, 5a, and 6b could interact with TMV CP and disturb virus assembly. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum) plants from a commercial glasshouse were identified with symptoms compatible with a tomato brown rugose fruit virus (ToBRFV) infection. Reverse transcription-PCR and quantitative PCR confirmed the presence of ToBRFV. Subsequently, the same RNA sample and a second from tomato plants infected with a similar tobamovirus, tomato mottle mosaic virus (ToMMV), were extracted and processed for high-throughput sequencing with the Oxford Nanopore Technology (ONT). For the targeted detection of ToBRFV, the two libraries were synthesized by using six ToBRFV sequence-specific primers in the reverse transcription step. This innovative target enrichment technology enabled deep coverage sequencing of ToBRFV, with 30% of the total reads mapping to the target virus genome and 57% mapping to the host genome. The same set of primers applied to the ToMMV library generated 5% of the total reads mapping to the latter virus, indicating that sequencing of similar, non-target viral sequences was also allowed. Further, the complete genome of pepino mosaic virus (PepMV) was also sequenced from the ToBRFV library, thus suggesting that, even using multiple sequence-specific primers, a low rate of off-target sequencing can usefully provide additional information on unexpected viral species coinfecting the same samples in an individual assay. These results demonstrate that targeted nanopore sequencing can specifically identify viral agents and has sufficient sensitivity towards non-target organisms to provide evidence of mixed virus infections. [ABSTRACT FROM AUTHOR]

Phytophthora infestans is the oomycete responsible for late blight disease of Solanaceae that causes both yield and economic losses. With the aim of reducing plant wilt and high management costs mainly due to wide fungicide applications, alternative eco-sustainable control strategies are needed. RNA interference (RNAi) is a powerful tool for gene function studies that can be accomplished by constitutive transformation or transient expression such as virus-induced gene silencing (VIGS) experiments. VIGS makes use of viruses to deliver sequences homologous to a target gene fragment and trigger RNAi. Indeed, a P. infestans ortholog of plant loricrin-like protein (LLP), named PiLLP, has been silenced using the direct infection of a recombinant vector based on the plant virus tobacco mosaic virus (TMV-PiLLP-1056), aiming to reduce the oomycete sexual reproduction. For this purpose, the gene coding for the green fluorescent protein (GFP) present in the TMV-GFP-1056 vector has been replaced with an antisense construct obtained by fusion PCR of the PiLLP 5′-UTR and 3′-UTR sequences. Here, we show that RNAi can be expressed in the A1 mating type of P. infestans strain 96.9.5.1 by VIGS using the direct infection of TMV-PiLLP-1056. We provide evidence that the recombinant vector can enter, replicate, and persist in mycelia of P. infestans where it induces the partial downregulation of the PiLLP transcript. Compared with the wild-type, the PiLLP-silenced A1 mating type had slower colony growth and a diminished virulence in detached tomato leaflets. This seems to be the first evidence of a constitutive gene downregulation of P. infestans using a recombinant vector based on a plus-sense RNA plant virus. [ABSTRACT FROM AUTHOR]

Viral infection, which entails synthesis of viral proteins and active reproduction of the viral genome, effects significant changes in the functions of many intracellular systems in plants. Along with these processes, a virus has to suppress cellular defense to create favorable conditions for its successful systemic spread in a plant. The virus exploits various cellular factors of a permissive host modulating its metabolism as well as local and systemic transport of macromolecules and photoassimilates. The Nicotiana benthamiana stress-induced gene encoding Kunitz peptidase inhibitor-like protein (KPILP) has recently been shown to be involved in chloroplast retrograde signaling regulation and stimulation of intercellular transport of macromolecules. In this paper we demonstrate the key role of KPILP in the development of tobamovius infection. Systemic infection of N. benthamiana plants with tobacco mosaic virus (TMV) or the closely related crucifer-infecting tobamovirus (crTMV) induces a drastic increase in KPILP mRNA accumulation. KPILP knockdown significantly reduces the efficiency of TMV and crTMV intercellular transport and reproduction. Plants with KPILP silencing become partially resistant to tobamovirus infection. Therefore, KPILP could be regarded as a novel proviral factor in the development of TMV and crTMV infection in N. benthamiana plants.

Plant virus-based nanoparticles (VNPs) offer a bioinspired approach to the delivery of drugs and imaging agents. The chemical addressability, biocompatibility, and scalable manufacturability of VNPs make them a promising alternative to synthetic delivery platforms. However, VNPs, just like other proteinaceous or synthetic nanoparticles (NPs), are readily recognized and cleared by the immune system and mechanisms such as opsonization and phagocytosis. Shielding strategies, such as PEGylation, are commonly used to mitigate premature NP clearance. Here, we investigated polyethylene glycol (PEG) coatings on the tobacco mosaic virus (TMV), which was used as a model nanocarrier system. Specifically, we evaluated the effects of linear and multivalent PEG coatings at varying chain lengths on serum protein adsorption, antibody recognition, and macrophage uptake. Linear and multivalent PEGs of molecular weights 2,000 and 5,000 Da were successfully grafted onto the TMV at ≈ 20%–60% conjugation efficiencies, and the degree of cross-linking as a function of PEG valency and length was determined. PEGylation resulted in the modulation of TMV–macrophage interactions and reduced corona formation as well as antibody recognition. Linear and multivalent PEG 5,000 formulations (but not PEG 2,000 formulations) reduced α-TMV antibody recognition, whereas shorter, multivalent PEG coatings significantly reduced α-PEG recognition—this highlights an interesting interplay between the NP and the PEG itself in potential antigenicity and should be an important consideration in PEGylation strategies. This work provides insight into the PEGylation of VNPs, which may improve the possibility of their implementation in clinical applications.

These 10 PVY isolates had one to four amino acid differences from the epitope recognized by MAb N1 but contained the epitope recognized by M1 and M2. Keywords: cocktail; detection; epitope; monoclonal antibody; potato virus Y; serology EN cocktail detection epitope monoclonal antibody potato virus Y serology 1725 1727 3 08/23/23 20230901 NES 230901 Antibody-based serological methods, including enzyme-linked immunosorbent assay (ELISA), dot immunobinding assay (DIBA) and Western blot, play an essential role in the detection of plant viruses. [Extracted from the article]

Nucleotide-binding leucine-rich repeat (NLR) immune receptors play a critical role in defence against pathogens in plants and animals. However, we know very little about NLR-interacting proteins and the mechanisms that regulate NLR levels. Here, we used proximity labeling (PL) to identify the proteome proximal to N, which is an NLR that confers resistance to Tobacco mosaic virus (TMV). Evaluation of different PL methods indicated that TurboID-based PL provides more efficient levels of biotinylation than BioID and BioID2 in plants. TurboID-based PL of N followed by quantitative proteomic analysis and genetic screening revealed multiple regulators of N-mediated immunity. Interestingly, a putative E3 ubiquitin ligase, UBR7, directly interacts with the TIR domain of N. UBR7 downregulation leads to an increased amount of N protein and enhanced TMV resistance. TMV-p50 effector disrupts the N-UBR7 interaction and relieves negative regulation of N. These findings demonstrate the utility of TurboID-based PL in plants and the N-interacting proteins we identified enhance our understanding of the mechanisms underlying NLR regulation.

Large doses of chemical pesticides are required to achieve effective concentrations in the rhizosphere, which results in the accumulation of harmful residues. Precision farming is needed to improve the efficacy of pesticides, but also to avoid environmental pollution, and slow-release formulations based on nanoparticles offer one solution. Here, we tested the mobility of synthetic and virus-based model nanopesticides by combining soil column experiments with computational modelling. We found that the tobacco mild green mosaic virus and cowpea mosaic virus penetrate soil to a depth of at least 30 cm, and could therefore deliver nematicides to the rhizosphere, whereas the Physalis mosaic virus remains in the first 4 cm of soil and would be more useful for the delivery of herbicides. Our experiments confirm that plant viruses are superior to synthetic mesoporous silica nanoparticles and poly(lactic-co-glycolic acid) for the delivery and controlled release of pesticides, and could be developed as the next generation of pesticide delivery systems.

