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Cucumber mosaic virus (CMV) is non-persistently transmitted by aphids, rendering chemical insecticides ineffective. The effects of various plant extracts (neem leaf extract, garlic bulb extract, mahogany bark extract) and cultural practices (aluminium foil as reflective mulch, coriander as intercrop, marigold as border crop) on CMV incidence and severity were evaluated in capsicum at Sher-e-Bangla Agricultural University, Bangladesh. Mosaic, shoestring, vein banding and stunted growth were observed visually in the field and DAS-ELISA confirmed CMV infection in capsicum. Neem leaf extract resulted in the lowest CMV incidence (8.33%) and severity (21.67%), number of symptomatic leaves and the smallest percentage of leaf area reduction (%LAR) whereas the highest CMV incidence and severity, number of symptomatic leaves, and %LAR were observed in the untreated plots. However, the highest growth and yield parameters were recorded using aluminium foil as reflective mulch. Maximum plant height and the highest number of asymptomatic leaves were observed in aluminium foil as reflective mulch-treated plants. The highest fruit number per plant (13.33), heaviest fruits (62.10 g), highest fruit yield per plant (725.74 g), highest plot yield (2.78 kg), highest total yield (5.56 ton/ha) and lowest yield loss (17.68%) were observed in aluminium foil as reflective mulch. Neem leaf extract effectively decreased the number of aphids per leaf. Total yield negatively correlated to CMV incidence and severity with 74.2% and 95.7% yield reduction respectively, indicating that effective management of CMV will lead to higher yield. [ABSTRACT FROM AUTHOR]

To clarify the main species and infection types of tobacco viral diseases in Anshun tobacco growing areas of Guizhou Province, 306 diseased samples with symptoms such as mosaic, necrotic veins, abnormal shapes, lightning spots, and yellow spots were collected from Anshun tobacco growing areas in 2023. RT-PCR was performed using specific primers for 5 major viral diseases of tobacco mosaic virus (TMV), cucumber mosaic virus (CMV), potato Y virus (PVY), tobacco vein banding mosaic virus (TVBMV) and chilli veinal mottle virus (ChiVMV), and the detection rates of the viruses were calculated and the mixed infection types were analyzed. The results showed that the total detection rate of the viral diseases was 89.87%, and among all the diseases, TMV (81.70%)ranked the highest, followed by ChiVMV (67.97%), and CMV ranked the lowest (16.34%). The main type of infection was mixed infection with a detection rate of 68.30% . Among them, ChiVMV + TMV was the main type with a detection rate of 22.88%, followed by ChiVMV+TMV+TVBMV, ChiVMV+TMV+PVY, and ChiVMV+ TMV+CMV with detection rates of 11.11%, 10.46%, and 9.15%, respectively. TMV and ChiVMV were the dominant viral species of the tobacco viral diseases from the area, mixed infection occurred frequently and ChiVMV+TMV was the main mixed type. [ABSTRACT FROM AUTHOR]

Abstract Water dropwort (Oenanthe javanica (Blume) DC), an aquatic perennial plant from the Apiaceae family, rich in dietary fibert, vitamins, and minerals. It usually grows in wet soils and water. Despite accumulating the transcriptomic data, gene function research on water dropwort is still far behind than that of the other crops. The cucumber mosaic virus (CMV) induced gene silencing was established to study the functions of gene and microRNA (miRNA) in the water dropwort. CMV Fast New York strain (CMV-Fny) genomic RNAs 1, 2, and 3 were individually cloned into pCB301 vectors. We deleted part of the ORF 2b region and introduced recognition sites. A CMV-induced gene silencing vector was employed to suppress the expression of endogenous genes, including phytoene desaturase (PDS). In order to assess the efficacy of gene silencing, we also cloned conserved sequence of gibberellin insensitive dwarf (GID1) cDNA sequences into the vector and inoculated the water dropwort. The height of CMV-GID1-infected plants was marginally reduced as a result of GID1 gene silencing, and their leaves were noticeably longer and thinner. Additionally, we also used a CMV-induced silencing vector to analyze the roles of endogenous miRNAs. We used a short tandem target mimic approach to clone miR319 and miR396 from water dropwort into the CMV vector. Plants with CMV-miRNA infection were driven to exhibit the distinctive phenotypes. We anticipate that functional genomic research on water dropwort will be facilitated by the CMV-induced gene silencing technique.

Copyright of Academic Journal of Agriculture / Akademik Ziraat Dergisi is the property of University of Ordu, Faculty of Agriculture, Academic Journal of 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.)

In 2020, the leaves and fruit of 50 pumpkin plants with suspected cucumber mosaic virus (CMV) symptoms of leaf mosaic, vein yellowing, and mild leaf curling were collected from Sharq El-Owainat (Al Wadi El-Gaded governorate), a new reclamation land in Egypt. This study was aimed at deciphering and characterizing the causal agent of the leaf yellowing disease associated with pumpkin plants in Egypt. The causal agent was identified by serological, cytological, and molecular means. The serological identification by DAS–ELISA confirmed the presence of CMV in 20% of the plants. The cytological identification by electron microscopy revealed typical cucumovirus isometric particles of 28–30 nm diameter in the cytoplasm of the leaf parenchyma, epidermal cells, the integument, and the nucleus. Molecular characterization by one-step reverse transcriptase-PCR yielded the required size of amplicon (678 bp) for CMV. Additionally, mechanical sap inoculation was used to determine the host range and symptomatology of the isolated CMV in seventeen different plant species belonging to six different plant families. CMV replicated, moved systemically, and induced a range of symptoms in sixteen plant species. The isolated CMV was transmitted to pumpkin plants at a 16.4% rate by seeds. CMV-infected pumpkin plant leaves were characterized by a substantially low concentration of photosynthetic pigments, a high level of reducing sugars, relatively low protein levels, and a significant increase in total phenol contents, implying their potential role as antiviral agents. Ultrathin sections of infected cells revealed histological changes and cytological abnormalities in comparison to healthy plants. This is the first identification of CMV on new reclamation land in Egypt, pinpointing its swift spread, which could pose a major constraint to pumpkin production in Egypt. [ABSTRACT FROM AUTHOR]

