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Journal articles on the topic "Virus diseases of maize"

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Poudel, Nabin Sharma, and Kapil Khanal. "Viral Diseases of Crops in Nepal." International Journal of Applied Sciences and Biotechnology 6, no. 2 (June 29, 2018): 75–80. http://dx.doi.org/10.3126/ijasbt.v6i2.19702.

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Viral diseases are the important diseases next to the fungal and bacterial in Nepal. The increase in incidence and severity of viral diseases and emergence of new viral diseases causes the significant yield losses of different crops in Nepal. But the research and studies on plant viral diseases are limited. Most of the studies were focused in viral diseases of rice (Rice tungro virus and Rice dwarf virus), tomato (Yellow leaf curl virus) and potato (PVX and PVY). Maize leaf fleck virus and mosaic caused by Maize mosaic virus were recorded as minor disease of maize. Citrus Tristeza Virus is an important virus of citrus fruit in Nepal while Papaya ringspot potyvirus, Ageratum yellow vein virus (AYVV), Tomato leaf curlJava betasatellite and Sida yellow vein Chinaalphasatellite were recorded from the papaya fruit. The Cucumber mosaic virus (CMV) and Zucchini yellow mosaic potyvirus (ZYMV) are the viral diseases of cucurbitaceous crop reported in Nepal. Mungbean yellow mosaic India virus (MYMIV) found to infect the many crops Limabean, Kidney bean, blackgram and Mungbean. Bean common mosaic necrosis virus in sweet bean, Pea leaf distortion virus (PLDV), Cowpea aphid‐borne mosaic potyvirus (CABMV), Peanut bud necrosis virus (PBNV) in groundnut, Cucumber mosaic virus (CMV). Chili veinal mottle potyvirus (CVMV) and Tomatoyellow leaf curl gemini virus (TYLCV) were only reported and no any further works have been carried out. The 3 virus diseases Soyabean mosaic (SMV), Soybean yellow mosaic virus and Bud blight tobacco ring spot virus (TRSV) were found in soybean.Int. J. Appl. Sci. Biotechnol. Vol 6(2): 75-80
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Snihur, H., A. Kharina, M. Kaliuzhna, V. Chumak, and I. Budzanivska. "First Report of Sugarcane Mosaic Virus in Zea mays L. in Ukraine." Mikrobiolohichnyi Zhurnal 83, no. 5 (October 17, 2021): 58–66. http://dx.doi.org/10.15407/microbiolj83.05.058.

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Maize viral diseases especially maize dwarf mosaic disease (MDMD), which is caused by potyviruses, lead to significant crop losses worldwide. Aim. The aim of this work was to identify the causal agent of mosaic symptoms, observed on maize plants during 2018—2020 in Kyiv region. Methods. Enzyme-linked immunosorbent assay in the DAS-ELISA modification using commercial Loewe Biochemica test systems for Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus (SCMV), Wheat streak mosaic virus (WSMV) were applied to identify the causal agent of maize disease in collected samples. Transmission electron microscopy was used in order to direct viral particle visualisation. Aphids, which are natural vectors of plant viruses, were found on diseased plants. Results. Plants with typical mosaic symptoms were observed in corn crops of the Kyiv region in early June 2018. The pathogen was transmitted by mechanical inoculation to maize and sweet maize plants with the manifestation of mosaic symptoms. Electron microscopy of the sap from diseased plants revealed the presence of flexible filamentous virions 750 nm long and 13 nm in diameter, typical for the genus Potyvirus. In August, mosaic symptoms and aphids Rhopalosiphum padi were found on previously healthy plants in the same maize crop. In 2020, in the same sown area, maize plants were free of viral infection during inspection in June, but a re-inspection in September revealed mosaic symptoms on maize crop and the presence of aphids in the leaf axils. The presence of SCMV in maize samples collected in June and August/September 2018 and 2020, as well as in inoculated maize and sweet maize plants, was confirmed by ELISA using a commercial test system. The obtained data allow suggesting that Rhopalosiphum padi is a natural vector of SCMV in agrocenoses of Ukraine. It should be noted that co-infection with MDMV and WSMV in the affected plants was not detected. Conclusions. This study presents the first report of SCMV in maize in Ukraine.
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Kannan, Maathavi, Ismanizan Ismail, and Hamidun Bunawan. "Maize Dwarf Mosaic Virus: From Genome to Disease Management." Viruses 10, no. 9 (September 13, 2018): 492. http://dx.doi.org/10.3390/v10090492.

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Maize dwarf mosaic virus (MDMV) is a serious maize pathogen, epidemic worldwide, and one of the most common virus diseases for monocotyledonous plants, causing up to 70% loss in corn yield globally since 1960. MDMV belongs to the genus Potyvirus (Potyviridae) and was first identified in 1964 in Illinois in corn and Johnsongrass. MDMV is a single stranded positive sense RNA virus and is transmitted in a non-persistent manner by several aphid species. MDMV is amongst the most important virus diseases in maize worldwide. This review will discuss its genome, transmission, symptomatology, diagnosis and management. Particular emphasis will be given to the current state of knowledge on the diagnosis and control of MDMV, due to its importance in reducing the impact of maize dwarf mosaic disease, to produce an enhanced quality and quantity of maize.
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Cao, Ning, Binhui Zhan, and Xueping Zhou. "Nitric Oxide as a Downstream Signaling Molecule in Brassinosteroid-Mediated Virus Susceptibility to Maize Chlorotic Mottle Virus in Maize." Viruses 11, no. 4 (April 22, 2019): 368. http://dx.doi.org/10.3390/v11040368.

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Maize chlorotic mottle virus (MCMV) infection causes growth abnormalities in maize. Transcriptome sequencing was conducted to compare the global gene expression of MCMV-inoculated plants with that of mock-inoculated plants. Data analyses showed that brassinosteroid (BR)-associated genes were upregulated after MCMV infection. Exogenous 2,4-epibrassinolide (BL) or brassinazole (BRZ) applications indicated that BR pathway was involved in the susceptibility to MCMV infection. In addition, treatment of BL on maize induced the accumulation of nitric oxide (NO), and the changes of NO content played positive roles in the disease incidence of MCMV. Moreover, MCMV infection was delayed when the BL-treated plants were applied with NO scavenger, which suggested that BR induced the susceptibility of maize to MCMV infection in a NO-dependent manner. Further investigation showed the maize plants with knock-down of DWARF4 (ZmDWF4, a key gene of BR synthesis) and nitrate reductase (ZmNR, a key gene of NO synthesis) by virus-induced gene silencing displayed higher resistance to MCMV than control plants. Taken together, our results suggest that BR pathway promotes the susceptibility of maize to MCMV in a NO-dependent manner.
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THOTTAPPILLY, G., N. A. BOSQUE-PÉREZ, and H. W. ROSSEL. "Viruses and virus diseases of maize in tropical Africa." Plant Pathology 42, no. 4 (August 1993): 494–509. http://dx.doi.org/10.1111/j.1365-3059.1993.tb01529.x.

