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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]

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. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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.)

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]

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]

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]

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]

Key message: Soybean expressing theCucumber mosaic virus 2b gene manifests seed coat pigmentation due to suppression of endogenous RNA silencing but no other morphological abnormality. This gene may help prevent transgene silencing.RNA silencing is an important mechanism for gene regulation and antiviral defense in plants. It is also responsible for transgene silencing, however, and thus hinders the establishment of transgenic plants. The 2b protein of Cucumber mosaic virus (CMV) functions as a suppressor of RNA silencing and therefore might prove beneficial for stabilization of transgene expression. We have now generated transgenic soybean that harbors the 2b gene of a CMV-soybean strain under the control of a constitutive promoter to investigate the effects of 2b expression. No growth abnormality was apparent in 2b transgenic plants, although the seed coat was pigmented in several of the transgenic lines. Genes for chalcone synthase (CHS), a key enzyme of the flavonoid pathway, are posttranscriptionally silenced by the inhibitor ( I) locus in nonpigmented (yellow) soybean seeds. The levels of CHS mRNA and CHS small interfering RNA in strongly pigmented 2b transgenic seed coats were higher and lower, respectively, than those in the seed coat of a control transgenic line. The expression level of 2b also correlated with the extent of seed coat pigmentation. On the other hand, introduction of the 2b gene together with the DsRed2 gene into somatic embryos prevented the time-dependent decrease in transient DsRed2 expression. Our results indicate that the 2b gene alone is able to suppress RNA silencing of endogenous CHS genes regulated by the I locus, and that 2b is of potential utility for stabilization of transgene expression in soybean without detrimental effects other than seed coat pigmentation. [ABSTRACT FROM AUTHOR]

Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provide insights into novel strategies for plant defense against pathogens and plant protection against pollutants. [ABSTRACT FROM AUTHOR]

A field survey was conducted in eight local government areas (LGA) of Ogun state, Nigeria to assess the incidence of viral diseases of yams in the areas. Leaf samples were collected from 90 yam plants which were either symptomatic or asymptomatic. These were bulked into 45 during serological tests and the viruses indexed include yam mosaic virus (YMV); Dioscorea alata bacilliform virus (DaBV) and cucumber mosaic virus (CMV). DaBV was the most prevalent virus on the field with incidence of 48.9% (22/45) followed by YMV which occurred in 42.2% (19/45). CMV had the lowest percentage of incidence; 2.2% (1/45). Of all the LGAs visited, Abeokuta north and Abeokuta south had the highest incidence of YMV and DaBV, respectively. Mixed virus infections were also detected. [ABSTRACT FROM PUBLISHER]

Pollen of genetically modified (GM) pepper containing the gene for cucumber mosaic virus (CMV) coat protein (CP) and GM Chinese cabbage with high phenylethylisothiocyanate (PEITC) content was investigated for assessment of allergic risk. Amino acid (AA) sequences of the inserted gene products of GM virus resistant pepper and GM Chinese cabbage with high PEITC content were compared with those of known allergens. No known allergen greater than 35% AA sequence homology, over 80 AA window or more than 8 consecutive identical AA was found. Protein patterns of GM/non-GM pepper and Chinese cabbage pollen extracts in SDS-PAGE analysis showed the same distribution of protein bands among the GM and non-GM pepper or Chinese cabbage, respectively. Sera from pollen allergic patients showed some IgE reactivity via immunoblotting and ELISA; however, no differences were observed between the pollen of GM and non-GM pepper or Chinese cabbage, respectively. Based on these results, we conclude that pollens of the virus resistant GM pepper and GM Chinese cabbage with high PEITC have no differences in their protein composition or allergenicity relative to non-GM pepper and Chinese cabbage. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the antiphytoviral activity of bruceine-D from Brucea javanica seeds and its inhibitory activity against plant virus. An antiphytoviral compounds which was identified as bruceine-D was isolated by conventional spectroscopy method. A strong inhibitory effect on the infectivity of potato virus Y and cucumber mosaic virus was observed. The study shows that the compound could effectively inhibit systemic tobacco mosaic virus infection in the host tobacco plant under glasshouse condition. The study concludes that bruceine-D from Brucea javanica may have the potential to be used as a natural viricide or a lead compound for new viricides.