Viral diseases of Lanzhou lilies have resulted in significant reductions in both yield and quality, particularly concerning lily symptomless virus (LSV) and cucumber mosaic virus (CMV) coinfections. However, a significant gap remains in our understanding of the mechanisms. We found coinfections had a more substantial effect on growth and nutrition compared to single infections. Metabolomics analysis showed that coinfections influenced tyrosine metabolism while increasing the accumulation of flavonoids, glycosides, etc; LSV affected carbohydrate metabolism and increased the accumulation of steroids, terpenoids, etc; CMV affected fatty acid and tryptophan metabolism, causing alterations in unsaturated fatty acids, alkaloids, and other metabolite levels. Moreover, functional metabolites significantly correlated with economic traits (i.e., growth and nutrition parameters). Additionally, the correlation is verified by multiple linear regression. This is the first report on the regulatory influence of LSV and CMV infections on lily metabolic processes and quality attributes, with the aim to provide a reference for cultivating high-quality and high-yield lily varieties. • Coinfections seriously impact lily growth and nutrition more than single infections. • Coinfections enhance tyrosine-related substances levels and tyrosine metabolism. • Coinfections increase lily antioxidant levels (i.e., flavonoids, glycosides, etc.). • Functional metabolites significantly correlate with growth and nutrition parameters. [ABSTRACT FROM AUTHOR]

Due to the impaired antiviral RNAi, the dcl2dcl4 (dcl2/4) mutant is highly susceptible to viruses deficient of the viral suppressor of the RNA silencing (VSR) contrast to wild-type Arabidopsis. It was found that more severe disease symptoms were induced in dcl2/4 infected with VSR-deficient CMV (CMV-Δ2b or CMV-2aTΔ2b) compared to wild-type Arabidopsis infected with intact CMV. In order to investigate the underlying mechanism, comparative transcriptome analysis was performed with Col-0 and dcl2/4 that were infected by CMV, CMV-Δ2b and CMV-2aTΔ2b, respectively. Our analysis showed that the systematic infection of CMV, CMV-Δ2b and CMV-2aTΔ2b could cause hypoxia response and reduce photosynthesis. Asymptomatic infections of CMV-Δ2b or CMV-2aTΔ2b in Columbia (Col-0) promoted the expression of cell division-related genes and suppressed the transcription of metabolism and acquired resistance genes. On the other hand, immunity and resistance genes were highly induced, but photosynthesis and polysaccharide metabolism-related genes were suppressed in diseased plants. More interestingly, cell wall reorganization was specifically caused in modestly diseased Col-0 infected by CMV and a strong activation of SA signaling were correspondingly induced in severely diseased dcl2/4 by CMV or CMV mutants. Thus, our research revealed the nature of the Arabidopsis–CMV interaction at the transcriptome level and could provide new clues in symptom development and antiviral defense in plants. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV), the most prevalent virus in chili pepper (Capsicum annuum L.), negatively affects chili pepper production in South Korea. In this study, foliar spraying with β-glucans obtained from the mycelial walls of the yeast-like fungus Aureobasidium pullulans inhibited CMV infection of chili pepper if applied before virus inoculation. At three concentrations, β-glucans from A. pullulans significantly ameliorated CMV symptoms in treated chili pepper; the effect was greater in plants treated with 0.01% β-glucans than 0.005% or 0.001% β-glucans. Double antibody sandwich enzyme-linked immunosorbent assay showed that these β-glucans treatments resulted in 1.7- to 10-fold reductions in CMV accumulation in the treated chili pepper. The glucans did not act directly on the virus and did not interfere with virus disassembly or replication. Foliar spraying with 0.01% β-glucans from A. pullulans at 24 hr intervals for 3 days significantly increased plant height, the total number of fruit, and the fresh weight of chili pepper fruit. However, the stem diameter of chili pepper treated with β-glucans did not increase significantly. These results indicate that foliar spraying with β-glucans from A. pullulans acts an antiviral agent against CMV infection and stimulates chili pepper growth.