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Ilbağı, Havva, Frank Rabenstein, Antje Habekuss, Frank Ordon, and Ahmet Çıtır. "Incidence of virus diseases in maize fields in the Trakya region of Turkey." Phytoprotection 87, no. 3 (May 29, 2007): 115–22. http://dx.doi.org/10.7202/015853ar.

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Abstract A survey on maize virus diseases was conducted in the Trakya region of Turkey by examining 32 496 and 46 871 plants in 2004 and 2005, respectively. Rates of symptomatic plants were estimated at 3.7 to 63.6%, depending on locations. Biological and serological test results revealed the presence of barley yellow dwarf virus-PAV (BYDV-PAV), maize dwarf mosaic virus (MDMV), sugarcane mosaic virus (SCMV), and Johnson grass mosaic virus (JGMV). One hundred forty-two samples were collected randomly from 6492 symptomatic plants in 2004. Seventy-two out of the 142 samples were infected with MDMV, two were infected with BYDV-PAV, 19 with MDMV and BYDV-PAV, two with MDMV, BYDV-PAV and SCMV, and only one sample contained the four viruses. In 2005, 100 other leaf samples were collected randomly from 11 739 symptomatic maize plants. Serological tests revealed that 50% of the samples were infected with MDMV and SCMV; however, five showed mixed infections of two or three combinations of tested viruses. Individual MDMV, SCMV, BYDV-PAV and JGMV infections were detected in five, three, two and four samples, respectively. Presence of MDMV was confirmed by Western blot analysis and IC-RT-PCR. SCMV was also detected by IC-RT-PCR. This is the first study reporting the detection of SCMV and JGMV on maize plants in Turkey.
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Yahaya, Adama, Danladi B. Dangora, Olufemi J. Alabi, Aisha M. Zongoma, and P. Lava Kumar. "Detection and diversity of maize yellow mosaic virus infecting maize in Nigeria." VirusDisease 30, no. 4 (November 21, 2019): 538–44. http://dx.doi.org/10.1007/s13337-019-00555-0.

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Charles, Alice K., William M. Muiru, Douglas W. Miano, and John W. Kimenju. "Distribution of Common Maize Diseases and Molecular Characterization of Maize Streak Virus in Kenya." Journal of Agricultural Science 11, no. 4 (March 15, 2019): 47. http://dx.doi.org/10.5539/jas.v11n4p47.

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Maize is an important food crop in Kenya and is susceptible to a wide range of diseases. A survey was conducted in 2012 in different agro-ecological zones (AEZ) of Kiambu, Embu and Nakuru counties to determine the distribution of northern leaf blight (NLB), common rust (CR), maize streak disease (MSD), gray leaf spot (GLS), head smut (HS) and common smut (CS). Data collected included prevalence, incidence and severity of each of the diseases. Maize leaf samples infected with MSD were also collected for molecular characterization of Maize streak virus (MSV). Northern leaf blight was reported in all counties surveyed with 100% disease prevalence. Kiambu had the highest incidence (100%) of CR whereas Embu had the highest prevalence (45%) of MSD. The incidences of GLS and HS were very low with averages of below 2.5%. The highest incidence of GLS was in Kiambu (5%). High altitude areas had higher incidences of NLB and GLS while CS and MSD were widespread in the three counties. Comparison of 797 nucleotides from the open reading frame (ORF) C2/C1 of MSV with other sequences from the GenBank showed sequence similarities of 99 to 100% with MSV-A strain. The study revealed that the major foliar diseases of maize are widespread in Kenya and therefore there is need to institute measures to manage these diseases and reduce associated losses. Also, the high percent sequence similarities of MSV indicate low variability which is good for breeders since developed resistant varieties can be adopted over a wider region.
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Batchelor, William D., L. M. Suresh, Xiaoxing Zhen, Yoseph Beyene, Mwaura Wilson, Gideon Kruseman, and Boddupalli Prasanna. "Simulation of Maize Lethal Necrosis (MLN) Damage Using the CERES-Maize Model." Agronomy 10, no. 5 (May 15, 2020): 710. http://dx.doi.org/10.3390/agronomy10050710.

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Maize lethal necrosis (MLN), maize streak virus (MSV), grey leaf spot (GLS) and turcicum leaf blight (TLB) are among the major diseases affecting maize grain yields in sub-Saharan Africa. Crop models allow researchers to estimate the impact of pest damage on yield under different management and environments. The CERES-Maize model distributed with DSSAT v4.7 has the capability to simulate the impact of major diseases on maize crop growth and yield. The purpose of this study was to develop and test a method to simulate the impact of MLN on maize growth and yield. A field experiment consisting of 17 maize hybrids with different levels of MLN tolerance was planted under MLN virus-inoculated and non-inoculated conditions in 2016 and 2018 at the MLN Screening Facility in Naivasha, Kenya. Time series disease progress scores were recorded and translated into daily damage, including leaf necrosis and death, as inputs in the crop model. The model genetic coefficients were calibrated for each hybrid using the 2016 non-inoculated treatment and evaluated using the 2016 and 2018 inoculated treatments. Overall, the model performed well in simulating the impact of MLN damage on maize grain yield. The model gave an R2 of 0.97 for simulated vs. observed yield for the calibration dataset and an R2 of 0.92 for the evaluation dataset. The simulation techniques developed in this study can be potentially used for other major diseases of maize. The key to simulating other diseases is to develop the appropriate relationship between disease severity scores, percent leaf chlorosis and dead leaf area.
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Yu, Cui, Zhang Ai-hong, Ren Ai-jun, and Miao Hong-qin. "Types of Maize Virus Diseases and Progress in Virus Identification Techniques in China." Journal of Northeast Agricultural University (English Edition) 21, no. 1 (March 2014): 75–83. http://dx.doi.org/10.1016/s1006-8104(14)60026-x.

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Dissertations / Theses on the topic "Virus diseases of maize"

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Gomez, Luengo Rodolfo Gustavo. "Proteins and serological relationships of maize mosaic virus isolates and replication of the virus in Maize (Zea Mays L.) protoplasts /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487327695621001.

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Chauhan, Ramola. "A study of filamentous viruses in maize and smallgrains." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/22013.

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Bibliography: pages 175-184.
The occurrence of maize dwarf mosaic virus (MDMV) in field grown maize was investigated. For this purpose, maize showing mosiac symptoms was collected from different maize growing areas in South Africa by Prof. M.B. von Wechmar. These samples from Transvaal, Orange Free State and Natal were then investigated for the presence of MDMV and possible strains of this virus. Three virus isolates were purified and partially characterised. These isolates were serologically compared together with a fourth isolate SCMV 4975, obtained from the U.S., to establish strain relationships.
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Presello, Daniel A. "Studies on breeding of maize for resistance to ear rots caused by Fusarium spp. and on the occurrence of viruses in maize in eastern Canada." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38260.

