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Viral colonization was substantially reduced in banana plants that were foliar sprayed with Citosan NanoParticle, CS-NPs, solution. Banana plants treated with CS-NPs showed different levels of protection against Banana Streak Virus, BSV, compared with the untreated control plants. Banana plants treated with CS-NPs at a rate of 200 mg L−1, pre-inoculated with BSV, reduced the disease incidence (DI) by 75.00% and disease severity (DS) by 95.3%, compared with untreated plants. Banana plants treated with CS-NPs at a rate of 300 and 400 mg L−1, pre and post-inoculated with BSV, showed a complete reduction in DI and DS, compared to the control. Surprisingly, the inactivation effects were no longer strong enough to prevent viral accumulation and reproduction after 24h. However, foliar spraying of CS-NPs onto banana leaves significantly reduced BSV replication by activating the plant defense and growth response. The maximum up-regulating expression level of an 18.20-fold change was attained with CS-NPs at a rate of 400 mg L−1. Simultaneously, the mRNA accumulation of the PR-1 gene in 200- and 300 mg L−1 CS-NPs treated plants was high, with 12.12- and 10.50-relative expression fold increases, respectively, over the untreated control. Plants treated with Cs-NP showed elevated levels of reactive oxygen species (PR1 and PR2), catalase activity, and peroxidase activity. Interestingly, the NPs also markedly raised the phytohormones ABA and SA levels by 160% and 520%, respectively. [ABSTRACT FROM AUTHOR]

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

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

Information on viral genetics, including their phylogenetic relationship, is valuable in controlling viral infection and screening for the development of virus-resistant cultivars in the future. The objectives of this study were to detect and characterize the Cymbidium mosaic virus (CymMV) from the native orchids of South Kalimantan, Indonesia, by the RT-PCR method. Also, to determine their phylogenetic relationship based on a partial genome of RdRp by the ML and PCA methods. Following RT-PCR analysis, one of 10 samples of native orchids used was positively infected by CymMV. In early detection, the RdRp region of CymMV has approximately 530 bp in size. After being sequenced and aligned with other isolates, this region has 121 polymorphic or mutation sites, a GC content of 45.21%, a transition/transversion bias value of 3.52, and nucleotide diversity (0.0415). The phylogenetic analysis revealed that CymMV from South Kalimantan, Indonesia, has closest related to similar isolates from Korea Type 2 (AF016914.1), Niigata, Japan (AB197937.1), Hawaii (EF125180.1), and Taiwan M2 (EU314803.1), with the coefficient divergence of 0.025. But, it has very distantly related to Hawaii 18-1 (EF125178.1) with a coefficient of 0.142. The results provide urgent information in supporting the native orchid's conservation and breeding efforts, locally and globally, including mitigating or controlling the viral infection and screening for the development of virus-free or resistant cultivars in the future. [ABSTRACT FROM AUTHOR]

Clove oil has the potential to suppress the development of the mosaic virus in patchouli plants, but its effectiveness in the field has not been studied. This study aimed to evaluate the effect of clove nano biopesticide on controlling patchouli mosaic disease. The research was conducted at the Manoko Experimental Garden, Bandung, West Java from March to November 2018. The patchouli used was Patchoulina-2 variety, which originated from the Seed Breeder Garden in Lembang, Bandung. This study was arranged in a Randomized Block Design (RBD), consisting of five treatments and ten replications within each treatment, with one hundred plants in each replication. The results obtained showed that nano biopesticides of citronella, clove, and commercial citronella (Asimbo) were able to reduce the incidence and intensity of mosaic diseases in patchouli plants, showing the efficacy levels of 14.68%, 9.06%, and 5.83%, respectively. The application of citronella and clove biopesticides on Patchoulina-2 every month could increase plant fresh weight, when compared to the plants without treatment. Patchoulina-2 plants treated with nano biopesticides of clove and commercial citronella (Asimbo) showed higher value of fresh weight compared to those treated with citronella nano biopesticide. The clove nano biopesticide can also be developed to control mosaic diseases in patchouli plants.

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Evaluation of resistance of Vigna unguiculata L. landraces, used as green beans, to Aphis craccivora Koch was tested. Eleven landraces and standard genotypes were used in a free choice protocol: BR 17-Gurguéia, VITA 7 (susceptible), BRS Guariba and TVu 408P2 (resistant). A completely randomized blocks design was used with six replicates. Seedlings were infested with five six-day-old adult insects. The number of alive adults after 48 h and of alive nymphs after 96 h was evaluated. The results evidenced that there are high genetic diversity among the landraces, the antibiosis as the main mechanism of resistance. By means of multivariate analysis we suggest crosses among the commercial cultivar BRS Guariba and the most dissimilar varieties CCE-088, CCE-075, CCE-013 and CCE-062 to obtain superior hybrids.