A cucumber mosaic virus isolate, named Ho [CMV(Ho)], was isolated from a symptomless Arabidopsis halleri field sample containing low virus titers. An analysis of CMV(Ho) RNA molecules indicated that the virus isolate, besides the usual cucumovirus tripartite RNA genome, additionally contained defective RNA3 molecules and a satellite RNA. To study the underlying mechanism of the persistent CMV(Ho) infection in perennial A. halleri , infectious cDNA clones were generated for all its genetic elements. CMV, which consists of synthetic transcripts from the infectious tripartite RNA genomes, and designated CMV(Ho)tr, multiplied in A. halleri and annual Arabidopsis thaliana Col-0 to a similar level as the virulent strain CMV(Y), but did not induce any symptoms in them. The response of Col-0 to a series of reassortant CMVs between CMV(Ho)tr and CMV(Y) suggested that the establishment of an asymptomatic phenotype of CMV(Ho) infection was due to the 2b gene of CMV RNA2, but not due to the presence of the defective RNA3 and satellite RNA. The accumulation of CMV(Ho) 2b protein tagged with the FLAG epitope (2b.Ho-FLAG) in 2b.Ho-FLAG -transformed Col-0 did not induce any symptoms, suggesting a 2b-dependent persistency of CMV(Ho)tr infection in Arabidopsis. The 2b protein interacted with Argonaute 4, which is known to regulate the cytosine methylation levels of host genomic DNA. Whole genomic bisulfite sequencing analysis of CMV(Ho)tr- and mock-inoculated Col-0 revealed that cytosine hypomethylation in the promoter regions of 82 genes, including two genes encoding transcriptional regulators (DOF1.7 and CBP1), was induced in response to CMV(Ho)tr infection. Moreover, the increased levels of hypomethylation in the promoter region of both genes, during CMV(Ho)tr infection, were correlated with the up- or down-regulation of their expression. Taken altogether, the results indicate that during persistent CMV(Ho) infection in Arabidopsis , host gene expression may be epigenetically modulated resulting from a 2b-mediated cytosine hypomethylation of host genomic DNA. [ABSTRACT FROM AUTHOR]

A cucumber mosaic virus isolate, named Ho [CMV(Ho)], was isolated from a symptomless Arabidopsis halleri field sample containing low virus titers. An analysis of CMV(Ho) RNA molecules indicated that the virus isolate, besides the usual cucumovirus tripartite RNA genome, additionally contained defective RNA3 molecules and a satellite RNA. To study the underlying mechanism of the persistent CMV(Ho) infection in perennial A. halleri, infectious cDNA clones were generated for all its genetic elements. CMV, which consists of synthetic transcripts from the infectious tripartite RNA genomes, and designated CMV(Ho)tr, multiplied in A. halleri and annual Arabidopsis thaliana Col-0 to a similar level as the virulent strain CMV(Y), but did not induce any symptoms in them. The response of Col-0 to a series of reassortant CMVs between CMV(Ho)tr and CMV(Y) suggested that the establishment of an asymptomatic phenotype of CMV(Ho) infection was due to the 2b gene of CMV RNA2, but not due to the presence of the defective RNA3 and satellite RNA. The accumulation of CMV(Ho) 2b protein tagged with the FLAG epitope (2b.Ho-FLAG) in 2b.Ho-FLAG-transformed Col-0 did not induce any symptoms, suggesting a 2b-dependent persistency of CMV(Ho)tr infection in Arabidopsis. The 2b protein interacted with Argonaute 4, which is known to regulate the cytosine methylation levels of host genomic DNA. Whole genomic bisulfite sequencing analysis of CMV(Ho)tr- and mock-inoculated Col-0 revealed that cytosine hypomethylation in the promoter regions of 82 genes, including two genes encoding transcriptional regulators (DOF1.7 and CBP1), was induced in response to CMV(Ho)tr infection. Moreover, the increased levels of hypomethylation in the promoter region of both genes, during CMV(Ho)tr infection, were correlated with the up- or down-regulation of their expression. Taken altogether, the results indicate that during persistent CMV(Ho) infection in Arabidopsis, host gene expression may be epigenetically modulated resulting from a 2b-mediated cytosine hypomethylation of host genomic DNA.

Copyright of Ege Üniversitesi Ziraat Fakültesi Dergisi is the property of Ege Universitesi, Ziraat Fakultesi 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 most efficient method to control the plant virus diseases is breeding resistant cultivars. However, the resistance could be broken down after using resistant cultivars. This study was aimed to determine the prevalence and also serological and molecular characterization of Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) that cause infections, especially, in resistant pepper cultivars. For this reason, samples were collected from pepper growing greenhouses and open fields during vegetation period of 2015 in different parts of Antalya province including Kumluca, Demre, Serik and Aksu districts. Out of 148 pepper samples collected, 53 (35.81%) were infected with TSWV and 11 (7.34%) with CMV as a result of Double-Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DASELISA) test. Some regions on S RNA (nucleocapsid protein gene), M RNA (glycoprotein gene) and L RNA (RNAdependent RNA polymerase gene) of TSWV genome; RNA 1 (helicase/methyltransferase gene) and RNA 3 (coat proteingene) of CMV genome of DAS-ELISA positive samples were amplified by RT-PCR with specific primers. Nucleotide similarity rates of nucleocapsid protein gene, glycoprotein gene and RNA-dependent RNA polymerase gene regions of TSWV isolate varied between 92-98% identity with other isolates in GenBank and CMV isolate varied between 89-96%. TSWV isolate showed nucleotide identity varied between 92-97% with Tsw resistance breaking isolates from Capsicum plants in Turkey, Italy and Spain. Genetic determinant for overcoming pepper Tsw resistance is located in S segment but aminoacid substitutions responsible for TSWV breakdown remain contradictory in several reports.