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Responses from pedigree selection for resistance to gibberella ear rot were assessed in four maize (Zea mays L.) populations, two selected after inoculation of Fusarium graminearum (Schwabe) macroconidia into the silk channel and two selected after inoculation into developing kernels. Responses were significant in both populations selected for silk resistance and in one of the populations selected for kernel resistance. Selection was more effective in later generations and genetic gains were associated with among-family selection but not with within-family selection. Results obtained here indicate that responses to selection could be more efficiently obtained by applying high selection intensities in advanced generations, by managing earlier generations as bulks and by reducing the number of plants per family. In another experiment, a wide sample of Argentine maize germplasm was evaluated for silk and kernel resistance to gibberella ear rot and to fusarium ear rot (caused by F. verticillioides (Saccardo) Nirenberg [=F. moniliforme (Sheldon)]. Several entries exhibited disease resistance in comparison with local check hybrids, particularly for fusarium ear rot, the most prevalent ear rot in Argentina. Results obtained in this study suggested the presence of general mechanisms controlling silk and kernel resistance to both diseases. In a supplementary study, viral diseases were surveyed in maize fields from the provinces of Ontario and Quebec in 1999 and 2000. Barley yellow dwarf was found in 1999. Sugarcane mosaic, maize dwarf mosaic and wheat streak mosaic were found in 2000. These diseases were not important for grain-maize planted in May, the most prevalent kind of maize crop in these provinces. Some of these diseases, such as sugarcane maize mosaic and maize dwarf mosaic were found important only in maize fields planted during or after the month of June, and this is of commercial relevance only for sweet corn.
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Donahue, Patrick J. "Inheritance of reactions to gray leaf spot and maize dwarf mosaic virus in maize and their associations with physiological traits." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54518.

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Gray leaf spot, caused by Cercospora zeae-maydis, can be a yield-limiting factor in maize where continuous minimum tillage practices are followed. Commercial corn hybrids were evaluated for response to gray leaf spot for seven years at two Virginia locations (Shenandoah and Wythe Counties) and one year at a third location in Virginia (Montgomery County). Yield losses, when comparing resistant to susceptible classes, were approximately 2,000 kg ha⁻¹ at Wythe County in 1982, 750 kg ha⁻¹ at Shenandoah County in 1984, and 2,150 kg ha⁻¹ at Montgomery County in 1988. The inheritance of reaction to gray leaf spot was studied using a 14 inbred diallel in Montgomery and Wythe Counties, Virginia in 1987 and 1988 planted in randomized complete block designs. Resistance was found to be highly heritable and controlled by additive gene action. Inbreds producing high yielding, resistant, and agronomically superior hybrids were identified (B68, NC250, Pa875, Va14, Va17, and Va85); and several hybrids between these lines had high levels of resistance, high yield, and good general agronomic characters (B68 x KB1250, KB1250 x Pa875, and NC250 x Pa875). Currently available inbreds could be used to produce hybrids with higher levels of resistance than hybrids currently available to growers, and these could serve as a basis for gray leaf spot breeding programs. Lesion size measurements were not correlated with disease scores. Late-season photosynthesis rates were associated positively with resistance. The hybrids of some inbreds were found to produce high levels of pigment (believed to be anthocyanins) around the gray leaf spot lesions. These did not limit the size of the individual lesion later in the season. Some pigment(s)-producing genotypes were found to be resistant when the pigment character was expressed. This type of resistance must prevent or inhibit infection of the leaf but not later colonization, once established. Maize dwarf mosaic virus (MDMV) also limits maize production in some areas where johnsongrass (Sorghum halepense L.) is a problem. Resistance to MDMV was found to be mainly additive and highly heritable. However, a strong specific combining ability component was found, indicating that the background of the material receiving resistance genes may have a strong effect on the expression of resistance. Inbreds capable of producing high-yielding, resistant, and agronomically acceptable hybrids are available (B68, NC250, A632, Pa875, Va17, and Va85); and several hybrids between these lines have high levels of resistance, high yield, and good general agronomic characters (B68 x KB1250, KB1250 x Pa875, and NC250 x Pa875).
Ph. D.
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Dhau, Inos. "Detection, identification, and mapping of maize streak virus and grey leaf spot diseases of maize using different remote sensing techniques." Thesis, University of Limpopo, 2019. http://hdl.handle.net/10386/2866.

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Thesis (PhD. (Geography)) --University of Limpopo, 2019
Of late climate change and consequently, the spread of crop diseases has been identified as one of the major threat to crop production and food security in subSaharan Africa. This research, therefore, aims to evaluate the role of in situ hyperspectral and new generation multispectral data in detecting maize crop viral and fungal diseases, that is maize streak virus and grey leaf spot respectively. To accomplish this objective; a comparison of two variable selection techniques (Random Forest’s Forward Variable, (FVS) and Guided Regularized Random Forest: (GRRF) was done in selecting the optimal variables that can be used in detecting maize streak virus disease using in-situ resampled hyperspectral data. The findings indicated that the GRRF model produced high classification accuracy (91.67%) whereas the FVS had a slightly lower accuracy (87.60%) based on Hymap when compared to the AISA. The results have shown that the GRRF algorithm has the potential to select compact feature sub sets, and the accuracy performance is better than that of RF’s variable selection method. Secondly, the utility of remote sensing techniques in detecting the geminivirus infected maize was evaluated in this study based on experiments in Ofcolaco, Tzaneen in South Africa. Specifically, the potential of hyperspectral data in detecting different levels of maize infected by maize streak virus (MSV) was tested based on Guided Regularized Random Forest (GRRF). The findings illustrate the strength of hyperspectral data in detecting different levels of MSV infections. Specifically, the GRRF model was able to identify the optimal bands for detecting different levels of maize streak disease in maize. These bands were allocated at 552 nm, 603 nm, 683 nm, 881 nm, and 2338 nm. This study underscores the potential of using remotely sensed data in the accurate detection of maize crop diseases such as MSV and its severity which is critical in crop monitoring to foster food security, especially in the resource-limited subSaharan Africa. The study then investigated the possibility to upscale the previous findings to space borne sensor. RapidEye data and derived vegetation indices were tested in detecting and mapping the maize streak virus. The results revealed that the use of RapidEye spectral bands in detection and mapping of maize streak virus disease yielded good classification results with an overall accuracy of 82.75%. The inclusion of RapidEye derived vegetation indices improved the classification accuracies by 3.4%. Due to the cost involved in acquiring commercial images, like xviii RapidEye, a freely available Landsat-8 data can offer a new data source that is useful for maize diseases estimation, in environments which have limited resources. This study investigated the use of Landsat 8 and vegetation indices in estimating and predicting maize infected with maize streak virus. Landsat 8 data produced an overall accuracy of 50.32%. The inclusion of vegetation indices computed from Landsat 8 sensor improved the classification accuracies by 1.29%. Overally, the findings of this study provide the necessary insight and motivation to the remote sensing community, particularly in resource-constrained regions, to shift towards embracing various indices obtained from the readily-available and affordable multispectral Landsat-8 OLI sensor. The results of the study show that the mediumresolution multispectral Landsat 8-OLI data set can be used to detect and map maize streak virus disease. This study demonstrates the invaluable potential and strength of applying the readily-available medium-resolution, Landsat-8 OLI data set, with a large swath width (185 km) in precisely detecting and mapping maize streak virus disease. The study then examined the influence of climatic, environmental and remotely sensed variables on the spread of MSV disease on the Ofcolaco maize farms in Tzaneen, South Africa. Environmental and climatic variables were integrated together with Landsat 8 derived vegetation indices to predict the probability of MSV occurrence within the Ofcolaco maize farms in Limpopo, South Africa. Correlation analysis was used to relate vegetation indices, environmental and climatic variables to incidences of maize streak virus disease. The variables used to predict the distribution of MSV were elevation, rainfall, slope, temperature, and vegetation indices. It was found that MSV disease infestation is more likely to occur on low-lying altitudes and areas with high Normalised Difference Vegetation Index (NDVI) located at an altitude ranging of 350 and 450 m.a.s.l. The suitable areas are characterized by temperatures ranging from 24°C to 25°C. The results indicate the potential of integrating Landsat 8 derived vegetation indices, environmental and climatic variables to improve the prediction of areas that are likely to be affected by MSV disease outbreaks in maize fields in semi-arid environments. After realizing the potential of remote sensing in detecting and predicting the occurrence of maize streak virus disease, the study further examined its potential in mapping the most complex disease; Grey Leaf Spot (GLS) in maize fields using WorldView-2, Quickbird, RapidEye, and Sentinel-2 resampled from hyperspectral data. To accomplish this objective, field spectra were acquired from healthy, moderate and xix severely infected maize leaves during the 2013 and 2014 growing seasons. The spectra were then resampled to four sensor spectral resolutions – namely WorldView-2, Quickbird, RapidEye, and Sentinel-2. In each case, the Random Forest algorithm was used to classify the 2013 resampled spectra to represent the three identified disease severity categories. Classification accuracy was evaluated using an independent test dataset obtained during the 2014 growing season. Results showed that Sentinel-2 achieved the highest overall accuracy (84%) and kappa value (0.76), while the WorldView-2, produced slightly lower accuracies. The 608 nm and 705nm were selected as the most valuable bands in detecting the GLS for Worldview 2, and Sentinel-2. Overall, the results imply that opportunities exist for developing operational remote sensing systems for detection of maize disease. Adoption of such remote sensing techniques is particularly valuable for minimizing crop damage, improving yield and ensuring food security.
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Madzokere, Eugene T. "The phylogeography, epidemiology and determinants of Maize streak virus dispersal across Africa and the adjacent Indian Ocean Islands." University of the Western Cape, 2015. http://hdl.handle.net/11394/4955.

