176 research outputs found
Molecular, serological and biological variation among chickpea chlorotic stunt virus isolates from five countries of North Africa and West Asia
Chickpea chlorotic stunt virus (CpCSV), a proposed new member of the genus Polerovirus (family Luteoviridae), has been reported only from Ethiopia. In attempts to determine the geographical distribution and variability of CpCSV, a pair of degenerate primers derived from conserved domains of the luteovirus coat protein (CP) gene was used for RT-PCR analysis of various legume samples originating from five countries and containing unidentified luteoviruses. Sequencing of the amplicons provided evidence for the occurrence of CpCSV also in Egypt, Morocco, Sudan, and Syria. Phylogenetic analysis of the CP nucleotide sequences of 18 samples from the five countries revealed the existence of two geographic groups of CpCSV isolates differing in CP sequences by 8–10%. Group I included isolates from Ethiopia and Sudan, while group II comprised those from Egypt, Morocco and Syria. For distinguishing these two groups, a simple RFLP test using HindIII and/or PvuII for cleavage of CP-gene-derived PCR products was developed. In ELISA and immunoelectron microscopy, however, isolates from these two groups could not be distinguished with rabbit antisera raised against a group-I isolate from Ethiopia (CpCSV-Eth) and a group-II isolate from Syria (CpCSV-Sy). Since none of the ten monoclonal antibodies (MAbs) that had been produced earlier against CpCSV-Eth reacted with group-II isolates, further MAbs were produced. Of the seven MAbs raised against CpCSV-Sy, two reacted only with CpCSV-Sy and two others with both CpCSV-Sy and -Eth. This indicated that there are group I- and II-specific and common (species-specific) epitopes on the CpCSV CP and that the corresponding MAbs are suitable for specific detection and discrimination of CpCSV isolates. Moreover, CpCSV-Sy (group II) caused more severe stunting and yellowing in faba bean than CpCSV-Eth (group I). In conclusion, our data indicate the existence of a geographically associated variation in the molecular, serological and presumably biological properties of CpCSV
Abstracts of presentations on plant protection issues at the xth international congress of virology: August 11-16,1996 Binyanei haOoma, Jerusalem, Israel Part 2 Plenary Lectures
Survey for legume and cereal viruses in Iraq
A survey was conducted in April 2000 to identify virus diseases affecting legume (chickpea, faba bean and
lentil) and cereal (wheat and barley) crops at different locations in Iraq (Baghdad, Al-Anbar, Diyala, At-Tamim and
Ninawa governorates). The survey covered 54 randomly selected legume fields (36 faba bean, 8 chickpea, and 10
lentil) and 23 cereal fields (18 wheat and 5 barley). All viruses were identified and their incidence determined by
laboratory testing 100–200 randomly collected samples and 20–25 symptomatic samples from each field. A total of
7663 legume and 3455 cereal samples was collected and tested for 12 legume and 5 cereal viruses by tissue blot
immunoassay (TBIA). In faba bean fields, Bean yellow mosaic virus (BYMV, genus Potyvirus, family Potyviridae) was
the most common, followed by Bean leaf roll virus (BLRV, family Luteoviridae). In the 18 most extensively infected
faba bean fields (more than 50%), total virus incidence ranged from 80 to 100%, and BYMV was by far the most
common. Other viruses that were detected in legumes at low incidence were: Alfalfa mosaic virus (AlMV, genus
Alfamovirus, family Bromoviridae), Faba bean necrotic yellows virus (FBNYV, genus Nanovirus), Cucumber mosaic
virus (CMV, genus Cucumovirus, family Bromoviridae), Broad bean wilt virus (BBWV, genus Fabavirus, family
Comoviridae), Beet western yellows virus (BWYV, genus Polerovirus, family Luteoviridae) and Chickpea chlorotic
dwarf virus (CpCDV, genus Mastervirus, family Geminiviridae). This is the first report of FBNYV, BWYV and CpCDV
infecting legumes in Iraq. In the cereal fields, Barley yellow dwarf virus-PAV (BYDV-PAV, genus Luteovirus, family
Luteoviridae) was detected in about 1% of random samples. Virus disease incidence in all cereal fields based on field