Due to the impaired antiviral RNAi, the dcl2dcl4 (dcl2/4) mutant is highly susceptible to viruses deficient of the viral suppressor of the RNA silencing (VSR) contrast to wild-type Arabidopsis. It was found that more severe disease symptoms were induced in dcl2/4 infected with VSR-deficient CMV (CMV-Δ2b or CMV-2aTΔ2b) compared to wild-type Arabidopsis infected with intact CMV. In order to investigate the underlying mechanism, comparative transcriptome analysis was performed with Col-0 and dcl2/4 that were infected by CMV, CMV-Δ2b and CMV-2aTΔ2b, respectively. Our analysis showed that the systematic infection of CMV, CMV-Δ2b and CMV-2aTΔ2b could cause hypoxia response and reduce photosynthesis. Asymptomatic infections of CMV-Δ2b or CMV-2aTΔ2b in Columbia (Col-0) promoted the expression of cell division-related genes and suppressed the transcription of metabolism and acquired resistance genes. On the other hand, immunity and resistance genes were highly induced, but photosynthesis and polysaccharide metabolism-related genes were suppressed in diseased plants. More interestingly, cell wall reorganization was specifically caused in modestly diseased Col-0 infected by CMV and a strong activation of SA signaling were correspondingly induced in severely diseased dcl2/4 by CMV or CMV mutants. Thus, our research revealed the nature of the Arabidopsis–CMV interaction at the transcriptome level and could provide new clues in symptom development and antiviral defense in plants.

Cucumber mosaic virus (CMV) is polyphagous, infecting plants in several families. CMV has occurred as a minor pathogen in Allium crops in several Mediterranean countries, but little was known of the virus naturally infecting Allium spp. This study completed molecular and biological characterization of CMV-14.3Po and CMV-15.5Po, two newly identified CMV isolates infecting onion (Allium cepa L.) in Turkey. Phylogenetic, and nucleotide and amino acid sequence identity analyses of partial RNA2 and RNA3 of the two isolates showed that they were very similar to other CMV isolates from Mediterranean, European, and East Asian countries. Phylogenetic analysis of the partial sequence of RNA3 also showed that the onion isolates belong to subgroup IA. Onion isolates were mechanically transmissible, and caused mild leaf malformation on onion, severe leaf malformation and stunting on garlic (Allium sativus L.), and mosaic and mottle on cucumber (Cucumis sativus L.) and melon (Cucumis melo L.).

Luffa cylindrica L. is a cash crop which has important health, medicinal and industrial value, but no high saturation genetic map has been constructed owing to a lack of efficient markers. Furthermore, no genes were reportedly responsible for CMV resistance in Luffa spp. Specific length amplified fragment sequencing (SLAF-seq) is a valuable tool for large-scale discovery of markers and genetic mapping. The present study reported the construction of a high-density genetic map and the mapping of CMV resistant genes by using an F2 population of 130 individuals and their two inbred line parents. A total of 271.01 Mb pair-end reads were generated. 100,077 high-quality SLAFs were detected, and 7404 of them were polymorphic. Finally, 3701 of the polymorphic markers were selected for genetic map construction, and 13 linkage groups were generated. The map spanned 1518.56 cM with an average distance of 0.41 cM between adjacent markers. Based on the newly constructed high-density map, one gene located on chromosome 1 (100.072–100.457 cM) was identified to regulate CMV resistance in L. cylindrica. A gag-polypeptide of LTR copia-type retrotransposon was predicted as the candidate gene responsible for CMV resistance in L. cylindrica. The high-density genetic map and the CMV resistant gene mapped and predicted in this study will be useful in future research. [ABSTRACT FROM AUTHOR]

Although accumulating evidence indicates that tolerance is a plant defence strategy against pathogens as widespread as resistance, how plants evolve tolerance is poorly understood. Theory predicts that hosts will evolve to maximize tolerance or resistance, but not both. Remarkably, most experimental works failed in finding this trade-off. We tested the hypothesis that the evolution of tolerance to one virus is traded-off against tolerance to others, rather than against resistance and identified the associated mechanisms. To do so, we challenged eighteen Arabidopsis thaliana genotypes with Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV). We characterized plant life-history trait modifications associated with reduced effects of TuMV and CMV on plant seed production (fecundity tolerance) and life period (mortality tolerance), both measured as a norm of reaction across viral loads (range tolerance). Also, we analysed resistance-tolerance and tolerance-tolerance trade-offs. Results indicate that tolerance to TuMV is associated with changes in the length of the pre-reproductive and reproductive periods, and tolerance to CMV with resource reallocation from growth to reproduction; and that tolerance to TuMV is traded-off against tolerance to CMV in a virulence-dependent manner. Thus, this work provides novel insights on the mechanisms of plant tolerance and highlights the importance of considering the combined effect of different pathogens to understand how plant defences evolve. [ABSTRACT FROM AUTHOR]

Aphids transmit CMV (cucumber mosaic virus) in a non-persistent manner. However, little is known about the mechanism of CMV transmission. In this study, an integrated analysis of the mRNA and protein was performed to identify important putative regulators involved in the transmission of CMV by aphids. At the level of transcription, a total of 20,550 genes (≥2-fold expression difference) were identified as being differentially expressed genes (DEGs) 24 h after healthy aphid transfer to infected tobacco plants using the RNA-seq approach. At the protein level, 744 proteins were classified as being differentially abundant between virus-treated and control M. persicae using iTRAQ (isobaric tags for relative and absolute quantitation) analysis. The combined mRNA and protein analysis enabled the identification of some viral putative regulators, such as cuticle proteins, ribosomal proteins, and cytochrome P450 enzymes. The results show that most of the key putative regulators were highly accumulated at the protein level. Based on those findings, we can speculate that the process by which aphids spread CMV is mainly related to post-translational regulation rather than transcription.