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>Magister Scientiae - MSc
Maize streak disease (MSD), caused by variants of the Maize streak virus (MSV) A strain, is the world's third and Africa’s most important maize foliar disease. Outbreaks of the disease occur frequently and in an erratic fashion across Africa and Islands in the Indian Ocean causing devastating yield losses such that the emergence, resurgence and rapid diffusion of MSV-A variants in this region presents a serious threat to maize production, farmer livelihoods and food security. To compliment current MSD management systems, a total of 689 MSV-A full genomes sampled over a 32 year period (1979-2011) from 20 countries across Africa and the adjacent Indian Ocean Islands, 286 of which were novel, were used to estimate: (i) the levels of genetic diversity using MEGA and the Sequence Demarcation Tool v1.2 (SDT); (ii) the times of occurrence and distribution of recombination using the recombination detection program (RDP v.4) and the genetic algorithm for recombination detection (GARD); (iii) selection pressure on codon positions using PARRIS and FUBAR methods implemented on the DATAMONKEY web server; (iv) reconstruct the history of spatio-temporal diffusion for MSV-A using the discrete phylogeographic models implemented in BEAST v1.8.1; (v) characterize source-sink dynamics and identify predictor variables driving MSV-A dispersal using the generalized linear models, again implemented in BEAST v1.8.1. Isolates used displayed low levels of genetic diversity (0.017 mean pairwise distance and ≥ 98% nucleotide sequence identities), and a well-structured geographical distribution where all of the 233 novel isolates clustered together with the -A1 strains. A total of 34 MSV inter-strain recombination events and 33 MSV-A intra-strain recombination events, 15 of which have not been reported in previous analyses (Owor et al., 2007, Varsani et al., 2008 and Monjane et al., 2011), were detected. The majority of intra-strain MSV-A recombination events detected were inferred to have occurred within the last six decades, the oldest and most conserved of these being events 19, 26 and 28 whereas the most recent events were 8, 16, 17, 21, 23, and 29. Intra-strain recombination events 20, 25 and 33, were widely distributed amongst East African MSV-A samples, whereas events 16, 21 and 23, occurred more frequently within West African MSV-A samples. Events 1, 4, 8, 10, 14, 17, 19, 22, 24, 25, 26, 28, and 29 were more widely distributed across East, West and Southern Africa and the adjacent Indian Ocean Islands. Whereas codon positions 12 and 19 within motif I in the coat protein transcript, and four out of the seven codon positions (147, 166, 195, 203, 242, 262, 267) in the Rep transcript (codons 195 and 203 in the Rb motif and codons 262 and 267 in site B of motif IV), evolved under strong positive selection pressure, those in the movement protein (MP) and RepA protein encoding genes evolved neutrally and under negative selection pressure respectively. Phylogeographic analyses revealed that MSV-A first emerged in Zimbabwe around 1938 (95% HPD 1904 - 1956), and its dispersal across Africa and the adjacent Indian Ocean Islands was achieved through approximately 34 migration events, 19 of which were statistically supported using Bayes factor (BF) tests. The higher than previously reported mean nucleotide substitution rate [9.922 × 10-4 (95% HPD 8.54 × 10-4 to 1.1317 × 10-3) substitutions per site per year)] for the full genome recombination-free MSV-A dataset H estimated was possibly a result of high nucleotide substitution rates being conserved among geminiviruses such as MSV as previously suggested. Persistence of MSV-A was highest in source locations that include Zimbabwe, followed by South Africa, Uganda, and Kenya. These locations were characterized by high average annual precipitation; moderately high average annual temperatures; high seasonal changes; high maize yield; high prevalence of undernourishment; low trade imports and exports; high GDP per capita; low vector control pesticide usage; high percentage forest land area; low percentage arable land; high population densities, and were in close proximity to sink locations. Dispersal of MSV-A was frequent between locations that received high average annual rainfall, had high percentage forest land area, occupied high latitudes and experienced similar climatic seasons, had high GDP per capita and had balanced maize import to export ratios, and were in close geographical proximity.
National Research Foundation (NRF), the Poliomyelitis Research Foundation (PRF), and the Thuthuka Board
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Nhlane, W. G. "Genetic analysis of maize streak virus disease and the combining ability of maize streak resistant and susceptible populations." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282544.

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Fourie, Michelle Louise. "The potential of wheat, maize, lucerne, and soybean as plant borders to reduce aphid-transmitted virus incidence in seed potatoes." Pretoria : [s. n.], 2008. http://upetd.up.ac.za/thesis/available/etd-09042009-172734/.

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Knox, Elizabeth. "Mixed infections of maize dwarf mosaic virus and cucumber mosaic virus in maize." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/21898.