Nanotheranostic reagents that integrate magnetic resonance imaging (MRI) and photothermal therapy (PTT) offer a promising strategy for the treatment of human disease. However, classic gadolinium (Gd)-based T1-MRI contrast agents are limited by their low relaxivity. To address this, we produced Gd-loaded Tobacco mosaic virus (TMV) particles coated with the mussel-inspired biopolymer polydopamine (PDA). Such biocompatible nanotheranostic reagents can be used to facilitate PTT, guided by multimodal magnetic resonance/photoacoustic imaging. The r1-relaxivity of the Gd-TMV-PDA particles at 60 MHz was ∼80 mM-1 s-1, compared to 13.63 mM-1 s-1 for the uncoated Gd-TMV particles. The Gd-TMV-PDA particles also promoted strong near-infrared absorption with high photothermal conversion efficiency (28.9%) and demonstrated excellent photoacoustic contrast. Multimodal imaging and PTT resulted in the effective killing of PC-3 prostate cancer cells. Gd-TMV-PDA nanoparticles therefore offer a promising theranostic approach that can now be tested in vivo in cancer models.

We present molecular mechanics and spectroscopic calculations on prototype artificial light harvesting systems consisting of chromophores attached to a tobacco mosaic virus (TMV) protein scaffold. These systems have been synthesized and characterized spectroscopically, but information about the microscopic configurations and geometry of these TMV-templated chromophore assemblies is largely unknown. We use a Monte Carlo conformational search algorithm to determine the preferred positions and orientations of two chromophores, Coumarin 343 together with its linker and Oregon Green 488, when these are attached at two different sites (104 and 123) on the TMV protein. The resulting geometric information shows that the extent of disorder and aggregation properties and therefore the optical properties of the TMV-templated chromophore assembly are highly dependent on both the choice of chromophores and the protein site to which they are bound. We use the results of the conformational search as geometric parameters together with an improved tight-binding Hamiltonian to simulate the linear absorption spectra and compare with experimental spectral measurements. The ideal dipole approximation to the Hamiltonian is not valid because the distance between chromophores can be very small. We found that using the geometries from the conformational search is necessary to reproduce the features of the experimental spectral peaks.

Glioblastoma is a particularly challenging cancer, as there are currently limited options for treatment. New delivery routes are being explored, including direct intratumoral injection via convection-enhanced delivery (CED). While promising, convection-enhanced delivery of traditional chemotherapeutics such as doxorubicin (DOX) has seen limited success. Several studies have demonstrated that attaching a drug to polymeric nanoscale materials can improve drug delivery efficacy via CED. We therefore set out to evaluate a panel of morphologically distinct protein nanoparticles for their potential as CED drug delivery vehicles for glioblastoma treatment. The panel consisted of three different virus-like particles (VLPs), MS2 spheres, tobacco mosaic virus (TMV) disks and nanophage filamentous rods modified with DOX. While all three VLPs displayed adequate drug delivery and cell uptake in vitro, increased survival rates were only observed for glioma-bearing mice that were treated via CED with TMV disks and MS2 spheres conjugated to doxorubicin, with TMV-treated mice showing the best response. Importantly, these improved survival rates were observed after only a single VLP⁻DOX CED injection several orders of magnitude smaller than traditional IV doses. Overall, this study underscores the potential of nanoscale chemotherapeutic CED using virus-like particles and illustrates the need for further studies into how the overall morphology of VLPs influences their drug delivery properties.

Melatonin is a multifunctional and ubiquitous molecule. In animals, melatonin is a hormone that is involved in a wide range of physiological activities and is also an excellent antioxidant. In plants, it has been considered a master regulator of multiple physiological processes as well as of hormonal homeostasis. Likewise, it is known for its role as a protective biomolecule and activator of tolerance and resistance against biotic and abiotic stress in plants. Since infections by pathogens such as bacteria, fungi and viruses in crops result in large economic losses, interest has been aroused in determining whether melatonin plays a relevant role in plant defense systems against pathogens in general, and against viruses in particular. Currently, several strategies have been applied to combat infection by pathogens, one of them is the use of eco-friendly chemical compounds that induce systemic resistance. Few studies have addressed the use of melatonin as a biocontrol agent for plant diseases caused by viruses. Exogenous melatonin treatments have been used to reduce the incidence of several virus diseases, reducing symptoms, virus titer, and even eradicating the proliferation of viruses such as Tobacco Mosaic Virus, Apple Stem Grooving Virus, Rice Stripe Virus and Alfalfa Mosaic Virus in tomato, apple, rice and eggplant, respectively. The possibilities of using melatonin as a possible natural virus biocontrol agent are discussed. [ABSTRACT FROM AUTHOR]

In summer 2021, six varieties of peony plants exhibiting severe leaf rolling and deformation, as well as severe plant dwarfism and mosaics were observed in Kyiv region of Ukraine. Using DAS-ELISA, these plants were tested for the presence of 12 viruses (bean yellow mosaic virus, cucumber mosaic virus, tobacco mosaic virus, alfalfa mosaic virus, tobacco ring spot virus, raspberry bushy dwarf virus, strawberry latent ringspot virus, raspberry ringspot virus, cherry leaf roll virus, tobacco rattle virus, tomato spotted wilt virus, and wheat dwarf virus). The DAS-ELISA tests showed the absence of the above viruses. Using TEM, filamentous viral particles of 1200 ± 50 × 12 nm were revealed in leaf sap of peony plants of the variety Zhemchuzhnyi Rozsyp with symptoms of dwarfism, leaf rolling and deformation. Using DAS-ELISA and real-time PCR, grapevine leaf roll-associated virus-3 (GLRaV-3) was detected in these plants. This is the first report of GLRaV-3 on peony plants in Ukraine and, to our knowledge, in the world. [ABSTRACT FROM AUTHOR]

With the expansion of protected vegetable growing areas (PVGAs), viral plant diseases have become more prevalent, causing severe economic losses to the vegetable production industry in China. At present, researches on plant viruses mainly focus on plants, but there is only a few reports on the species of viruses in surface water from PVGAs. The surface water samples in PVGAs are representative to a certain extent, which has an important reference value for studying the characteristics of plant viruses in surface water. The purpose of this study was to identify the diversity and the possibility of entering disease infection cycle of plant viruses in water samples collected from PVGAs in eastern China. A total of 144 water samples were collected, and eight plant viruses including tobacco mosaic virus (TMV, 8.33%), cucumber green mottle mosaic virus (CGMMV, 33.33%), pepper mild mottle virus (PMMoV, 6.94%), cucumber mosaic virus (CMV, 0.69%), tomato masaic virus (ToMV, 3.47%), tomato mottle mosaic virus (ToMMV, 0.69%), tomato chlorosis virus (ToCV, 4.17%), and tomato yellow leaf curl virus (TYLCV, 5.56%) were examined using RT-PCR and PCR. The species of viruses in surface water varied greatly by location. CGMMV, TMV, ToCV, ToMV, ToMMV, and TYLCV were identified in Shandong, a northern part of Eastern China, whereas only PMMoV was found in Shanghai, a southern part of Eastern China. After healthy tobacco plants were inoculated with the concentrated solutions of TMV, ToMV, CGMMV, and PMMoV, could cause disease in healthy tobacco, indicating that the plant viruses in the concentrated solution have the infectivity, and the plant viruses in surface water have the possibility of entering the infection cycle of disease. The results will improve the understanding of the potential risks of waterborne disease transmission. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome (PRRS) is a disease leading to spontaneous abortions and stillbirths in sows and lowered life quality and expectancy in growing pigs. PRRS is prevalent worldwide and has significant economic impacts to swine industries around the globe. Co-expression of the two most abundant proteins in the viral envelope, the matrix protein (M) and glycosylated protein 5 (GP5), can produce a neutralizing immune response for the virus providing a potentially effective subunit vaccine against the disease, but these proteins are difficult to express. The goal of this research was to display antigenic portions of the M and GP5 proteins on the surface of tobacco mosaic virus-like particles. A modified tobacco mosaic virus coat protein (TMVc) was transiently expressed in Nicotiana benthamiana leaves and targeted to three subcellular compartments along the secretory pathway to introduce glycosylation patterns important for M-GP5 epitope immunogenicity. We found that accumulation levels in the apoplast were similar to the ER and the vacuole. Because glycans present on plant apoplastic proteins are closest to those present on PRRSV proteins, a TMVcM-GP5 fusion construct was targeted to the apoplast and accumulated at over 0.5 mg/g of plant fresh weight. TMVc virus-like particles self-assembled in plant cells and surface-displayed the M-GP5 epitope, as visualized by transmission electron microscopy and immunogold localization. These promising findings lay the foundation for immunogenicity and protective-immunity studies in animals to examine the efficacy of this vaccine candidate as a measure to control PRRS. [ABSTRACT FROM AUTHOR]