The most efficient method to control the plant virus diseases is breeding resistant cultivars. However, the resistance could be broken down after using resistant cultivars. This study was aimed to determine the prevalence and also serological and molecular characterization of Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) that cause infections, especially, in resistant pepper cultivars. For this reason, samples were collected from pepper growing greenhouses and open fields during vegetation period of 2015 in different parts of Antalya province including Kumluca, Demre, Serik and Aksu districts. Out of 148 pepper samples collected, 53 (35.81%) were infected with TSWV and 11 (7.34%) with CMV as a result of Double-Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DASELISA) test. Some regions on S RNA (nucleocapsid protein gene), M RNA (glycoprotein gene) and L RNA (RNAdependent RNA polymerase gene) of TSWV genome; RNA 1 (helicase/methyltransferase gene) and RNA 3 (coat protein gene) of CMV genome of DAS-ELISA positive samples were amplified by RT-PCR with specific primers. Nucleotide similarity rates of nucleocapsid protein gene, glycoprotein gene and RNA-dependent RNA polymerase gene regions of TSWV isolate varied between 92-98% identity with other isolates in GenBank and CMV isolate varied between 89-96%. TSWV isolate showed nucleotide identity varied between 92-97% with Tsw resistance breaking isolates from Capsicum plants in Turkey, Italy and Spain. Genetic determinant for overcoming pepper Tsw resistance is located in S segment but aminoacid substitutions responsible for TSWV breakdown remain contradictory in several reports. [ABSTRACT FROM AUTHOR]

A single-chain variable antibody fragment (scFv) library tested against the non-structural NSP5 protein of human rotavirus A was screened by a yeast two-hybrid system against three proteins derived from the RNA-dependent RNA polymerase (RdRp) of cucumber mosaic virus (CMV), with the aim of blocking their function and preventing viral infection once expressed in planta. The constructs tested were (i) '2a' consisting of the full-length 2a gene (839 amino acids, aa), (ii) 'Motifs' covering the conserved RdRp motifs (IV-VII) (132 aa) and (iii) 'GDD' located within the conserved RdRp motif VI (GDD, 22 aa). In yeast two-hybrid (Y2H) selection assays the '2a' and 'Motifs' constructs interacted with 96 and 25 library constructs, respectively, while the 'GDD' construct caused transactivation. Y2H-interacting scFvs were analyzed in vivo for their interaction with the 2a and Motifs proteins in a mammalian transient expression system. Eighteen tobacco lines stably transformed with four selected scFvs were produced and screened for resistance against two different CMV isolates. Different levels of resistance and rate of recovery were observed with CMV of both groups I and II, particularly in lines expressing intrabodies against the full-length 2a protein. This work describes for the first time the use of intrabodies against the RdRp of CMV to obtain plants that reduce infection of a pandemic virus, showing that the selected scFvs can modulate virus infection and induce premature recovery in tobacco plants. Image 1 • A scFv library previously screened in a Y2H system against a human rotavirus was tested against CMV 2a protein derivatives. • Positive scFvs were analyzed for their interaction with CMV 2a protein derivatives in mammalian transient expression system. • Tobacco plants transformed with four selected scFvs had reduced levels of CMV and showed premature recovery from infection. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV) can infect a wide range of host species. For the lacking of CMV resistant varieties of tomato, RNA interference (RNAi) can be used as a fast and effective method for the generation of transgenic resistant varieties. In this current study, five intron-spliced hairpin RNA (ihpRNA) plant expression vectors aimed at five genes of CMV have been constructed. Transgenic tomatoes were obtained by Agrobacterium tumefaciens-mediated transformation with expression vectors. Highly resistant generations of transgenic plants were employed as rootstocks and grafted onto non-transgenic tomatoes that resulted in the successful transfer of resistance to the scions. Using a novel method of plant cuttings for rootstock propagation, we obtained large quantities of disease-resistant material. Further, this method produces scions that can remain undetectable for transgenic resistance marker genes that may provide novel approaches to evade collective concerns about genetically-modified organism (GMO) biosafety.

Plant virus management is mostly achieved through control of insect vectors using insecticides. However, insecticides are only marginally effective for preventing virus transmission. Furthermore, it is well established that symptoms of virus infections often encourage vector visitation to infected hosts, which exacerbates secondary spread. Plant defense elicitors, phytohormone analogs that prime the plant immune system against attack, may be a viable approach for virus control that complements insecticide use by disrupting pathologies that attract vectors. To explore this, we tested the effect of a commercial plant elicitor, acibenzolar-S-methyl (ASM), on infection rates, virus titers, and symptom development in melon plants inoculated with one of two virus species, Cucumber mosaic virus (CMV) and Cucurbit yellow stunting disorder virus (CYSDV). We also conducted behavioral assays to assess the effect of ASM treatment and virus inoculation on vector behavior. For both pathogens, ASM treatment reduced symptom severity and delayed disease progression. For CYSDV, this resulted in the attenuation of symptoms that encourage vector visitation and virion uptake. We did observe slight trade-offs in growth vs. defense following ASM treatment, but these effects did not translate into reduced yields or plant performance in the field. Our results suggest that immunity priming may be a valuable tool for improving management of insect-transmitted plant viruses.

Cucumber mosaic virus possesses 2b gene known as a suppressor of post-transcriptional gene silencing (PTGS). To investigate its function and effect in plant, transgenic Nicotiana benethamiana expressing 2b gene was developed and analyzed in phenotypic characteristics and differential gene expression (DEG) comparing with wild-type. Eight lines of transgenic plants (T0) were obtained with difficulty and showed severe deformed phenotypes in leaves, flowers, petioles and etc. Moreover, transgenic plants were hardly able to set seeds, but small amounts of seeds were barely produced in some of transgene-hemizygous plants. DEG analysis showed that transgenic plant ectopically accumulated diverse RNA transcripts at higher levels than wild-type probably due to the disturbance in RNA metabolism, especially of RNA decay, caused by 2b-mediated inhibition of PTGS. These ectopic accumulations of RNAs disrupt protein and RNA homeostasis and then subsequently lead to abnormal phenotypes of transgenic plants.