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Bibliography : pages 218-230.
Maize plants collected in three geographically distinct regions of South Africa were found to be doubly infected with maize dwarf mosaic (MDMV) and cucumber mosaic virus (CMV). A mixed infection of these two viruses could be maintained in maize plants grown under laboratory conditions. The possibility of synergism or of an interference mechanism between MDMV and CMV in dual infections was investigated and it was found that prior infection with CMV interfered with subsequent infection by MDMV. MDMV and CMV were shown to be non-persistently transmitted by Myzus persicae, Rhopalosiphum padi and Rhopalosipbum maidis aphids. Protoplasts were isolated from maize seedlings and could be viably maintained for up to 66 hours. The maize protoplasts were infected with CMV and MDMV either singly, or together as a mixed inoculum. Infection curves for each virus were plotted. The presence of CMV in a mixed inoculum appeared to prevent infection of the protoplasts by MDMV. Protoplasts were isolated from plants systemically infected with CMV and/or MDMV. Superinfection of protoplasts prepared from CMV infected seedlings with MDMV was not possible. As a possible vehicle for virus infection of protoplasts liposomes were produced. Initially fluorescent dyes were incorporated in them. These were fused to the maize protoplasts. Attempts were made to encapsulate virus particles in the liposomes and fuse them to maize protoplasts but this was not successful.
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Liu, Huanting. "Molecular biology of maize streak virus movement in maize." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361478.

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Books on the topic "Virus diseases of maize"

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Wallin, J. R. 1983 virus tolerance ratings of maize genotypes grown in Missouri. [Washington, D.C.]: U.S. Dept. of Agriculture, Agricultural Research Service, 1985.

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Nebbache, Salim. The virus-vector relationship of maize streak virus with Cicadulina leafhoppers. Norwich: University ofEast Anglia, 1988.

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Lapierre, Hervé. Virus and virus diseases of Poaceae (Gramineae). Edited by Signoret Pierre A and Institut national de la recherche agronomique (France). Paris: Institut National de la Recherche Agronomique (France), 2004.

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Food, Ontario Ministry of Agriculture and. Virus diseases of soybeans. S.l: s.n, 1988.

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Frank and Bobbie Fenner Conference on Medical Research. (1st 1988 John Curtin School of Medical Research). Immunology of virus diseases. [Canberra]: John Curtin School of Medical Research, 1989.

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da Silva, Suzane Ramos, Fan Cheng, and Shou-Jiang Gao. Zika Virus and Diseases. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119408673.

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Edouard, Kurstak, ed. Control of virus diseases. 2nd ed. New York: Marcel Dekker, 1993.

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Sonenklar, Carol. Virus hunters. Brookfield, Conn: Twenty-First Century Books, 2003.

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El virus. Tlalnepantla, México: Ediciones Selectas Diamante, 2010.

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Matthews, R. E. F. 1921-, ed. Diagnosis of plant virus diseases. Boca Raton: CRC Press, 1993.

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Book chapters on the topic "Virus diseases of maize"

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Gordon, D. T., and G. Thottappilly. "Maize and Sorghum." In Virus and Virus-like Diseases of Major Crops in Developing Countries, 295–336. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-007-0791-7_12.

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Mei, Yu, and Steven A. Whitham. "Virus-Induced Gene Silencing in Maize with a Foxtail mosaic virus Vector." In Maize, 129–39. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7315-6_7.

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Redinbaugh, Margaret G., and Richard C. Pratt. "Virus Resistance." In Handbook of Maize: Its Biology, 251–70. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-79418-1_13.

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Zhou, Tao, Xuedong Liu, and Zaifeng Fan. "Use of a Virus Gene Silencing Vector for Maize Functional Genomics Research." In Maize, 141–50. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7315-6_8.

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Taylor, N. L., and K. H. Quesenberry. "Virus Diseases." In Red Clover Science, 91–96. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-015-8692-4_7.

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Neve, R. A. "Virus diseases." In Hops, 175–93. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3106-3_8.

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Chen, Ren-Gui, Ping Li, Chen Wang, Ming-Yu Xia, Xin-Feng Wu, Cheng Tan, and Ru-Zhi Zhang. "Virus Diseases." In Atlas of Skin Disorders, 3–10. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-8037-1_1.

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Abbas, Muhammad Taqqi, Muhammad Shafiq, Hibba Arshad, Rajia Haroon, Hamza Maqsood, and Muhammad Saleem Haider. "Viral Diseases of Maize." In Cereal Diseases: Nanobiotechnological Approaches for Diagnosis and Management, 83–96. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3120-8_5.

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Libbey, Jane E., and Robert S. Fujinami. "Virus-Induced Immunosuppression." In Polymicrobial Diseases, 375–87. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555817947.ch19.

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Sklenovská, Nikola. "Monkeypox Virus." In Livestock Diseases and Management, 39–68. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2651-0_2.

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Conference papers on the topic "Virus diseases of maize"

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Nyasani, Johnson O. "Thrips as vectors of an emerging maize disease: A case study of maize chlorotic mottle virus." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.105935.

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Moawad, Nevien, and Abdelrahman Elsayed. "Smartphone Application for Diagnosing Maize Diseases in Egypt." In 2020 14th International Conference on Innovations in Information Technology (IIT). IEEE, 2020. http://dx.doi.org/10.1109/iit50501.2020.9299067.

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Redinbaugh, Margaret (Peg). "Vector-virus interactions in maize agroecosystems in East Africa." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.94561.

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Bylici, E. N. "Field assessment of mutant maize lines for resistance to diseases." In Problems of studying the vegetation cover of Siberia. TSU Press, 2020. http://dx.doi.org/10.17223/978-5-94621-927-3-2020-7.

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Sheikh, Md Helal, Tahmina Tashrif Mim, Md Shamim Reza, AKM Shahariar Azad Rabby, and Syed Akhter Hossain. "Detection of Maize and Peach Leaf diseases using Image Processing." In 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT). IEEE, 2019. http://dx.doi.org/10.1109/icccnt45670.2019.8944530.

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Michtchenko, A., A. V. Budagovsky, and O. N. Budagovskaya. "Optical Diagnostics Fungal and Virus Diseases of Plants." In 2015 12th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE). IEEE, 2015. http://dx.doi.org/10.1109/iceee.2015.7357968.

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Verma, Anil, and Biswajit Bhowmik. "Automated Detection of Maize Leaf Diseases in Agricultural Cyber-Physical Systems." In 2022 30th Mediterranean Conference on Control and Automation (MED). IEEE, 2022. http://dx.doi.org/10.1109/med54222.2022.9837122.

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Krishnamoorthi, M., R. S. Sankavi, V. Aishwarya, and B. Chithra. "Maize Leaf Diseases Identification using Data Augmentation and Convolutional Neural Network." In 2021 2nd International Conference on Smart Electronics and Communication (ICOSEC). IEEE, 2021. http://dx.doi.org/10.1109/icosec51865.2021.9591792.

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Gür, A., M. Karakoç, MF Geyik, K. Nas, R. Çevik, AJ Saraç, S. Em, and F. Erdogan. "SAT0135 Association between hepatitis c virus antibody, hepatitis b virus antigen and fibromiyalgia." In Annual European Congress of Rheumatology, Annals of the rheumatic diseases ARD July 2001. BMJ Publishing Group Ltd and European League Against Rheumatism, 2001. http://dx.doi.org/10.1136/annrheumdis-2001.594.