Nucleotide-binding leucine-rich repeat (NLR) receptor-mediated immunity includes rapid production of reactive oxygen species (ROS) and transcriptional reprogramming, which is controlled by transcription factors (TFs). Although some TFs have been reported to participate in NLR-mediated immune response, most TFs are transcriptional activators, and whether and how transcriptional repressors regulate NLR-mediated plant defenses remains largely unknown. Here, we show that the Alfin-like 7 (AL7) interacts with N NLR and functions as a transcriptional repressor. Knockdown and knockout of AL7 compromise N NLR-mediated resistance against tobacco mosaic virus, whereas AL7 overexpression enhances defense, indicating a positive regulatory role for AL7 in immunity. AL7 binds to the promoters of ROS scavenging genes to inhibit their transcription during immune responses. Mitogen-activated protein kinases (MAPKs), salicylic acid-induced protein kinase (SIPK), and wound-induced protein kinase (WIPK) directly interact with and phosphorylate AL7, which impairs the AL7-N interaction and enhances its DNA binding activity, which promotes ROS accumulation and enables immune activation. In addition to N, AL7 is also required for the function of other Toll interleukin 1 receptor/nucleotide-binding/leucine-rich repeats (TNLs) including Roq1 and RRS1-R/RPS4. Our findings reveal a hitherto unknown MAPK-AL7 module that negatively regulates ROS scavenging genes to promote NLR-mediated immunity. [ABSTRACT FROM AUTHOR]

The necrogenic strain N5 of tomato mosaic virus (ToMV-N5) causes systemic necrosis in tomato cultivar Hezuo903. In this work, we mapped the viral determinant responsible for the induction of systemic necrosis. By exchanging viral genes between N5 and a non-necrogenic strain S1, we found that movement protein (MP) was the determinant for the differential symptoms caused by both strains. Compared with S1 MP, N5 MP had an additional ability to increase virus accumulation, which was not due to its functions in viral cell-to-cell movement. Actually, N5 MP, but not S1 MP, was a weak RNA silencing suppressor, which assisted viral accumulation. Sequence alignment showed that both MPs differed by only three amino acid residues. Experiments with viruses having mutated MPs indicated that the residue isoleucine at position 170 in MP was the key site for MP to increase virus accumulation, but also was required for MP to induce systemic necrosis in virus-infected tomato plants. Collectively, the lethal necrosis caused by N5 is dependent on its MP protein that enhances virus accumulation via its RNA silencing suppressor activity, probably leading to systemic necrosis responses in tomato plants. [ABSTRACT FROM AUTHOR]

The transcription factor SHE1 was induced by tobacco mosaic virus (TMV) infection in tobacco cv. Samsun NN (SNN) and SHE1 inhibited TMV accumulation when expressed constitutively. To better understand the role of SHE1 in virus infection, transgenic SNN tobacco plants generated to over-express SHE1 (OEx-SHE1) or silence expression of SHE1 (si-SHE1) were infected with TMV. OEx-SHE1 affected the local lesion resistance response to TMV, whereas si-SHE1 did not. However, si-SHE1 allowed a slow systemic infection to occur in SNN tobacco. An inhibitor of virus replication (IVR) was known to reduce the accumulation of TMV in SNN tobacco. Analysis of SHE1 and IVR mRNA levels in OEx-SHE1 plants showed constitutive expression of both mRNAs, whereas both mRNAs were less expressed in si-SHE1 plants, even after TMV infection, indicating that SHE1 and IVR were associated with a common signaling pathway. SHE1 and IVR interacted with each other in four different assay systems. The yeast two-hybrid assay also delimited sequences required for the interaction of these two proteins to the SHE1 central 58-79% region and the IVR C-terminal 50% of the protein sequences. This suggests that SHE is a transcription factor involved in the induction of IVR and that IVR binds to SHE1 to regulate its own synthesis. [ABSTRACT FROM AUTHOR]

Plant nucleotide-binding, leucine-rich, repeat-containing proteins (NLRs) play important roles in plant immunity. NLR expression and function are tightly regulated by multiple mechanisms. In this study, a conserved serine/arginine-rich protein (SR protein) was identified through the yeast one-hybrid screening of a tobacco cDNA library using DNA fragments from the N gene, an NLR that confers immunity to tobacco mosaic virus (TMV). This SR protein showed an interaction with a 3′ genomic regulatory sequence (GRS) and has a potential role in regulating the alternative splicing of N. Thus, it was named SR regulator for N, abbreviated SR4N. Further study showed that SR4N plays a positive role in N-mediated cell death but a negative role in N protein accumulation. SR4N also promotes multiple virus replications in co-expression experiments, and this enhancement may not function through RNA silencing suppression, as it did not enhance 35S-GFP expression in co-infiltration experiments. Bioinformatic and molecular studies revealed that SR4N belongs to the SR2Z subtype of the SR protein family, which was conserved in both dicots and monocots, and its roles in repressing viral immunity and triggering cell death were also conserved. Our study revealed new roles for SR2Z family proteins in plant immunity against viruses. [ABSTRACT FROM AUTHOR]

Research on natural compounds provides new alternatives for effective and sustainable control of plant viral pathogens. Herein, we prepared and investigated the in vitro antiviral activity of 60 plant species from 22 families. The hydroethanolic extracts of Rhus coriaria, Chenopodium quinoa and Ailanthus altissima have strong inhibitions on Tobacco Mosaic Virus (TMV) infection. Hydroethanolic extract of C. quinoa with half-maximal Effective Concentration (EC50) value of 1.64 mg mL-1 exhibited the highest inhibitory effect against TMV. The extracts of R. coriaria and A. altissima with EC50 values of 2.82 and 4.42 mg mL-1, being compared with C. quinoa, showed an anti-TMV activity at higher concentrations, respectively. The systemic assay indicated that all of the three extracts reduced the symptoms and negative effects of TMV on tobacco plants. The chemical analysis of C. quinoa extract demonstrated a rich profile of saponins and anthocyanins, while A. altissima and R. coriaria extracts were rich in phenolic compounds. These results displayed that C. quinoa, R. coriaria, and A. altissima extracts had significant antiviral activity, and could be used as suitable sources for discovering new antiviral agents. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV) causes significant damage and yield losses in peppers. The objective of this study is to determine the efficiency of prevalent aphid species occurring in pepper fields to transmit this virus within pepper plants and to identify their vector pressure in order to target the critical species implicated in CMV epidemics spread. Alatae and apterae were monitored in an experimental pepper field in northern Tunisia for 3 years. Sixty‐eight species were captured in winged form in yellow water traps. The most abundant species were Myzus persicae, Aphis gossypii, Aphis fabae, Aphis spiraecola, Acyrthosiphon pisum, Metopolophium dirhodum, Rhopalosiphum maidis, Aphis craccivora, Aphis nerii, Hyalopterus pruni, Sitobion avenae and Rhopalosiphum padi constituting 90% of aphid populations in the field. Their temporal dynamic showed a high period of flight activity from April to June and a second peak in September was registered. Two of these species, M. persicae and A. gossypii were also found in their wingless form on pepper leaves with a prevalence of 99.5% and 0.5%, respectively. The 12 most abundant aphid species were tested for their transmission efficiency of CMV (CMV‐pepp2 isolate) with A. gossypii as a reference vector. All aphids tested, including colonizing and non‐colonizing species on pepper, were verified to be vectors of this isolate. However, significant differences in the transmission efficiency were found between the aphid species (p <.001, SE = 7.29). M. persicae (60%) scored the highest transmission efficiency rate. Additionally, A. fabae solanella (50%) had higher transmission efficiency than the reference vector, A. gossypii (40%). H. pruni (16.67%) was documented as a new CMV vector to pepper. The single‐aphid transmission probabilities ranged from 0.7% to 16.7%. The calculated mean Vector Pressure Index (VPI) for these 12 species showed a stronger relationship with the specific aphid population variance (R = 0.89, p <.01) than the variation of the specific single‐aphid transmission probabilities (R = 0.62, p <.05). Indeed, for alate non‐colonizer vectors, A. spiraecola has recorded the highest mean VPI (27.5), despite its moderate transmission efficiency (23.33%). Nevertheless, for colonizer vectors in both winged and wingless forms, M. persicae had the highest mean VPI (49.26) of all vector species and was mostly present in its apterous form. The 12 vector species contributed to a total mean VPI of 133.48 during the surveyed periods. This research determined key features of CMV epidemiology in pepper crops that might be helpful for CMV disease management at an early stage. [ABSTRACT FROM AUTHOR]