Hot pepper ( Capsicum annuum L.) is becoming an increasingly important vegetable crop in the world. Cucumber mosaic virus (CMV) is a destructive virus that can cause leaf distortion and fruit lesions, affecting pepper production. However, studies on the response to CMV infection in pepper at the transcriptional level are limited. In this study, the transcript profiles of pepper leaves after CMV infection were investigated using Illumina and single-molecule real-time (SMRT) RNA-sequencing (RNA-seq). A total of 2143 differentially expressed genes (DEGs) were identified at five different stages. Gene ontology (GO) and KEGG analysis revealed that these DEGs were involved in the response to stress, defense response and plant-pathogen interaction pathways. Among these DEGs, several key genes that consistently appeared in studies of plant-pathogen interactions had increased transcript abundance after inoculation, including chitinase, pathogenesis-related (PR) protein, TMV resistance protein, WRKY transcription factor and jasmonate ZIM-domain protein. Four of these DEGs were further validated by quantitative real-time RT-PCR (qRT-PCR). Furthermore, a total of 73, 597 alternative splicing (AS) events were identified in the pepper leaves after CMV infection, distributed in 12, 615 genes. The intron retention of WRKY33 (Capana09g001251) might be involved in the regulation of CMV infection. Taken together, our study provides a transcriptome-wide insight into the molecular basis of resistance to CMV infection in pepper leaves and potential candidate genes for improving resistance cultivars. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV), a positive-sense single-stranded RNA virus, has a very wide host range and a worldwide distribution, and is considered as one of the most virulent plant viruses in the world. The CMV gene sequences, gene products, and their interaction with hosts have been extensively reported since it was discovered in 1916. With the development of high-throughput sequencing and proteomics, great progress has been made in the molecular mechanism of CMV pathogenesis in recent years. In this review, we introduce CMV-encoded proteins, CMV-related satellite RNAs and the roles of host factors in the pathogenesis of CMV, to provide a theoretical basis for future study of CMV. [ABSTRACT FROM AUTHOR]

Field surveys were conducted during 2012–14 to document the occurrence and distribution of viruses infecting cucurbits in all the seven agroclimatic zones of Tamil Nadu state, south India. Samples collected from various types of cucurbits showing virus-like symptoms were tested for Cucumber mosaic virus (CMV), Papaya ringspot virus (PRSV), Zucchini yellow mosaic virus (ZYMV), Cucumber green mottle mosaic virus (CGMMV) and begomoviruses using serological (Dot Immuno Binding Assay, DIBA) and molecular (RT-PCR for RNA viruses and PCR for DNA viruses) methods. Results indicated higher incidence (98.6%) of begomoviruses, followed by PRSV (32.1%) and CGMMV (22.2%). ZYMV and CMV were detected at a lower frequency of 7.1% and 5%, respectively. Mixed infections with two or three of these viruses were observed in more than 50% of the samples analyzed. Sequencing of begomovirus-specific amplicons indicated the presence of sequences highly similar to Tomato leaf curl New Delhi virus (ToLCNDV) and Squash leaf curl China virus (SLCCNV). [ABSTRACT FROM AUTHOR]

Cucumber Mosaic Virus (CMV) is one of pathogenic viruses that commonly found and has caused significant losses in many chrysanthemum growers in Indonesia. Efforts have been made to get healthy plant source through eliminating virus from infected plants and one of the promising methods was the combination of thermotherapy and meristem culture. The research was conducted to find out the effect of meristem culture following heat treatments on the existence of CMV in infected chrysanthemum plantlets. The experiment was carried out in the laboratory of tissue culture and virology at The Indonesian Ornamental Crops Research Institute (IOCRI) from August 2007 until June 2008. A complete factorial with ten replications was designed to accomplish the combination of two factors. The first factor was three chrysanthemum cultivars, namely Stroika, Dewi Sartika and White Fiji, while the second dealt with the durations of heat treatment i.e. one, two and three weeks. The results showed that plantlet survival decreased, yet improved plantlet performance by faster bud initiation with lengthened heat duration. The percentage of virus-free planlets also increased along with the duration of treatment and three weeks heat treatment followed by meristem culture effectively eliminated CMV from infected planlets.

The occurrence of Bean yellow mosaic virus (BYMV), Cucumber mosaic virus (CMV) Tobacco rattle virus (TRV) in gladiolus, iris, tulip and Iris yellow spot virus (IYSV) in iris was investigated by examining the plants by the means of serological techniques (ELISA). ELISA was applied to determine the presence of BYMV, CMV, TRV infections in both aerial and underground parts of gladiolus, iris, and tulip, and IYSV on the aerial parts of iris, respectively. 262 gladiolus plants were tested. 63.7% was infected by BYMV, 29.4 % by CMV, and 2.7 % by TRV. Out of 180 plants of iris, 1.1% was infected by BYMV, 6.7% by CMV, 2.8% by TRV, and 0% by IYSV. Out of 28 plants of tulip, 28.6% was infected by CMV, and 7.1% by TRV. ELISA proved to be a suitable method for detection of viruses in leaves of these ornamental plants, but it often failed to detect viruses in flowers and corms. A high transmission of BYMV by gladiolus cormlets was also found.