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Wu, Wenjing, Yongqiang Yu, Ruochen Li, and Yehua Tang. "A Novel Virus Propagation Mathematical Model for Infectious Diseases." In 2021 5th International Conference on Communication and Information Systems (ICCIS). IEEE, 2021. http://dx.doi.org/10.1109/iccis53528.2021.9645938.

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Reports on the topic "Virus diseases of maize"

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Jordan, Ramon L., Abed Gera, Hei-Ti Hsu, Andre Franck, and Gad Loebenstein. Detection and Diagnosis of Virus Diseases of Pelargonium. United States Department of Agriculture, July 1994. http://dx.doi.org/10.32747/1994.7568793.bard.

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Pelargonium (Geranium) is the number one pot plant in many areas of the United States and Europe. Israel and the U.S. send to Europe rooted cuttings, foundation stocks and finished plants to supply a certain share of the market. Geraniums are propagated mainly vegetatively from cuttings. Consequently, viral diseases have been and remain a major threat to the production and quality of the crop. Among the viruses isolated from naturally infected geraniums, 11 are not specific to Pelargonium and occur in other crops while 6 other viruses seem to be limited to geranium. However, several of these viruses are not sufficiently characterized to conclude that they are distinct agents and their nomenclature and taxonomy are confusing. The ability to separate, distinguish and detect the different viruses in geranium will overcome obstacles te developing effective detection and certification schemes. Our focus was to further characterize some of these viruses and develop better methods for their detection and control. These viruses include: isolates of pelargonium line pattern virus (PLPV), pelargonium ringspot virus (PelRSV), pelargonium flower break virus (PFBV), pelargonium leaf curl (PLCV), and tomato ringspot virus (TomRSV). Twelve hybridoma cell lines secreting monoclonal antibodies specific to a geranium isolate of TomRSV were produced. These antibodies are currently being characterized and will be tested for the ability to detect TomRSV in infected geraniums. The biological, biochemical and serological properties of four isometric viruses - PLPV, PelRSV, and PFBV (and a PelRSV-like isolate from Italy called GR57) isolated from geraniums exhibiting line and ring pattern or flower break symptoms - and an isolate ol elderbeny latent virus (ELV; which the literature indicates is the same as PelRSV) have been determined Cloned cDNA copies of the genomic RNAs of these viruses were sequenced and the sizes and locations of predicted viral proteins deduced. A portion of the putative replicase genes was also sequenced from cloned RT-PCR fragments. We have shown that, when compared to the published biochemical and serological properties, and sequences and genome organizations of other small isometric plant viruses, all of these viruses should each be considered new, distinct members of the Carmovirus group of the family Tombusviridae. Hybridization assays using recombinant DNA probes also demonstrated that PLPV, PelRSV, and ELV produce only one subgenomic RNA in infected plants. This unusual property of the gene expression of these three viruses suggests that they are unique among the Carmoviruses. The development of new technologies for the detection of these viruses in geranium was also demonstrated. Hybridization probes developed to PFBV (radioactively-labeled cRNA riboprobes) and to PLPV (non-radioactive digoxigenin-labeled cDNAs) were generally shown to be no more sensitive for the detection of virus in infected plants than the standard ELISA serology-based assays. However, a reverse transcriptase-polymerase chain reaction assay was shown to be over 1000 times more sensitive in detecting PFBV in leaf extracts of infected geranium than was ELISA. This research has lead to a better understanding of the identity of the viruses infecting pelargonium and to the development of new tools that can be used in an improved scheme of providing virus-indexed pelargonium plants. The sequence information, and the serological and cloned DNA probes generated from this work, will allow the application of these new tools for virus detection, which will be useful in domestic and international indexing programs which are essential for the production of virus-free germplasm both for domestic markets and the international exchange of plant material.
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Bar-Joseph, Moshe, William O. Dawson, and Munir Mawassi. Role of Defective RNAs in Citrus Tristeza Virus Diseases. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575279.bard.

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This program focused on citrus tristeza virus (CTV), the largest and one of the most complex RNA-plant-viruses. The economic importance of this virus to the US and Israeli citrus industries, its uniqueness among RNA viruses and the possibility to tame the virus and eventually turn it into a useful tool for the protection and genetic improvement of citrus trees justify these continued efforts. Although the overall goal of this project was to study the role(s) of CTV associated defective (d)-RNAs in CTV-induced diseases, considerable research efforts had to be devoted to the engineering of the helper virus which provides the machinery to allow dRNA replication. Considerable progress was made through three main lines of complementary studies. For the first time, the generation of an engineered CTV genetic system that is capable of infecting citrus plants with in vitro modified virus was achieved. Considering that this RNA virus consists of a 20 kb genome, much larger than any other previously developed similar genetic system, completing this goal was an extremely difficult task that was accomplished by the effective collaboration and complementarity of both partners. Other full-length genomic CTV isolates were sequenced and populations examined, resulting in a new level of understanding of population complexities and dynamics in the US and Israel. In addition, this project has now considerably advanced our understanding and ability to manipulate dRNAs, a new class of genetic elements of closteroviruses, which were first found in the Israeli VT isolate and later shown to be omnipresent in CTV populations. We have characterized additional natural dRNAs and have shown that production of subgenomic mRNAs can be involved in the generation of dRNAs. We have molecularly cloned natural dRNAs and directly inoculated citrus plants with 35S-cDNA constructs and have shown that specific dRNAs are correlated with specific disease symptoms. Systems to examine dRNA replication in protoplasts were developed and the requirements for dRNA replication were defined. Several artificial dRNAs that replicate efficiently with a helper virus were created from infectious full-genomic cDNAs. Elements that allow the specific replication of dRNAs by heterologous helper viruses also were defined. The T36-derived dRNAs were replicated efficiently by a range of different wild CTV isolates and hybrid dRNAs with heterologous termini are efficiently replicated with T36 as helper. In addition we found: 1) All CTV genes except of the p6 gene product from the conserved signature block of the Closteroviridae are obligate for assembly, infectivity, and serial protoplast passage; 2) The p20 protein is a major component of the amorphous inclusion bodies of infected cells; and 3) Novel 5'-Co-terminal RNAs in CTV infected cells were characterized. These results have considerably advanced our basic understanding of the molecular biology of CTV and CTV-dRNAs and form the platform for the future manipulation of this complicated virus. As a result of these developments, the way is now open to turn constructs of this viral plant pathogen into new tools for protecting citrus against severe CTV terms and development of virus-based expression vectors for other citrus improvement needs. In conclusion, this research program has accomplished two main interconnected missions, the collection of basic information on the molecular and biological characteristics of the virus and its associated dRNAs toward development of management strategies against severe diseases caused by the virus and building of novel research tools to improve citrus varieties. Reaching these goals will allow us to advance this project to a new phase of turning the virus from a pathogen to an ally.
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Schat, Karel Antoni, Irit Davidson, and Dan Heller. Chicken infectious anemia virus: immunosuppression, transmission and impact on other diseases. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7695591.bard.