A facile enzyme-mediated strategy enables site-specific covalent one-step coupling of genetically tagged luciferase molecules to coenzyme A-modified tobacco mosaic virus (TMV-CoA) both in solution and on solid supports. Bacillus subtilis surfactin phosphopantetheinyl transferase Sfp produced in E. coli mediated the conjugation of firefly luciferase N-terminally extended by eleven amino acids forming a 'ybbR tag' as Sfp-selective substrate, which even worked in bacterial raw lysates. The enzymes displayed on the protein coat of the TMV nanocarriers exhibited high activity. As TMV has proven a beneficial high surface-area adapter template stabilizing enzymes in different biosensing layouts in recent years, the use of TMV-CoA for fishing ybbR-tagged proteins from complex mixtures might become an advantageous concept for the versatile equipment of miniaturized devices with biologically active proteins. It comes along with new opportunities for immobilizing multiple functionalities on TMV adapter coatings, as desired, e.g., in handheld systems for point-of-care detection. [Display omitted] • CoA-modified tobacco mosaic virus (TMV): facile enzymatic luciferase coupling. • Convenient, efficient one-pot reaction: Sfp installs peptide ybbR-tagged luciferase. • Orthogonal conjugation of active ybbR-Luc to TMV-CoA works also on solid surfaces. • Process can be eased and speeded up by using target protein in raw cell extract. • Prospects: Sfp-enabled versatile enzyme coupling to TMV-CoA adapters on biochips?! [ABSTRACT FROM AUTHOR]

Involving the natural host-resistance mechanisms to pathogens are essential and one of the most promising approaches in development of first-line defenses against viral plant diseases. Polysaccharides isolated from natural sources are considered the most active resistance inducers. The biological activity of polysaccharides depends on the nature and chemical structure of the constituent components of complex preparations. In this view, the objective of our study was to evaluate the biological activity of complex preparations composed of glycans, rhamnolipids, and thiosulfonates as inducers of natural plant resistance and inhibitors of tobacco mosaic virus (TMV). Complex preparations were obtained using the following components: biogenic glycolipids - rhamnolipids of the Pseudomonas sp. strain PS-17, glycans - Ganoderma adspersum glucan and Candida maltosa mannan, as well as synthetic biocides - thiosulfonates (methylthiosulfanilate). The biological activity of the preparations was investigated in the host-virus model system Nicotiana tabacum L. and TMV. It was shown that preparations at concentrations of 10 and 100 µg mL-1 were active plant resistance inducers in N. tabacum cv. Immune 580, hypersensitive to TMV. At the same concentrations, complex preparations also reduced infectivity of TMV on Datura metel L. acting as viral infection inhibitors. The inducing activity of the complex preparations is sensitive to well-known transcription inhibitor actinomycin D (10 µg mL-1). This fact may indicate the important role of RNA synthesis in the activation of plant virus resistance by the studied preparations. [ABSTRACT FROM AUTHOR]

One effect of viral infection on plant physiology is increased stomata closure so that the transpiration rate is low, which in turn causes an increase in leaf temperature. Changes in plant leaf temperature can be measured by thermography using high-resolution thermal cameras. The results can be used as an indicator of virus infection, even before the appearance of visible symptoms. However, the higher the sensor resolution of the thermal camera, the more expensive it is, which is an obstacle in developing the method more widely. This article describes the potential of thermography in detecting Tobacco mosaic virus infection in chilipepper plants using a low-cost camera. A FLIR C2 camera was used to record images of plants in two treatment groups, non-inoculated (V0) and virusinoculated plants (V1). Significantly, V1 had a lower temperature at 8 and 12 days after inoculation (dai) than those of V0, but their temperature was higher than V0 before symptoms were visible, i.e., at 17 dai. Thermography using low-cost thermal cameras has potency to detect early viral infection at 8 dai with accuracy levels (AUC) of 80.0% and 86.5% based on k-Nearest Neighbors and Naïve Bayes classifiers, respectively. [ABSTRACT FROM AUTHOR]

Since the discovery of the tobacco mosaic virus in the 1890s, awareness has grown in regard to how viruses affect the environment. Viral infections are now known to cause various effects besides pathogenicity, with some viruses in fact having a beneficial impact on plants. Although research has focused on disease-causing viruses that can infect plants, many wild plants are also infected with non-pathogenic viral agents. Traditionally, abiotic, and biotic stresses have been studied as isolated stimuli that trigger signaling pathways within the plant. However, both biotic and abiotic stress can trigger complex molecular interactions within plants, which in turn drive interconnected response pathways. Here, we demonstrate that heat-killed tobacco mosaic virus (TMV) can increase abiotic stress tolerance in plants, an effect that could potentially be implemented in challenging growth environments. To our knowledge, this is the first report of plant abiotic stress tolerance following treatment with heat-killed viral particles. [ABSTRACT FROM AUTHOR]

Tobacco (Nicotiana tabacum L.) is an important industrial crop. Among the diseases causing losses in tobacco cultivation, viral ones are of particular importance due to the very low effectiveness of chemical protection allowing only for vector control. The greatest threat to tobacco cultivation in Poland and in many countries of the world is posed by potato virus Y (PVY), tomato spotted wilt virus (TSWV) and, in recent years, the increasingly frequent tobacco mosaic virus (TMV). The genetic resources studies carried out in the genus Nicotiana have shown a wide variation in species resistance, assessed biologically, serologically and molecularly, depending on the virus used and, in the case of PVY, also on the specific isolate. The results of the assessment of resistance in Nicotiana accessions presented in this paper, gathered from literature data as well as from our own research, allow us to broaden and systematise our knowledge on the sources of resistance to viral diseases. This is the only such an extensive study in this field. It provides an excellent information base for the appropriate selection of accessions for use in resistance breeding. [ABSTRACT FROM AUTHOR]