The current study, the mosaic virus disease of Ocimum basilicum L. (sweet basil) was identified and the different effects of three essential oils on growth, oil content and composition as well as reducing CMV disease symptoms of sweet basil plants in vivo. During 2012 season, natural occurrence of mosaic virus disease was observed on sweet basil in Assiut, Egypt. The causal agent of basil mosaic disease was detected as cucumber mosaic virus (CMV) by PCR product that revealed presence of approximately expected size (~ 781 bp) in naturally infected basil. Therefore, a field experiment was carried out during two successive seasons 2013 and 2014 on sweet basil plants at the Experimental Farm of Arab El Awamer Agricultural Research Station, Assiut Governorate, Egypt. Ten treatments of three essential oils extracted from lemongrass (Cymbopogon citratus), rosemary (Rosemarinus officinalis) and peppermint (Mentha piperita L.) plants were applied as foliar spray at 1% concentration before and after inoculation with isolated virus and two controls (healthy and infected plants) were arranged in a randomized complete block design with three replicates. Results revealed that application of essential oils under field condition improved growth and yield (branches, weight of fresh and dry plant (g/plant) as well as essential oil percentage), reduced the CMV disease symptoms compared to untreated infected control. As well as significant increase in total identified of essential oil composition of basil plant. Whereas the treatment with rosemary oil before and after inoculation respectively, was increased in myrcene, linalool when applied before inoculation and with a great increase in 1, 8-cineole when applied after inoculation. Also a great increase was related to peppermint oil treatment for eugenol, myrcene and 1, 8-cineole % before inoculation comparable to untreated infected plants. While, using of peppermint oil significantlyincreased number of branches, fresh and dry weights, essential oil content and composition when applied before inoculation with virus compared to infected and healthy controls. Lemongrass essential oils exhibited a moderate protective effects. Generally, applying of rosemary essential oil as curative seemed to be superior for improving branches, weight of fresh and dry plant (g/plant), and essential oil percentage and composition comparing to other treatments.

We compared reflective plastic and wheat straw mulches with conventional bare soil for managing aphid-borne virus diseases and silverleaf whitefly in cantaloupe. The occurrence of aphid-borne virus diseases was significantly reduced with both mulches as opposed to bare soil, and reflective plastic performed better than wheat straw. Silverleaf whitefly numbers, both adults and nymphs, were reduced equally by plastic mulch and wheat straw, and were significantly lower than with bare soil. Reflective plastic produced mature melons sooner and more cartons per acre than the other production systems. The reflective plastic system also produced a greater number of large-size melons, which are favored in the late-season market. Plants grown over straw mulch produced higher overall yields, including large-size melons, than those grown over bare soil.

Sugarcane mosaic disease poses a serious threat to the sugarcane industry. Many studies have aimed to unravel the molecular mechanism related to sugarcane and mosaic virus interaction. Quantitative reverse transcription (qRT)-PCR in combination with suitable internal reference genes has been widely used for gene expression analysis. In this study, the expression of 33 candidate reference genes and 12 candidate reference miRNAs was analyzed for first time in the leaf samples of three sugarcane genotype infected with Sorghum mosaic virus using the geNorm, NormFinder and deltaCt (deltaCq) algorithms. A comparison of the expression of eIF-4E and three virus-derived siRNA (vsiR9230S, vsiR9058A and miR16) with the normalized unstable and stable reference genes or miRNA indicated that PP2A and miR159 constituted the best single reference gene/miRNA under SrMV infection. We also suggested that both CUL + CAC and miR171+ miR1520 could serve as the most suitable reference gene/miRNA combination. The use of reliable reference genes and miRNAs should improve the accuracy of gene expression analysis in sugarcane leaves under SrMV stress. [ABSTRACT FROM AUTHOR]

Soybean mosaic virus (SMV) and bean yellow mosaic virus (BYMV) are two typical types of viruses that cause mosaic in soybean plants. Multiple viral infections at the same site can lead to 66% to 80% yield reduction. We have aimed to improve SMV and BYMV resistance in Vietnamese soybeans using gene transfer techniques under the mechanism of RNAi. In this study, we present newly generated transgenic tobacco plants carrying RNAi [CPi (SMV-BYMV)] resistance to the two types of viruses; 73.08% of transgenic tobacco lines proved to be fully resistant to SMV and BYMV. In addition, the number of virus copies in transgenic tobacco plants was reduced on average by more than 51% compared to the control plants (wild type). This promising result shows the potential of transerring the CPi (SMV-BYMV) structure in soybean to increase resistance of soybean to SMV and BYMV and advance the aims of antiviral soybean breeding in Vietnam.

The article presents a report on the detection of genetic diversity and biological characterization of watermelon mosaic virus isolates from Iran and Iraq. Topics include that all of the studied isolates showed a low level of diversity in the partial NIb gene; and that the functional or selective constraint of the NIb gene, acts as a replication-associated protein.

The study was aimed to investigate the symptoms, severity and effect on the yield by mosaic virus disease attack on chilli planted on different altitudes in South Sumatra, Indonesia. Survey method and direct observation in the fields were conducted. Samples were taken on purposive samplings. The parameters measured were mosaic symptoms and disease severity in the field, identification of virus pathogen with ELISA and chili production at first harvest. Chilli in all plantations in three altitudes experienced attack by mosaic virus that is Cucumber Mosaic Virus (CMV) with the most severe was at the low altitude, followed by medium and high altitude; that severity of the disease attack had effect on yield. The highest severity in viral attack had lowest yield of chilli was being at the lowest altitude, although not different from the medium altitude, was significantly different from that of highest altitude of the observed chilli plantation. The discrepancy in the severity is apparently due to the influence of environmental factors. Differences in altitude will cause differences in environmental factors such as temperature, rainfall and humidity can affect a host, pathogen and vector. [ABSTRACT FROM AUTHOR]