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1. Original Objectives. The original broad objectives of the grant were to determine A) the impact of CAV on the generation of cytotoxic T lymphocytes (CTL) to reticuloendotheliosis virus (REV) (CU), B). the interactions between chicken anemia virus (CAV) and Marek’s disease virus (MDV) with an emphasis on horizontal spread of CAV through feathers (KVI), and C) the impact of CAV infection on Salmonella typhimurium (STM) (HUJI). During the third year and the one year no cost extension the CU group included some work on the development of an antigen-antibody complex vaccine for CAV, which was partially funded by the US Poultry and Egg Association. 2. Background to the topic. CAV is a major pathogen causing clinical disease if maternal antibody-free chickens are infected vertically or horizontally between 1 and 14 days of age. Infection after 3 weeks of age when maternal antibodies are not longer present can cause severe subclinical immunosuppression affecting CTL and cytokine expression. The subclinical immunosuppression can aggravate many diseases including Marek’s disease (MD) and several bacterial infections. 3. Major conclusions and achievements. The overall project contributed in the following ways to the knowledge about CAV infection in poultry. As expected CAV infections occur frequently in Israel causing problems to the industry. To control subclinical infections vaccination may be needed and our work indicates that the development of an antigen-antibody complex vaccine is feasible. It was previously known that CAV can spread vertically and horizontally, but the exact routes of the latter had not been confirmed. Our results clearly show that CAV can be shed into the environment through feathers. A potential interaction between CAV and MD virus (MDV) in the feathers was noted which may interfere with MDV replication. It was also learned that inoculation of 7-day-old embryos causes growth retardation and lesions. The potential of CAV to cause immunosuppression was further examined using CTL responses to REV. CTL were obtained from chickens between 36 and 44 days of age with REV and CAV given at different time points. In contrast to our earlier studies, in these experiments we were unable to detect a direct impact of CAV on REV-specific CTL, perhaps because the CTL were obtained from older birds. Inoculation of CAV at one day of age decreased the IgG antibody responses to inactivated STM administered at 10 days of age. 4. Scientific and Agricultural Implications The impact of the research was especially important for the poultry industry in Israel. The producers have been educated on the importance of the disease through the many presentations. It is now well known to the stakeholders that CAV can aggravate other diseases, decrease productivity and profitability. As a consequence they monitor the antibody status of the breeders so that the maternal antibody status of the broilers is known. Also vaccination of breeder flock that remain antibody negative may become feasible further reducing the negative impact of CAV infection. Vaccination may become more important because improved biosecurity of the breeder flocks to prevent avian influenza and Salmonella may delay the onset of seroconversion for CAV by natural exposure resulting in CAV susceptible broilers lacking maternal antibodies. Scientifically, the research added important information on the horizontal spread of CAV through feathers, the interactions with Salmonella typhimurium and the demonstration that antigen-antibody complex vaccines may provide protective immunity.
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Whitham, Steven A., Amit Gal-On, and Tzahi Arazi. Functional analysis of virus and host components that mediate potyvirus-induced diseases. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7591732.bard.

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The mechanisms underlying the development of symptoms in response to virus infection remain to be discovered in plants. Insight into symptoms induced by potyviruses comes from evidence implicating the potyviral HC-Pro protein in symptom development. In particular, recent studies link the development of symptoms in infected plants to HC-Pro's ability to interfere with small RNA metabolism and function in plant hosts. Moreover, mutation of the highly conserved FRNK amino acid motif to FINK in the HC-Pro of Zucchini yellow mosaic virus (ZYMV) converts a severe strain into an asymptomatic strain, but does not affect virus accumulation in cucurbit hosts. The ability of this FINK mutation to uncouple symptoms from virus accumulation creates a unique opportunity to study symptom etiology, which is usually confounded by simultaneous attenuation of both symptoms and virus accumulation. Our goal was to determine how mutations in the conserved FRNK motif affect host responses to potyvirus infection in cucurbits and Arabidopsis thaliana. Our first objective was to define those amino acids in the FRNK motif that are required for symptoms by mutating the FRNK motif in ZYMV and Turnip mosaic virus (TuMV). Symptom expression and accumulation of resulting mutant viruses in cucurbits and Arabidopsis was determined. Our second objective was to identify plant genes associated with virus disease symptoms by profiling gene expression in cucurbits and Arabidopsis in response to mutant and wild type ZYMV and TuMV, respectively. Genes from the two host species that are differentially expressed led us to focus on a subset of genes that are expected to be involved in symptom expression. Our third objective was to determine the functions of small RNA species in response to mutant and wild type HC-Pro protein expression by monitoring the accumulation of small RNAs and their targets in Arabidopsis and cucurbit plants infected with wild type and mutant TuMV and ZYMV, respectively. We have found that the maintenance of the charge of the amino acids in the FRNK motif of HC-Pro is required for symptom expression. Reduced charge (FRNA, FRNL) lessen virus symptoms, and maintain the suppression of RNA silencing. The FRNK motif is involved in binding of small RNA species including microRNAs (miRNA) and short interfering RNAs (siRNA). This binding activity mediated by the FRNK motif has a role in protecting the viral genome from degradation by the host RNA silencing system. However, it also provides a mechanism by which the FRNK motif participates in inducing the symptoms of viral infection. Small RNA species, such as miRNA and siRNA, can regulate the functions of plant genes that affect plant growth and development. Thus, this binding activity suggests a mechanism by which ZYMVHC-Pro can interfere with plant development resulting in disease symptoms. Because the host genes regulated by small RNAs are known, we have identified candidate host genes that are expected to play a role in symptoms when their regulation is disrupted during viral infections. As a result of this work, we have a better understanding of the FRNK amino acid motif of HC-Pro and its contribution to the functions of HC-Pro, and we have identified plant genes that potentially contribute to symptoms of virus infected plants when their expression becomes misregulated during potyviral infections. The results set the stage to establish the roles of specific host genes in viral pathogenicity. The potential benefits include the development of novel strategies for controlling diseases caused by viruses, methods to ensure stable expression of transgenes in genetically improved crops, and improved potyvirus vectors for expression of proteins or peptides in plants.
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Kamp, Jan, Pieter Blok, Gerrit Polder, Jan van der Wolf, and Henk Jalink. Smart disease detection seed potatoes 2015-2018 : Detection of virus and bacterial diseases using vision and sensor technology. Wageningen: Stichting Wageningen Research, Wageningen Plant Research, Business Unit Field Corps, 2020. http://dx.doi.org/10.18174/494707.

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Grafi, Gideon, and Brian Larkins. Endoreduplication in Maize Endosperm: An Approach for Increasing Crop Productivity. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575285.bard.