Background: With the long‐term use of traditional bactericides and antiviral agents, drug resistance has become increasingly prominent, resulting in impaired crop growth and yields. Based on this, the introduction of small molecular active groups into natural products has become the direction of research for green pesticides. Results: In this study, novel 1,3,4‐oxadiazole sulfonate/carboxylate flavonoid derivatives were explored. Among them, D4 exhibited good inhibitory effects on plant bacteria. It is worth mentioning that D4 (15 μg ml−1) exhibited an excellent median effective concentration (EC50) value against Xanthomonas oryzae pv. oryzae (Xoo), which was better than bismerthiazol (73 μg ml−1) and thiodiazole copper (100 μg ml−1). The EC50 for D4 was much lower than the two positive controls (bismerthiazol, thiodiazole copper), making D4 more potent in this assay of bacterial growth inhibition. In addition, mechanism research using scanning electron microscopy revealed that D4 could cause deformation or rupture of the cell membranes of Xoo and Pseudomonas syringae pv. actinidiae. Moreover, D4 exhibited the best EC50 for in vivo curative (132 μg ml−1) and protective (101 μg ml−1) activities against tobacco mosaic virus, which were more effective than ningnanmycin. Microscale thermophoresis data suggested that D4 [dissociation constant (Kd) = 0.038 ± 0.011 μmol L−1] exhibited a stronger binding capacity than the control agent ningnanmycin (Kd = 4.707 ± 2.176 μmol L−1). Conclusion: The biological activity data and mode of action demonstrated that D4 had the best antibacterial and antiviral effects. Compound D4 discovered in the current work may be a very promising agricultural drug. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of the study is to analyze and investigate viral pathogens on tomatoes and peppers to detect Tomato Brown Rugose Fruit Virus (ToBRFV) in seeds and plant samples. The only hosts of Tomato brown rugose fruit virus are tomato (Solanum lycopersicum L.) and pepper (Capsicum annuum L.). The spread of ToBRFV carries major risks in tomato and pepper cultivation which are important crops grown in Europe. The symptoms resemble those of other viral infections, such as Tomato Mosaic virus, Pepino Mosaic virus and others found in Bulgaria. To achieve the aim of the study and establish ToBRFV over the two-year period, laboratory analyses were performed on more than 28 seed samples of tomates and peppers, imported or in movement within the EC. About 47 plant samples from greenhouses, with the origin of the plants from other countries, were also analyzed. Samples were tested using the ELISA method for five viruses. As a result of this mass screening, the ToBRFV virus was detected on tomato seeds in Bulgaria for the first time. On the recommendation by the phytosanitary authorities, the infected seeds and the tomato plants produced from them were destroyed in order to prevent and limit the future spread of Tomato Brown Rugose Fruit Virus on the territory of Bulgaria. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus movement protein (TMV MP) is essential for virus spread between cells. To accomplish its task, TMV MP binds viral RNA, interacts with components of the cytoskeleton, and increases the size exclusion limit (SEL) of plasmodesmata. Plasmodesmata are gated intercellular channels that allow passage of small molecules and macromolecules, including RNA and protein, between plant cells. Moreover, plasmodesmata are diverse and those connecting different cell types appear to have unique mechanisms to regulate macromolecular trafficking, which likely contributes to the establishment of distinct cell boundaries. Consequently, TMV MP might be competent to mediate RNA transport through some but not all plasmodesmal gates. Due to a lack of viral mutants defective for movement between specific cell types, the ability of TMV MP in this regard is incompletely understood. In contrast, a number of trafficking impaired Potato spindle tuber viroid (PSTVd) mutants have been identified. PSTVd is a systemically infectious non-coding RNA that nevertheless can perform all functions required for replication as well as cell-to-cell and systemic spread. Previous studies have shown that PSTVd employs different structure and sequence elements to move between diverse cell types in host plants, and mutants defective for transport between specific cell types have been identified. Therefore, PSTVd may serve as a tool to analyze the functions of MPs of viral and cellular origin. To probe the RNA transport activity of TMV MP, transgenic plants expressing the protein were inoculated with PSTVd mutants. Remarkably, TMV MP complemented a PSTVd mutant defective for mesophyll entry but could not support two mutants impaired for phloem entry, suggesting it fails to productively interface with plasmodesmata at the phloem boundary and that additional viral and host factors may be required. Consistent with this idea, TMV co-infection, but not the combination of MP and coat protein (CP) expression, was able to complement one of the phloem entry mutants. These observations suggest that phloem loading is a critical impediment to establishing systemic infection that could involve the entire ensemble of TMV proteins. They also demonstrate a novel strategy for analysis of MPs. Author summary: TMV 30 kDa movement protein (TMV MP) mediates virus spread in part by increasing the size exclusion limit of plasmodesmata, intercellular channels that provide cytoplasmic continuity between plant cells and regulate trafficking of protein and RNA. However, plasmodesmata connecting different cell types have unique gating mechanisms that likely contribute to the establishment of distinct cell boundaries. Thus, TMV MP may enable viral RNA passage through some but perhaps not all plasmodesmal gates. In particular, its ability to support RNA trafficking between bundle sheath cells and phloem parenchyma, a key step in phloem loading, is unknown. To address this question, available PSTVd RNA mutants defective for trafficking between specific cell types were used to infect transgenic Nicotiana benthamiana plants expressing TMV MP. TMV MP complemented a PSTVd mutant defective for invasion of underlying mesophyll following inoculation to epidermal cells. However, it failed to complement two mutants that are unable to enter the phloem, although one could be complemented by co-infection with TMV. These observations suggest that TMV MP alone does not productively interact with plasmodesmata at the phloem boundary and that additional viral and host factors are required. They further confirm that phloem loading is more complex than other types of cell-to-cell movement, and demonstrate a novel approach for the analysis of MPs. [ABSTRACT FROM AUTHOR]

This article presents the synthesis, physical properties, phytotoxicity, and SAR induction activity of 48 new ionic liquids composed of cations which are choline derivatives and anions of inducers such as salicylic acid, 2,6‐dichloroisonicotinic acid, and benzo[1.2.3]thiadiazole‐7‐carboxylic acid. The cations from which the reported salts were obtained differ in the length of the aliphatic chain bonded to the N,N‐dimethylethanolamine, N,N‐diethylethanolamine, and N,N‐dibutylethanolamine groups. Examination of the obtained series of compounds determined the correlation between the structure of the cation and the biological action of the resistance inducer and investigated the relationship between the structure of the cation and its phytotoxic effect on the plant. Systemic acquired resistance efficacy tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by tobacco mosaic virus (TMV) and phytotoxic tests were performed on Agrimonia eupatoria seeds. The results indicate that the phytotoxicity of salts composed of the same cation increases with the introduction of anions in the following order: salicylate<2,6‐dichloroisonicotinate

By means of a facile method, sixty analogs of 4‐, 6‐, and 9‐phenylphenalenone were synthesized, of which forty‐nine compounds are novel. These synthesized compounds were first evaluated for their biological activities against phytopathogenic fungi (Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae, and Physalospora piricola), tobacco mosaic virus (TMV), as well as human cancer cells (p53‐wild‐type HCT‐116 colon cancer cells, p53‐mutated HT‐29 colon cancer cells, PANC‐1 pancreatic cancer cells, and PC‐3 prostate cancer cells) systematically. 9 o was sufficiently effective against all the tested phytofungal strains and is worth further structural optimization for developing into a more potent fungicidal agent. Some effects of 6 o and 9 d (inactivation, curing, or protection) against TMV infection were more efficient than the commercial antiviral agents ribavirin and ningnanmycin. These could be selected as potential antiviral lead compounds. With regards to cytotoxicity, the cytotoxic compounds 6 p (IC50 1.6 μM in HCT‐116 cells) and 9 c (IC50 2.6 μM in PC‐3 cells) are worth further structural modification to achieve a higher antitumor potency. [ABSTRACT FROM AUTHOR]

Essential Procedural Information 3.1 Controls For a reliable test result to be obtained, the following (external) controls should be included for each series of nucleic acid extraction and amplification of the target organism and target nucleic acid, respectively Negative isolation control (NIC) to monitor contamination during nucleic acid extraction: nucleic acid extraction and subsequent amplification preferably of a sample of uninfected matrix or if not available clean extraction buffer. Essential Procedural Information 3.1 Controls For a reliable test result to be obtained, the following (external) controls should be included for each series of nucleic acid extraction and amplification of the target organism and target nucleic acid, respectively Negative isolation control (NIC) to monitor contamination during nucleic acid extraction: nucleic acid extraction and subsequent amplification preferably of a sample of uninfected matrix or if not available clean extraction buffer. Negative isolation control (NIC) to monitor contamination during nucleic acid extraction: nucleic acid extraction and subsequent amplification preferably of a sample of uninfected matrix or if not available clean extraction buffer. Essential Procedural Information 3.1 Controls For a reliable test result to be obtained, the following (external) controls should be included for each series of nucleic acid extraction and amplification of the target organism and target nucleic acid, respectively Negative isolation control (NIC) to monitor contamination during nucleic acid extraction: nucleic acid extraction and subsequent amplification preferably of a sample of uninfected matrix or if not available clean extraction buffer. [Extracted from the article]

