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Validation of test methods is required for laboratories seeking ISO 17025 accreditation. Recently developed manuals help choosing relevant performance characteristics to be studied for qualitative tests common in plant virus detec...
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Validation of test methods is required for laboratories seeking ISO 17025 accreditation. Recently developed manuals help choosing relevant performance characteristics to be studied for qualitative tests common in plant virus detection. For routine testing in certification schemes additional information on the plant material is important to determine the scope of the accredited application. For application of virus tests for diagnostic purposes the determination of certain performance charac-teristics is highly recommended. Furthermore, in case of detection of quarantine organisms a confirmation by an alternative test is indispensable.
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There are many diagnostic tests available for the detection of viral pathogens in ornamental crops. With the introduction of rapid sensitive diagnostic tests, the ornamental industry now has tools that provide quick, reliable resu...
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There are many diagnostic tests available for the detection of viral pathogens in ornamental crops. With the introduction of rapid sensitive diagnostic tests, the ornamental industry now has tools that provide quick, reliable results in a short period of time, usually less than 30 minutes. These tests can be used in the laboratory, greenhouse, and field situations e.g. by federal and state inspectors, greenhouse growers and propagators, and diagnostic labs. The rapid diagnostic tests offer those who work with ornamental plants a quick and reliable means to detect viral pathogens.
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Data on the structure and function of movement proteins of tobacco mosaic tobamovirus (TMV) and tomato mosaic tobamovirus (ToMV) in tissues of resistant and susceptible plants are outlined. Investigations with transgenic tobacco l...
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Data on the structure and function of movement proteins of tobacco mosaic tobamovirus (TMV) and tomato mosaic tobamovirus (ToMV) in tissues of resistant and susceptible plants are outlined. Investigations with transgenic tobacco lines with local andsystemic reactions to TMV in terms of correlations between accumulation, amino acid composition, formation of functional or defective transport proteins, infection transport and resistance to viruses are reviewed. The function of movement proteins in other viruses in single and mixed infections is discussed.
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In 2005 a survey was conducted in the main citrus-growing areas of Epirus. Commercial groves and nurseries were inspected for symptoms of virus and virus-like diseases and a total of 123 samples were collected. Molecular hybridisa...
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In 2005 a survey was conducted in the main citrus-growing areas of Epirus. Commercial groves and nurseries were inspected for symptoms of virus and virus-like diseases and a total of 123 samples were collected. Molecular hybridisation was used to test for Citrus tristeza virus (CTV), Citrus psorosis virus (CPsV), Citrus infectious variegation virus (CVV), Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd). Although the results are from a low number of samples, they give a significant insight into the sanitary conditions of the Greek citrus industry, disclosing the presence of CTV mild strains in the North-western area..
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Viral pathogens form an economically important group of obligatory parasites of plants. About nine hundred and seventy seven plant viruses have been described and classified in 14 families and 70 genera. This unique group of patho...
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Viral pathogens form an economically important group of obligatory parasites of plants. About nine hundred and seventy seven plant viruses have been described and classified in 14 families and 70 genera. This unique group of pathogens has complex interactions with their host plants and vectors due to their sophisticated integration in the molecular mechanisms of living cells, interfering with our ability to manage the malfunctions of virus infected plants by curing means. These constraints led to the adoption of the perception that the best protection from virus diseases is by prevention. Many cultural procedures used for virus control are aimed at eradicating or altering one or more of the primary participants in the transmission process (vector, virus source plants and the crop) or prevent their coming together. Part of these control measures were devised to reduce to a maximum extent the number of inoculative vector individuals that are active in the crop or interfere with the trans-mission process at any of its phases, thereby arresting virus spread. Advances in plant virology and a better understanding of plant vector interaction provide innovative strategies based on the formation of mechanical and optical barriers that interfere with the ability of the viral pathogen or its vector to reach the plant and initiate an epidemic.
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A review of cross protection is given. The subjects included are the criteria necessary for adopting cross protection as a management strategy, successful cases of cross protection management of plant viruses and the drawbacks of its use.
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Viruses are obligate intracellular parasites, and need to create a suitable cell environment for viral propagation to complete their life cycle. In order to achieve this, viruses must usurp or interfere with the cellular machinery...