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The focus of this research project is to investigate the role of endoreduplication in maize endosperm development and the extent to which this process contributes to high levels of starch and storage protein synthesis. Although endoreduplication has been widely observed in many cells and tissues, especially those with high levels of metabolic activity, the molecular mechanisms through which the cell cycle is altered to produce consecutive cycles of S-phase without an intervening M-phase are unknown. Our previous research has shown that changes in the expression of several cell cycle regulatory genes coincide with the onset of endoreduplication. During this process, there is a sharp reduction in the activity of the mitotic cyclin-dependent kinase (CDK) and activation of the S-phase CDK. It appears the M-phase CDK is stable, but its activity is blocked by a proteinaceous inhibitor. Coincidentally, the S-phase checkpoint protein, retinoblastoma (ZmRb), becomes phosphorylated, presumably releasing an E2F-type transcriptional regulator which promotes the expression of genes responsible for DNA synthesis. To investigate the role of these cell cycle proteins in endoreduplication, we have created transgenic maize plants that express various genes in an endosperm-specific manner using a storage protein (g-zein) promoter. During the first year of the grant, we constructed point mutations of the maize M-phase kinase, p34cdc2. One alteration replaced aspartic acid at position 146 with asparagine (p3630-CdcD146N), while another changed threonine 161 to alanine (p3630-CdcT161A). These mutations abolish the activity of the CDK. We hypothesized that expression of the mutant forms of p34cdc2 in endoreduplicating endosperm, compared to a control p34cdc2, would lead to extra cycles of DNA synthesis. We also fused the gene encoding the regulatory subunit of the M- phase kinase, cyclin B, under the g-zein promoter. Normally, cyclin B is expected to be destroyed prior to the onset of endoreduplication. By producing high levels of this protein in developing endosperm, we hypothesized that the M-phase would be extended, potentially reducing the number of cycles of endoreduplication. Finally, we genetically engineered the wheat dwarf virus RepA protein for endosperm-specific expression. RepA binds to the maize retinoblastoma protein and presumably releases E2F-like transcription factors that activate DNA synthesis. We anticipated that inactivation of ZmRb by RepA would lead to additional cycles of DNA synthesis.
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Rong, Hong-guo, Xiao-wen Zhang, Xin Sun, Chen Shen, Wei-jie Yu, Xiao-zhen Lai, Mei Han, Hai Fang, Yu-tong Fei, and Jian-ping Liu. Empirical evidence from Chinese Medicine used for preventing monkeypox and similar contagious diseases: a scoping review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, July 2022. http://dx.doi.org/10.37766/inplasy2022.7.0013.

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Review question / Objective: Whether traditional Chinese medicine could be used for preventing contagious respiratory virus diseases, including monkey pox, smallpox, measles, chickenpox and rubella? Meanwhile, this review aimed at providing the evidence for the global epidemic prevention and control. Background: Monkeypox is an emerging zoonotic infection caused by monkeypox virus (MPXV), which in the past has been primarily detected in West and Central Africa. Since May 2022, 47 countries have reported 3040 monkeypox cases to WHO. Transmission has occurred in many countries that have not previously reported monkeypox cases, and countries in the WHO European region currently report the largest number of cases. As recently recommended by the WHO, monkeypox should be actively monitored and extensively studied worldwide. Traditional Chinese medicine (TCM) has two thousand years of experience for treating infectious pox diseases. WHO also affirmed the contribution of traditional Chinese medicine to the fight against COVID-19. Therefore, we planned to summarized the classical evidence as well as the clinical evidence of TCM for smallpox, measles, chickenpox and rubella, so as to provide evidence for the treatment of monkey pox.
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Rahai, Hamid, and Jeremy Bonifacio. Numerical Investigations of Virus Transport Aboard a Commuter Bus. Mineta Transportation Institute, April 2021. http://dx.doi.org/10.31979/mti.2021.2048.

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The authors performed unsteady numerical simulations of virus/particle transport released from a hypothetical passenger aboard a commuter bus. The bus model was sized according to a typical city bus used to transport passengers within the city of Long Beach in California. The simulations were performed for the bus in transit and when the bus was at a bus stop opening the middle doors for 30 seconds for passenger boarding and drop off. The infected passenger was sitting in an aisle seat in the middle of the bus, releasing 1267 particles (viruses)/min. The bus ventilation system released air from two linear slots in the ceiling at 2097 cubic feet per minute (CFM) and the air was exhausted at the back of the bus. Results indicated high exposure for passengers sitting behind the infectious during the bus transit. With air exchange outside during the bus stop, particles were spread to seats in front of the infectious passenger, thus increasing the risk of infection for the passengers sitting in front of the infectious person. With higher exposure time, the risk of infection is increased. One of the most important factors in assessing infection risk of respiratory diseases is the spatial distribution of the airborne pathogens. The deposition of the particles/viruses within the human respiratory system depends on the size, shape, and weight of the virus, the morphology of the respiratory tract, as well as the subject’s breathing pattern. For the current investigation, the viruses are modeled as solid particles of fixed size. While the results provide details of particles transport within a bus along with the probable risk of infection for a short duration, however, these results should be taken as preliminary as there are other significant factors such as the virus’s survival rate, the size distribution of the virus, and the space ventilation rate and mixing that contribute to the risk of infection and have not been taken into account in this investigation.
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Wasi, Chantapong. Virus Diseases: The Global Challenge to Health for All. Asia-Pacific Congress of Medical Virology (2nd) Held in Bangkok, Thailand on November 17-22, 1991. Abstracts. Fort Belvoir, VA: Defense Technical Information Center, July 1992. http://dx.doi.org/10.21236/ada258158.

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Pawlowski, Wojtek P., and Avraham A. Levy. What shapes the crossover landscape in maize and wheat and how can we modify it. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600025.bard.

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Meiotic recombination is a process in which homologous chromosomes engage in the exchange of DNA segments, creating gametes with new genetic makeup and progeny with new traits. The genetic diversity generated in this way is the main engine of crop improvement in sexually reproducing plants. Understanding regulation of this process, particularly the regulation of the rate and location of recombination events, and devising ways of modifying them, was the major motivation of this project. The project was carried out in maize and wheat, two leading crops, in which any advance in the breeder’s toolbox can have a huge impact on food production. Preliminary work done in the USA and Israeli labs had established a strong basis to address these questions. The USA lab pioneered the ability to map sites where recombination is initiated via the induction of double-strand breaks in chromosomal DNA. It has a long experience in cytological analysis of meiosis. The Israeli lab has expertise in high resolution mapping of crossover sites and has done pioneering work on the importance of epigenetic modifications for crossover distribution. It has identified genes that limit the rates of recombination. Our working hypothesis was that an integrative analysis of double-strand breaks, crossovers, and epigenetic data will increase our understanding of how meiotic recombination is regulated and will enhance our ability to manipulate it. The specific objectives of the project were: To analyze the connection between double-strand breaks, crossover, and epigenetic marks in maize and wheat. Protocols developed for double-strand breaks mapping in maize were applied to wheat. A detailed analysis of existing and new data in maize was conducted to map crossovers at high resolution and search for DNA sequence motifs underlying crossover hotspots. Epigenetic modifications along maize chromosomes were analyzed as well. Finally, a computational analysis tested various hypotheses on the importance of chromatin structure and specific epigenetic modifications in determining the locations of double-strand breaks and crossovers along chromosomes. Transient knockdowns of meiotic genes that suppress homologous recombination were carried out in wheat using Virus-Induced Gene Silencing. The target genes were orthologs of FANCM, DDM1, MET1, RECQ4, and XRCC2.
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