New and detailed data are presented on the phytochemical composition of the volatile and non-volatile organic compounds of the Mediterranean endemic species Portenschlagiella ramosissima (Port.) Tutin. Both the essential oil and hydrosol were obtained from the air-dried plant by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The volatile compounds from the fresh and air-dried plants and from the hydrosol were isolated for the first time by headspace solid-phase microextraction using two fibres of different polarity. The benzene derivative group was the predominant group in all samples, with myristicin being the most abundant component of all. The non-volatile compounds of the methanol extract were analyzed by ultra-high-performance liquid chromatography–high-resolution mass spectrometry with electrospray ionisation, and three flavonoid glycosides, one anthocyanidin glycoside, and lipid derivatives were detected. Both the chemical composition and biological activities of this plant have been described in a very limited number of publications, making it an interesting source for further study. The antiphytoviral activity of the essential oil and hydrosol showed that both extracts significantly reduced the number of lesions on the leaves of local host plants infected with tobacco mosaic virus. Moderate antiproliferative activity of the methanol extract was detected in three cancer cell lines, cervical cancer cell line, human colon cancer cell line and human osteosarcoma cell line, using the MTS-based cell proliferation assay. Based on the results, we highlight this plant as a new source of bioactive compounds and natural phytotherapeutic agent that deserves further investigation. [ABSTRACT FROM AUTHOR]

Plant diseases caused by viruses and fungi have a serious impact on the quality and yield of crops, endangering food security. The use of new, green, and efficient pesticides is an important strategy to increase crop output and deal with the food crisis. Ideally, the best pesticide innovation strategy is to find and use active compounds from natural products. Here, we took the marine natural product hyrtinadine A as the lead compound, and designed, synthesized, and systematically investigated a series of its derivatives for their antiviral and antifungal activities. Compound 8a was found to have excellent antiviral activity against the tobacco mosaic virus (TMV) (inactivation inhibitory effect of 55%/500 μg/mL and 19%/100 μg/mL, curative inhibitory effect of 52%/500 μg/mL and 22%/100 μg/mL, and protection inhibitory effect of 57%/500 μg/mL and 26%/100 μg/mL) and emerged as a novel antiviral candidate. These compound derivatives displayed broad-spectrum fungicidal activities against 14 kinds of phytopathogenic fungi at 50 μg/mL and the antifungal activities of compounds 5c, 5g, 6a, and 6e against Rhizoctonia cerealis are higher than that of the commercial fungicide chlorothalonil. Therefore, this study could lay a foundation for the application of hyrtinadine A derivatives in plant protection. [ABSTRACT FROM AUTHOR]

Background and aims: One of the preventive methods used to limit the losses caused by viruses is the application of synthetic immunity inducers, such as benzo(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH). This study aimed at explaining how the BTH treatment affects the defence and developmental processes in tomato plants (Solanum lycopersicum L.) as well as plant response to virus infection. Method: The comparative multi-omics analyses concerning tomato plants treated with BTH were performed, including transcriptomics (RNA-Seq), proteomics (Liquid Chromatography-Mass Spectrometry), and metabolomics (targeted hormonal analysis). To confirm the priming effect of BTH on tomato resistance, the plants were infected with tomato mosaic virus (ToMV) seven days post-BTH treatment. Results: The combined functional analysis indicated the high impact of BTH on the plant's developmental processes and activation of the immune response early after the treatment. In the presented experimental model, the increased level of WRKY TRANSCRIPTION FACTORS, ARGONAUTE 2A, thiamine and glutathione metabolism, cell wall reorganization, and detoxification processes, as well as accumulation of three phytohormones: abscisic acid, jasmonic acid-isoleucine (JA-Ile), and indole-3-carboxylic acid (I3CA), were observed upon BTH application. Conclusion: The immune response activated by BTH was related to increased expression of genes associated with the cellular detoxification process, systemic acquired resistance, and induced systemic resistance as well as post-transcriptional gene silencing. Increased levels of I3CA and JA-Ile might explain the BTH's effectiveness in the induction of the plant defence against a broad spectrum of pathogens. For the first time, the BTH involvement in the induction of the thiamine metabolism was revealed in tomatoes. [ABSTRACT FROM AUTHOR]

We have developed methods for the templated synthesis of palladium nanowires (Pd NWs) within the central channel of tobacco mosaic virus (TMV) nanorods of various lengths. We show that uniform 4 nm diameter Pd NWs can be produced by selective growth within these channels by including the capping reagent, poly(vinyl-pyrrolidone) (PVP 30K) and reducing the metal precursor to metallic palladium with ascorbic acid. The length of the Pd NWs can be controlled either by varying the length of the nanorod templates and/or through alterations to the reaction conditions. We have also demonstrated bimetallic gold (Au)-palladium (Pd) in-situ metallization of TMV nanorods resulting in the production of Pd NWs 6 nm gold nanoparticles attached to their ends. The materials produced have many potential applications in the construction of nanoscale devices. [Display omitted] • Synthesis of 4 nm diameter palladium nanowires was achieved using TMV nanorods as a template. • Designer various length TMV nanorods specify the length of Pd nanowires. • Poly(vinyl-pyrrolidone) directs the formation of crystalline Pd nanowires. • Reaction temperature increment by 10 °C drastically increases the length of Pd nanowire. • Gold-palladium nanowires was synthesized in one step reaction. [ABSTRACT FROM AUTHOR]

Plant viruses cause systemic diseases that severely impair plant growth and development. While the accumulation of viruses in the root system has long been established, little is known as to how viruses affect root architecture. Here, we examined how the emerging tobamovirus, tomato brown rugose fruit virus (ToBRFV), alters root development in tomato. We found that ToBRFV and tobacco mosaic virus both invaded root systems during the first week of infection. ToBRFV infection of tomato plants resulted in a significant decrease in root biomass and elongation and root-to-shoot ratio and a marked suppression of root branching. Mutation in RNA-dependent RNA polymerase 6 increased the susceptibility of tomato plants to ToBRFV, resulting in severe reduction of various root growth parameters including root branching. Viral root symptoms were associated with the accumulation of auxin response factor 10a (SlARF10a) transcript, a homolog of Arabidopsis ARF10 , a known suppressor of lateral root development. Interestingly, loss-of-function mutation in SlARF10a moderated the effect of ToBRFV on root branching. In contrast, downregulation of sly-miR160a , which targets SlARF10a , was associated with constitutive suppression root branching independent of viral infection. In addition, overexpression of a microRNA-insensitive mutant of SlARF10a mimicked the effect of ToBRFV on root development, suggesting a specific role for SlARF10a in ToBRFV-mediated suppression of root branching. Taken together, our results provide new insights into the impact of tobamoviruses on root development and the role of ARF10a in the suppression of root branching in tomato. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences 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.)