A survey of mosaic diseases in fields of open air grown melon was done in three provinces of Spain over 3 years. The incidence of the mosaic-inducing viruses Cucumber mosaic virus (CMV), Watermelon mosaic virus-2 (WMV-2), Papaya ringspot virus watermelon strain (PRSV-W) and Zucchini yellow mosaic virus (ZYMV) was assessed. The only viruses present in the three provinces during the 3 years studied were CMV and WMV-2, but their incidence differed according to year and region. For each epidemic, disease progress curves (DPC) were obtained, all of them well described by the Gompertz model. With the five descriptive variables of the model, a principal component analysis was done and two principal components, representing a severity factor and a time factor were found. Cluster analyses done with these two principal components, grouped the epidemics into 6 clusters that did not correlate with year, virus or province. Correlation analyses between epidemics caused by WMV-2 and CMV and climatic variables were done. Although the temperature in the spring months was the main factor associated with the severity of the epidemics caused by these two viruses, other differential correlations were found. Spatial evolution of CMV and WMV-2 epidemics was also different suggesting different aphid species acting as vectors for the viruses. [ABSTRACT FROM AUTHOR]

Partial restriction of cucumber mosaic virus (CMV) long-distance movement originating from the Capsicum annuum inbred line ’Vania’ was assessed in a doubled-haploid progeny using two screening methods: the first allowed one to assess the resistance of adult plants decapitated above the fourth leaf and inoculated on the third leaf using a common CMV strain, and the second allowed one to assess CMV resistance to long-distance movement on seedlings inoculated using an atypical CMV strain. For both resistance tests, the behavior of the F1 hybrid between ’Vania’ and the susceptible line ’H3’ indicated that partial resistance is inherited as a dominant trait. Phenotypic data from the two screening methods were correlated but the one performed on seedlings was much more severe. A subset of 184 molecular markers well-distributed over the pepper genome was selected for QTL mapping using the composite interval mapping (CIM) method. A total of seven genomic regions, including one major effect and several minor effect QTLs, were shown to be associated with partial restriction of CMV long-distance movement. These results are compared with those already obtained in pepper and also in other solanaceous crops, potato and tomato. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV) and bean yellow mosaic virus are the most prevalent viruses in gladiolus fields in Israel. Factors affecting infection were studied, as a basis for the buildup of virus-tested propagation material. Marked differences in the susceptibility of gladiolus cultivars to aphid-borne infection were observed, both in field experiments and in test aphid inoculations. Cultivars 'Euro-vision' and 'Trader Horn' were resistant, while 'Peter Pears' and 'Commando' were highly susceptible. The aphid that landed most frequently on gladiolus was Macrosiphum euphorbiae. In test inoculations M. euphorbiae and Aphis gossypii efficiently transmitted CMV from gladiolus to gladiolus, but did not transmit CMV from four other source plants. In field experiments, only those gladioli planted close to infected gladiolus sources became infected. Oil sprays in combination with coarse nets controlled CMV infection in the field efficiently. [ABSTRACT FROM AUTHOR]

Spread of the aphid-transmitted cucumber mosaic virus (CMV) and potato virus Y (PVY) in pepper plots was markedly reduced by growing the plants under a white coarse-net cover permitting normal development of the plants. This net also reduced the winged aphid population on the plants by more than 40 times. Light grey and yellow nets also reduced virus spread and aphid populations, but were much less effective than white ones. The nets do not act as a mechanical barrier to aphids. It is suggested that under white and grey netting, aphid repellency and microclimatic conditions are the primary causes of virus check, while the controlling effect of the yellow nets may be explained by their being more attractive to aphids than the plants. A reduction of 'background effect' and a limiting of the aphids' vision range by nets are probably other factors involved in the protective mechanism. [ABSTRACT FROM AUTHOR]

Chickweed plants (Stellaria media Vill.), either inoculated with cucumber mosaic virus (CMV) or not, were grown to reproductive maturity at a range of densities, both in monoculture and in mixture. CMV infection did not influence the vegetative growth of plants grown in monoculture. Similarly, the total vegetative production of a population containing infected and healthy plants was the same as that of a monoculture of healthy plants. However, infected plants were disadvantaged when in competition with healthy plants, the disadvantage increasing with density and the proportion of healthy plants. Investment in sexual reproduction was reduced in infected plants at all densities and in healthy plants at high densities. In very hard conditions, plants did not even produce seeds. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, an integrated analysis of the mRNA and protein was performed to identify important putative regulators involved in the transmission of CMV (cucumber mosaic virus) 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 Myzus 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. 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]