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Viruses are obligate intracellular parasites, and need to create a suitable cell environment for viral propagation to complete their life cycle. In order to achieve this, viruses must usurp or interfere with the cellular machinery. Ubiquitination, a post-translational modification that controls numerous cellular processes, has proven to be a common target for viruses. Recently, geminivirus C2 protein has been shown to interact with the CSN complex and disrupt its activity over CULLIN1, interfering with the function of the CULLIN1-based SCF ubiquitin E3 ligases. Interestingly, overexpression of a given F-box protein may circumvent the general SCF malfunction caused by C2. This result raises the tantalizing idea that geminiviruses might be not only hampering, but also redirecting the activity of SCF complexes, thus co-opting the SCF-mediated ubiquitination pathway. We hypothesize that the mechanism of C2-facilitated co-option of SCF-mediated ubiquitination might not be exclusive for geminiviruses, but rather a common strategy for viruses.
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S. seaforthianum (star potato vine), a species imported from tropical America, is now locally grown in Italy as an ornamental. An apparently new virus (star potato vine mosaic virus) was isolated from S. seaforthianum plants showi...
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S. seaforthianum (star potato vine), a species imported from tropical America, is now locally grown in Italy as an ornamental. An apparently new virus (star potato vine mosaic virus) was isolated from S. seaforthianum plants showing mosaic symptomson the leaves, in central Italy. The virus had pleomorphic particles, spherical (24X18-30 nm) to bacilliform (24X36,42,48 nm) in shape. Virions contained ssRNA, occurring as 6 molecules of c. 3400 (RNA-1), 3030 (RNA-2), 2050 (RNA-3), 840 (RNA-4), 730 (RNA-5) and 330 (RNA-6) nucleotides, and a coat protein of c. 24 kDa. Acyrthosiphon pisum, Aphis gossypii, Myzus persicae, Frankliniella occidentalis and Trialeurodes vaporariorum failed to transmit the virus in lab. tests, but it was easily mechanically transmitted to a wide experimental host range, including species belonging to 10 plant families. Data from the biological characterization of the virus suggest it is a potential danger to cultivated plants.
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Recent trends show that growth in the ornamental horticulture supply industry exceeds growth in consumer demand, resulting in diminished sales growth and downward pressure on prices. Now and in the foreseeable future, the market w...
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Recent trends show that growth in the ornamental horticulture supply industry exceeds growth in consumer demand, resulting in diminished sales growth and downward pressure on prices. Now and in the foreseeable future, the market will be characterized by continuous and unpredictable change. The role of researchers of plant viruses and diseases in such a dynamic and uncertain commercial environment is addressed by examining: (1) the overall size and recent trends in the market for ornamental horticulture products; (2) Dickson's (1992) theory of "competitive rationality" from the marketing literature, which models the dynamics of constantly changing competitive markets of the type found in the ornamental horticulture industry; (3) the vital contribution of research and development scientists to the processes of innovation and imitation in dynamic market systems; and (4) the importance of market-based targeting of research efforts, using knowledge about customer preferences and economic potential andthe need for improving communication and coordination processes in the provision of virus-free plant material. Since the ornamental horticulture industry is likely to face a turbulent and continuously changing external environment in the future, this paper argues that suppliers need to be more alert and innovative in order to find opportunities in precisely this type of market. Firms and individuals who develop such skills will be able to achieve a competitive advantage that will help them succeed andsurvive, while others will face an uncertain future.
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The intensification of ornamental production, increase in protected crop acreage, introduction of contaminated propagation material and outbreaks of new insect biotypes, may all play a role in the establishment and distribution of...
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The intensification of ornamental production, increase in protected crop acreage, introduction of contaminated propagation material and outbreaks of new insect biotypes, may all play a role in the establishment and distribution of new viral diseases. In Israel, virus diseases are economically important due to crop rotation practices. Viruses with a wide host range are well adapted to survive in successive crops of the same plant grown throughout the year. The use of plastic houses favours the introduction of viruses more adapted to tropical and subtropical climates. Many incidences of new virus diseases of ornamentals have been observed in Israel during the past 5 years. In some cases, previously unknown viruses were identified as the causal agents. In other cases, viruses which were known from other ornamental or non-ornamental plants were detected for the first time in new ornamental hosts. The principal propagators in Israel have in recent years employed a variety of techniques to maintain small populations of protected plants that are propagated in large numbers and serve as the principal source of supply for the industry. Many high value crops are produced entirely in plastic houses from propagation to final sale. In spite of the quarantineregulations in Israel, the process of dispersal of pathogens by man continues, especially because it started before virologists could investigate and record events. Intensive research which enables the early recognition of potential dangers, close international cooperation among scientists, advice to growers and traders and governmental measures are necessary in order to recognize potential dangers early and to develop efficient measures for the prevention of major damage. A strict quarantine policy should be followed to prevent the establishment and distribution of new viral pests in the country. Some of the viral diseases affecting ornamental crops in Israel are described.
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