Datura stramonium L. produces tropane alkaloids, and the hyoscyamine is dominant among them. Hyoscyamine is produced by hairy root cultures in vitro derived from native plants or plants with the genetically modified biosynthetic pathway for hyoscyamine. A common procedure is extraction from cultivated plants. Elicitors for increased production can be used in both cases. Live viruses are not well known for use as elicitors, therefore, D. stramonium plants grown in soil were artificially infected with the tobamoviruses Pepper mild mottle virus (PMMoV), Tomato mosaic virus (ToMV), and Tobacco mosaic virus (TMV). Differences in the content of hyoscyamine were between capsules and roots of infected and non-infected plants. Elicitation increased content of hyoscyamine in capsules 1.23–2.34 times, compared to the control. The most effective viruses were PMMoV and ToMV (isolate PV143), which increased content to above 19 mg/g of fresh weight of a capsule. The effect of each virus elicitor was expressed also in hyoscyamine content in roots. Elicited plants contained 5.41–16.54 times more hyoscyamine in roots compared to non-elicited plants. The most effective elicitor was ToMV SL-1, which raised production above 20 mg/g fresh weight of roots. It has been shown that tobamoviruses can be used as biotic elicitors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Plant virus diseases are difficult to prevent and control, causing serious economic losses to the agricultural production world. To develop new pesticides with antiviral activity, a serial of compounds containing the structure of pyrimidine and moroxydine were synthesized, among which GLY‐15 exhibited good antiviral activity against tobacco mosaic virus (TMV), while the mechanism of antiviral activity remains to be clarified. RESULTS: GLY‐15 treatment significantly inhibited the formation of necrotic spots caused by TMV in Nicotiana glutinosa, and effectively suppressed the systemic transportation of TMV expressing a reporter gene (p35S‐30B:GFP) in N. benthamiana and markedly reduced the accumulation of a movement deficient TMV in plants as well as viral RNA accumulation in tobacco protoplasts. The results of RNA sequencing showed that GLY‐15 induced significant differential expression of genes or pathways involved in the stress response, defense response and signal transduction, phytohormone response and metabolism. Among them, real‐time quantitative PCR validated that the expression of 12 critical genes such as heat shock protein, receptor kinase, cell‐wall‐related protein, disease‐related protein and glucan endo‐1,3‐β‐glucosidase were significantly up‐regulated. In addition, GLY‐15 triggered reactive oxygen species (ROS) production and induced the activity of several crucial defense related enzymes in plants. The results of molecular docking showed potential binding ability of GLY‐15 with TMV helicase and the coat protein. CONCLUSION: This study provide valuable insights into antiviral mechanism of action for GLY‐15, which is expected to be applied as a pesticide for the management of plant viruses. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus is the etiological agent of one of the most critical diseases limiting chili pepper production. Various practices have been used to manage the disease, e.g., the use of resistant varieties and interference with the vector through chemical control. However, these practices are not helpful once the virus has been established in the plant. There is still no effective method for the sustainable management of the disease; therefore, exploring new options is required. Currently, some studies have reported the activity of TiO2 NPs against viruses in plants, although not against TMV in chili pepper. The present work aims to determine a possible direct action of TiO2 NPs against TMV and if there is a relationship between the amount of virus and symptoms. The application of TiO2 NPs at 150 μg/mL in infected pepper plants reduced symptoms and viral load and improved the morphological characteristics compared to the control. Incubation of 150 µg/mL TiO2 NPs with the virus for 6 and 8 h before infection decreased viral concentration significantly after infection compared to the control. In this work, it is reported, for the first time, that the use of TiO2 NPs is a novel practice for the control of TMV in chili pepper. [ABSTRACT FROM AUTHOR]

The Polish germplasm collection of Nicotiana tabacum was started in the 1920s. Up to now, more than eight hundred accessions originating from different regions of the world have been gathered in the collection. It includes valuable breeding lines and obsolete cultivars, among them cytoplasmic male-sterile lines. Numerous cultivars are rich sources of features desired in tobacco breeding. Therefore, the accessions are continually characterised in terms of their various features, one of the most important of which is disease resistance. Much research is being done to explain the nature of resistance and its genetic basis. Moreover, cultivars with good agronomic characteristics are used in wide hybridisation, being recipients of resistance genes from wild species or are genetically modified with transgenes conditioning resistance. The biological diversity of cultivars also allows a proper selection of plant material for pathogen studies, while the large number of the accessions facilitates research into the conditions for long seed storage. Numerous examples of the use of Polish tobacco germplasm in research and breeding, specifically in disease resistance, have been presented in this paper. [ABSTRACT FROM AUTHOR]

The self-assembly of the tobacco mosaic virus coat protein is significantly altered in alcohol–water mixtures. Alcohol cosolvents stabilize the disk aggregate and prevent the formation of helical rods at low pH. A high alcohol content favours stacked disk assemblies and large rafts, while a low alcohol concentration favours individual disks and short stacks. These effects appear to be caused by the hydrophobicity of the alcohol additive, with isopropyl alcohol having the strongest effect and methanol the weakest. We discuss several effects that may contribute to preventing the protein–protein interactions between disks that are necessary to form helical rods.

Tobacco mosaic virus (TMV) is a significant viral pathogen that infects various economically important crops, including tobacco, tomatoes, and cucumbers. The current study aimed to develop and optimize essential oil-loaded nanoemulsions using Response Surface Methodology (RSM) to enhance antiviral activity against TMV in Nicotiana tabacum plants. Essential oils from tea tree (Melaleuca alternifolia) and lime peel (Citrus latifolia) were chemically analyzed using gas chromatography-mass spectrometry (GC-MS). Terpinene-4-ol (70.92 %) and trans-isolimonene (33.82 %) were identified as the major components in tea tree and lime peel oils, respectively. RSM was used to optimize the nanoemulsion formulations based on oil concentration, hydrophilic-lipophilic balance (HLB), and stirring speed. Optimal tea tree oil (TTEO) and lime peel oil (LPEO) nanoemulsions were developed and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and particle size analysis. The antiviral efficacy of the optimized formulations was tested against TMV using RT-qPCR analysis and physiological measurements. TTEO nanoemulsions significantly inhibited TMV expression by 89.78 %, while LPEO nanoemulsions achieved a 42.22 % reduction after six days. Additionally, these essential oils (EOs) enhanced plant defense mechanisms by modulating the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD), along with maintaining chlorophyll levels. This study demonstrates that TTEO and LPEO nanoemulsions offer promising eco-friendly antiviral agents for TMV management in tobacco plants. The research underscores the potential of essential oil-based formulations in mitigating viral infections in crops, providing a sustainable alternative to synthetic chemicals. [Display omitted] • The successful development and optimization of tea tree and lime peel essential oil nanoemulsions. • A significant inhibition of TMV expression by 89.78 % with tea tree oil nanoemulsions. • The enhancement of plant defense mechanisms and maintenance of chlorophyll levels, indicating a broader impact on plant health. [ABSTRACT FROM AUTHOR]

Plant proteins have been attracting increasing attention due to their significant antiviral activity against tobacco mosaic virus (TMV). This paper aimed to investigate the tobacco endogenous protein and the anti-TMV effects. Firstly, the extraction of protein from discarded tobacco leaves (DTLP) was optimized by response surface methodology (RSM). The maximum DTLP yield reached to 8.32 % under the condition of solid-liquid ratio 1:19, temperature 60 °C and pH 12. DTLP was rich in hydrophilic amino acids, such as aspartic acid (8.08 ± 0.34 g/100 g) and glutamic acid (8.02 ± 0.42 g/100 g). DTLP structure was compact and stable with a denaturation temperature of 99.7 °C. Furthermore, the anti-TMV experiments revealed that DTLP showed inactive and protective activities against TMV with inhibitory rates (79.2 % and 75.4 %, respectively) at 500 µg/mL, and inhibited the polymerization of TMV-CP to damage TMV particles. In addition, DTLP increased the expressions of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and phenylalanine ammonia lyase (PAL) in tobacco leaves by 1.55, 1.18, 9.13 and 2.92 times, respectively. Transcriptomics further verified that DTLP increased the expressions of TGA, WRKY, and PR1 genes for up-regulating the salicylic acid (SA) and pathogenesis-related proteins (PRs), thereby improving the system resistance of tobacco plants. Therefore, DTLP could be potentially developed as an alternative drug to treat plant viral diseases due to its broad-spectrum anti-TMV activity. [Display omitted] • Extractionof discarded tobacco leaves protein (DTLP) was optimized using response surface methodology. • DTLP had good thermal stability and strong hydrophilicity. • DTLP had significant activity against tobacco mosaic virus (TMV). • The anti-TMV mechanism of DTLP was to induce SAR via stimulating the expressions of TGA , WRKY , and PR1. • DTLP had the potential to be as a botanical-derived antiviral pesticide. [ABSTRACT FROM AUTHOR]