Background: Cucumber mosaic virus (CMV) is the most serious virus disease affecting chilli ( Capsicum annuum L.) worldwide and the absence of natural resistance makes management of CMV outbreaks difficult. The characterization of improved sources of resistance to CMV in chilli would facilitate the development of commercially acceptable chilli varieties with adequate levels of CMV resistance. A total of 30 chilli genotypes were evaluated for their reaction to CMV in field and artificial inoculated conditions during 2010-2011 and 2011-2012. Large differences were observed among genotypes for disease incidence, severity indexes, and yield losses. Based on observed data, genotype CA23 (Noakhali) was identified as resistant, while CA12 (Comilla-2) was categorized as moderately resistant to CMV both in natural and inoculated conditions. Enzyme-linked immunosorbent assay absorbance values of samples taken from CMV-infected leaves corresponded well with visible viral symptoms for these genotypes. The identified C. annuum CA23 and CA12 genotypes represent previously undescribed and potentially useful sources of CMV resistance. [ABSTRACT FROM AUTHOR]

The production of reactive oxygen species (ROS) forms part of the defense reaction of plants against invading pathogens. ROS have multifaceted signaling functions in mediating the establishment of multiple responses. To verify whether hydrogen peroxide (H2O2) contributes to plant virus infection and the development of induced symptoms, we used fluorescence to monitor the generation of H2O2 and confocal laser scanning microscopy (CLSM) to investigate the subcellular distribution of H2O2 in leaves. In this study, the M strain of Cucumber mosaic virus (M-CMV) induced heavy chlorotic symptoms in Nicotiana tabacum cv. white burley during systemic infection. Compared with mock-inoculated leaves, H2O2 accumulation in inoculated leaves increased after inoculation, then decreased after 4 days. For systemically infected leaves that showed chlorotic symptoms, H2O2 accumulation was always higher than in healthy leaves. Subcellular H2O2 localization observed using CLSM showed that H2O2 in inoculated leaves was generated mainly in the chloroplasts and cell wall, whereas in systemically infected leaves H2O2 was generated mainly in the cytosol. The levels of coat protein in inoculated and systemically infected leaves might be associated with changes in the level of H2O2 and symptom development. Further research is needed to elucidate the generation mechanism and the relationship between coat protein and oxidative stress during infection and symptom development. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Temperature is an important environmental factor controlling plant growth, development, and immune response. However, the role of temperature in plant disease resistance is still elusive. In the present study, the potential effects of temperature on the interaction between Nicotiana tabacum and Cucumber mosaic virus (CMV) were investigated. Our results indicated that N. tabacum plants displayed severe symptoms at early stage of post inoculation at high temperature (HT, 28°C), associated with higher viral replication level, more serious stress damages. By contrast, low temperature (LT, 18°C) effectively delayed the replication of CMV compared with elevated temperatures. Additionally, quantitative real-time PCR analyses revealed that lower temperatures (≤ 24°C) promote salicylic acid (SA) dependent responses, whereas higher temperatures (> 24°C) activate the genes expression of jasmonic acid (JA) pathway. Interestingly, the dark green islands (DGIs) appeared much earlier in CMV-inoculated plants grown at HT compared with those at LT and the accumulation of virus small interfering RNAs in plants were significantly up-regulated under elevated temperatures at early stage of post inoculation. Taken together, these results indicated that temperature changes had important effects on plant defence response, and different temperatures could induce different immune pathways of N. tabacum against CMV infection. [ABSTRACT FROM AUTHOR]

It has been hypothesized that plant--virus interactions vary between antagonism and conditional mutualism according to environmental conditions. This hypothesis is based on scant experimental evidence, and to test it we examined the effect of abiotic factors on the Arabidopsis thaliana--Cucumber mosaic virus (CMV) interaction. Four Arabidopsis genotypes clustering into two allometric groups were grown under six environments defined by three temperature and two light-intensity conditions. Plants were either CMV-infected or mock-inoculated, and the effects of environment and infection on temporal and resource allocation life-history traits were quantified. Life-history traits significantly differed between allometric groups over all environments, with group 1 plants tolerating abiotic stress better than those of group 2. The effect of CMV infection on host fitness (virulence) differed between genotypes, being lower in group 1 genotypes. Tolerance to abiotic stress and to infection was similarly achieved through life-history trait responses, which resulted in resource reallocation from growth to reproduction. Effects of infection varied according to plant genotype and environment from detrimental to beneficial for host fitness. These results are highly relevant and demonstrate that plant viruses can be pleiotropic parasites along the antagonism--mutualism continuum, which should be considered in analyses of the evolution of plant--virus interactions. [ABSTRACT FROM AUTHOR]

Light is an important environment factor controlling plant growth, development, and nutritional quality and is also one of the most important factors inducing plant defence. In this study, we assayed the potential effects of light quality on the interaction between Nicotiana tabacum and cucumber mosaic virus ( CMV). Our results indicated that white light-treated N. tabacum plants displayed obvious symptoms at early stage postinoculation, while the symptoms were significantly inhibited under red light and blue light. Western blotting and quantitative real-time PCR ( qRT- PCR) analyses showed that blue light and red light can effectively delay the replication of CMV compared with white light. The activities of various reactive oxygen species ( ROS)-scavenging enzymes and reducing substances [reduced glutathione ( GSH) and ascorbic acid ( ASA)] were increased under blue light and red light. In addition, hormone measurements and qRT- PCR analyses revealed that salicylic acid ( SA)-mediated signalling pathway plays positive role in the related regulation, and cytokinin ( CTK) may also participate in them. Furthermore, we found that the formation of dark green islands ( DGIs) was significantly suppressed in plants under red light and blue light at 30 days postinoculation (Dpi). However, the accumulation of virus in plants under different light conditions had no notable differences at later stage of postinoculation. Taken together, these results indicated that red light and blue light could effectively delay symptom expression and replication of CMV on N. tabacum at the relatively earlier stage postinoculation. [ABSTRACT FROM AUTHOR]