• With the development of a novel nanosystem, TDN-siR099@CPP@PDA-MS, this study is the first to deliver small compounds to plant by "spraying" method, so we would like to publicly present our results, and we believe that this technology broadens the application of RNA silencing (and other compounds) in plant disease management. • Attached, please carefully evaluate our scheme figure as below. • In the past, my research group published a highly cited paper in Cell Host&Microbe on the incorporation of host metabolizing enzymes (GAPDH) into the viral replicase complex by TBSV, a plus-strained RNA virus. Through in-depth mechanistic studies, we found that TBSV co-opts the RNA binding function of a metabolic protein, helping covert the host cell into a viral factory. • Similarly, the development of a nano-deliver system in a "spraying" approach for plant disease management in this study should be another sign of a new strategy for plant antiviral control (large area in the field). At the present time, the control of plant viral diseases is primarily achieved through the use of traditional pesticides. However, the tendency of RNA viruses to mutate and develop resistance to pesticides represents a significant challenge. The development of nanoscale strategies based on RNA interference (RNAi) represents a rapidly evolving approach to sustainable plant disease control. In this study, an siRNA was screened that effectively targets the 70-kDa heat shock protein (HSP70), which is closely associated with plant virus infection and replication. Additionally, a novel nanosystem for hierarchical delivery of siRNA was developed. This consisted of the cellular shuttle peptide (CPP)-modified tetrahedral DNA nanoparticles (TDN) as the core and polydopamine-hybridized mesoporous silica nanoparticles (PDA-MSN) as the shell. This was named TDN-siR099@CPP@PDA-MSNs. The results demonstrated that upon entering the leaf tissue through the stomata, TDN-siR099@CPP@PDA-MSNs encountered a weak acidic environment, prompting the PDA-MSN to release TDN-siR099@CPP. This resulted in the intercellular shuttling of TDN-siR099@CPP. The nanoscale dimensions of TDN-siR099@CPP facilitate facile displacement, while the intrinsic properties of CPP enhance the efficacy of long-distance siR099 intercellular shuttling. In this nanosystem, we also demonstrated that PDA-MSN retarded the susceptible degradation of siRNA in vitro and responded to the acidic release of the drug, which improve the utilization efficiency of siRNA in terms of both improving the delivery efficiency and delaying the degradation. It effectively down-regulated 56.2% of HSP70 protein and inhibited the infection of tobacco mosaic virus (TMV) and potato Y virus (PVY) by 70.2% and 41.0%, respectively. By skillfully constructing a framework for siRNA inhibition of target genes, this technology broadens the application of RNA silencing in plant disease management. [ABSTRACT FROM AUTHOR]

[Display omitted] • Arecoline derivatives were designed, synthesized and evaluated bio-activities. • Compounds 4 h and 4p with excellent activities emerged as new antiviral candidates. • These compounds can cause virus fragmentation by acting on the viral coat protein. • The work lays theoretical foundation for application of arecoline as antiviral agent. Pesticides play an important role in the development of agriculture, as they can prevent and control crop diseases and pests, improve crop yield and quality. However, the abuse and improper use of pesticides can lead to negative impacts such as environmental pollution and pest resistance issues. There is an urgent need to develop green, safe, and efficient pesticides. In this work, natural product arecoline was selected as parent structure, a series of arecoline derivatives were designed, synthesized, and systematically investigated antiviral activities against tobacco mosaic virus (TMV). These compounds were found to have good to excellent anti-TMV activities for the first time. The antiviral activities of 4a , 4 h , 4 l , 4p , 6a , 6c , and 6f are higher than that of ningnanmycin. Compounds 4 h (EC 50 value 146 µg/mL) and 4p (EC 50 value 161 µg/mL) with simple structures and excellent activities emerged as new antiviral candidates. We chose 4 h to further investigate the antiviral mechanism, which revealed that it can cause virus fragmentation by acting on the viral coat protein (CP). We further validated this result through molecular docking. These compounds also displayed broad-spectrum fungicidal activities against 8 plant pathogenic fungi. This work lays the theoretical foundation for the application of arecoline derivatives in the agricultural field. [ABSTRACT FROM AUTHOR]

• 28 aromatic acyl hydrazono dithiocarbonates with novel open-chain diester structure were synthesized by simple methods. • 12 of the new compounds contained an oxadiazole or a thiadiazole bioactive group. • The crystal structures of 4 products have been fully demonstrated by X-ray single crystal diffraction. • The antiviral and antifungal activities of products have also been tested sufficiently, and some showed good activity against tested microbes. Aromatic acyl hydrazono dithiocarbonates are generally biologically active compounds and have a high value of application in crop disease control. In this study, twenty-eight novel dialkyl dithiocarbonates were designed and synthesized, and their molecular structures were determined by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). Four compounds were characterized by X-ray single crystal diffraction as representatives. The bioassay results showed that compound 22 (diethyl dithiocarbonate with a 4-pyridyl and oxadiazole group) and 28 (dibenzyl dithiocarbonate with a p -methoxyphenyl and thiadiazole group) exhibited higher antifungal activities against Magnaporthe grisea and Cercospora arachidicola respectively compared to the control compound Chlorothalonil, while compound 21 (dimethyl dithiocarbonate with a 4-pyridyl and oxadiazole group) and 22 displayed comparable antiviral activities against tobacco mosaic virus (TMV) to the control compound Ribavirin. Structure-activity relationship analysis demonstrated that diethyl thioesters or compounds containing a 4-pyridyl group were more likely to exhibit higher inhibition effects on viruses and fungi, while the introduction of an oxadiazole moiety could contribute to the antiviral activity. Twenty-eight aromatic acyl hydrazono dithiocarbonates were synthesized from arylhydrazides, with 12 of them included oxadiazole or thiadiazole units, and the single crystal structures were characterized. In some cases, compound 22 exhibited higher antiviral activity than Ribavirin, while 22 and 28 showed higher antifungal activity than Chlorothalonil. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, 25 exopolysaccharides produced by lactic acid bacteria (LAB) were screened for their effect on plant pathogens. The molecular masses of EPS were found to be 3,8-5,0 × 104 Da. The GC–MS analysis revealed that EPSs were majorly composed of glucose (85.85–97.98 %). The FT-IR spectra of EPSs were in agreement with the typical absorption peaks of polysaccharides. EPSs showed a hydroxyl radical scavenging ability. The scavenging rate of EPS ranged from 20 to 50 % at a concentration of 5.0 mg/mL. Significant growth delay of phytopathogenic bacteria was observed after 3–6 h of cultivation. Optical density values of indicator cultures growing in the medium with EPS (1 mg/mL) were lower compared to the control by 24–100 % for Pseudomonas fluorescens , 9–46 % for P. syringae , 47–79 % for Pectobacterium carotovorum , 14–90 % for Clavibacter michiganensis , 9–100 % for Xantomonas campestris , and 45–100 % for X. vesicatorium. EPS retained their inhibitory effect on the growth of X. campestris, X. vesicatorium and C. michiganensis strains after 24–48 h of cultivation, but stimulating effect on the growth of some strains also was observed. LAB EPS showed antibiofilm activity against P. carotovorum, P. syringae , and P. fluorescent , decreasing their biofilm formation by 16–50 %, 14–39 %, and 29–59 %, respectively. Also, stimulation of biofilm formation by X. campestris (by 8–29 %) , X. vesicatorium (by 3–32 %) and C. michiganensis (by 31–41 %) strains was observed. EPSs showed antiviral activity against tobacco mosaic virus (TMV). At a concentration of 100 μg/mL, they decreased the infective ability of TMV by 61–92 %. This is the first study demonstrating that LAB EPS exhibited in vitro antibacterial and antibiofilm activity against phytopathogenic bacteria and anti-viral activity against TMV. Thus, LAB EPSs could have great potential for plant protection strategies. [ABSTRACT FROM AUTHOR]