Disease development in Nicotiana tabacum after inoculation with cucumber mosaic virus (CMV) was accelerated when plants were grown in high light (300 µmol m s, HL) compared with those grown in low light (70 µmol m s, LL). Several characteristic defense reactions, including release of reactive oxygen species, accumulation of salicylic acid (SA), expression of SA-mediated pathogenesis related (PR) proteins and the systemic development of disease, were proved to be light dependent. Plants exposed to HL or medium light (150 µmol m s, ML) had serious oxidative damage caused by CMV infection compared with LL-plants. In addition, the levels of SA and mRNA transcripts for non- expressor of pathogenesis- related gene 1 in CMV-inoculated plants were the highest under LL with decreasing photon flux density. In HL-exposed plants, the expression of PR1 and PR2 were repressed, but the expression of PR5 was not significantly altered, revealing a complex cross talk between light intensity and the SA signaling pathway in regulating N. tabacum response to the infection of CMV. Taken together, our results revealed that increased light intensity reduced the resistance ability of N. tabacum to CMV, correlating with repression of the SA-dependent signaling pathway and a change in the cellular redox status in plants cells. [ABSTRACT FROM AUTHOR]

Key message: There are significant differences between the DGIs and LGTs. Additionally, most of the characteristics indicate that the DGIs are more similar to recovered tissue and can resist viral attacks. Abstract: Dark green islands (DGIs) surrounded by light green tissues (LGTs) are common leaf symptoms of plants that are systemically infected by various mosaic viruses. We performed cytological, physiological and molecular biological analyses of the DGIs and LGTs in cucumber mosaic virus-infected Nicotiana tabacum leaves. Our results indicated that the DGIs contained less virus than did the LGTs. Compared to the LGTs, the DGIs contained higher levels of the metabolites involved in plant defence. The contents of reduced glutathione and ascorbic acid were increased in the DGIs to reach levels that were even higher than those of control plants. Moreover, hormone measurements and quantitative real-time PCR analysis revealed that the endogenous salicylic acid, ethylene and defence genes mediated these elevations by playing positive roles in the regulation of the DGIs responses to viral infection. The accumulation of cytokinin was also much greater in the DGIs than in the LGTs. Finally, northern blotting analysis indicated that the accumulation of viral small interfering RNAs was decreased in the DGIs compared to the LGTs. Taken together, these results suggest that DGIs might represent leaf areas that have recovered from viral infection due to locally enhanced defence responses. [ABSTRACT FROM AUTHOR]

Enormous economic losses caused by infection of peppers with Cucumber mosaic virus (CMV) have spurred the development of CMV-resistant peppers using genetic techniques. However, growing concern from the general public over genetically modified (GM) crops has focused attention on safety and labeling issues. In this study, we developed and optimized a qualitative and quantitative enzyme-linked immunosorbent assay (ELISA) to detect CMV-resistant GM peppers. Two types of antibodies, virion-derived polyclonal antibody (VPAb) prepared from a CMV-Fny virion-immunized rabbit and peptide-based polyclonal antibody (PPAb) prepared from rabbits immunized with a peptide fragment of CMVcoat protein (CMV-CP) (LPDSVTEYDKKLVSR) predicted from the nucleotide sequence were prepared, and their affinities were compared. Optimized ELISAs using VPAb and PPAb as the primary antibodies, respectively, were carried out to measure the level of CMV-CP in GM peppers cultivated at an officially approved facility in Korea. Color development (reflecting CMV-CP levels) was 2.5-fold higher when PPAb was used as the primary antibody compared to VPAb as the primary antibody. No statistical differences were observed among GM pepper cultivars. These results imply that PPAb has higher specificity for CMV-CP than VPAb does, and that the analytical system presented in this study can be used to evaluate the level of CMV-CP in genetically modified peppers. [ABSTRACT FROM AUTHOR]

The study of the biochemical and molecular mechanisms deriving from the host-pathogen-antagonist interaction is essential to understand the dynamics of infectious processes and can be useful for the development of new strategies to control phytopathogens, particularly viruses, against which chemical treatments have no effect. In this work, we demonstrate the ability of the rhizospheric fungus Trichoderma harzianum strain T-22 (T22) to induce defense responses in tomato ( Solanum lycopersicum var. cerasiforme) against Cucumber mosaic virus (CMV, family Bromoviridae, genus Cucumovirus) strain Fny. A granule formulation containing T22 was used for treating the plants before, simultaneously or after the CMV inoculation, in order to study the molecular and biochemical aspects of the interaction between T22 and tomato against the virus. Reactive oxygen species (ROS) and the genes encoding for ROS scavenging enzymes were investigated. Histochemical analysis revealed a different increase in the superoxide anion ( $$ {\text{O}}_{2}^{ \bullet - } $$ ) and hydrogen peroxide (HO) content in plants infected by CMV alone or in the presence of T22, confirming the involvement of ROS in plant defense responses. Gene expression analysis suggested a definite improvement in oxidative stress when plants were treated with T22 after inoculation with CMV. In conclusion, our data indicate that Trichoderma harzianum T-22 stimulates the induction of tomato defense responses against CMV, an action that implies the involvement of ROS, pointing towards its use as a treatment rather than as a preventive measure. [ABSTRACT FROM AUTHOR]