observations was less than 5%. Other viruses were rarely detected in cereals: BYDV-MAV (genus Luteovirus, family
Luteoviridae) and Cereal yellow dwarf virus-RPV (CYDV-RPV, genus Polerovirus, family Luteoviridae)
Systematic evaluation of immune regulation and modulation
Cancer immunotherapies are showing promising clinical results in a variety of malignancies. Monitoring the immune as well as the tumor response following these therapies has led to significant advancements in the field. Moreover, the identification and assessment of both predictive and prognostic biomarkers has become a key component to advancing these therapies. Thus, it is critical to develop systematic approaches to monitor the immune response and to interpret the data obtained from these assays. In order to address these issues and make recommendations to the field, the Society for Immunotherapy of Cancer reconvened the Immune Biomarkers Task Force. As a part of this Task Force, Working Group 3 (WG3) consisting of multidisciplinary experts from industry, academia, and government focused on the systematic assessment of immune regulation and modulation. In this review, the tumor microenvironment, microbiome, bone marrow, and adoptively transferred T cells will be used as examples to discuss the type and timing of sample collection. In addition, potential types of measurements, assays, and analyses will be discussed for each sample. Specifically, these recommendations will focus on the unique collection and assay requirements for the analysis of various samples as well as the high-throughput assays to evaluate potential biomarkers
Molecular characterization of a Bean yellow mosaic virus isolate from Syria
Bean yellow mosaic virus (BYMV, genus Potyvirus, family Potyviridae) was studied by comparing sequences from the coat protein (CP) gene of a Syrian isolate with sequences of six other isolates from the NCBI database. A homology tree of the CP sequences was developed using DNAMAN Software. BYMV isolates were grouped into two clusters of which the first comprised the Syrian isolate together with the Indian, Australian and Japanese isolates, and the second the BYMV isolates from China, the Netherlands and the USA. Moreover, the homology tree showed that the Syrian isolate was very close to the Indian one, with 99% homology
Survey of Viruses Affecting Legume Crops in the Amhara and Oromia Regions of Ethiopia
Field surveys were undertaken to identify the viral diseases affecting lentil, faba bean, chickpea, pea,
fenugreek and grass pea in two regions of Ethiopia. The surveys were conducted in the regions of Amhara (Gonder
and Gojam administrative zones) and Oromia (Bale administrative zone) during the 2003/2004 and 2004/2005 growing
seasons, respectively. The survey covered 138 randomly selected fields (48 faba bean, 10 pea, 38 grass pea, 34
chickpea, 8 lentil) in the Amhara region, and 51 legume fields (29 faba bean, 12 pea, 3 lentil, 5 fenugreek, 2 chickpea)
in the Oromia region. Virus disease incidence was determined by laboratory testing of 100–200 randomly-collected
samples from each field against the antisera of 12 legume viruses. Of the 189 fields surveyed, 121 and 7 had, at the
time of the survey, a virus disease incidence of 1% or less and more than 6%, respectively, based on visual inspection
in the field; later laboratory testing showed that the number of fields in these two categories was in fact 99 and 56,
respectively. Serological tests indicated that the most important viruses in the Amhara region were Faba bean necrotic
yellows virus (FBNYV), Bean yellow mosaic virus (BYMV), Pea seed-borne mosaic virus (PSbMV) and the luteoviruses
[e.g. Beet western yellows virus (BWYV), Bean leaf roll virus (BLRV), Soybean dwarf virus (SbDV)]. By contrast, only
FBNYV and the luteoviruses were detected in the Oromia region. Other viruses, such as Broad bean mottle virus
(BBMV) and Alfalfa mosaic virus (AMV), were rarely detected in the Amhara region. This is the first report in Ethiopia
of natural infection of faba bean, pea and fenugreek with SbDV, of fenugreek with BWYV, and of grass pea with BYMV,
PSbMV and BWYV, and it is also the first recorded instance of BBMV infecting legume crops in Ethiopia
Two distinct nanovirus species infecting faba bean in Morocco
Using monoclonal antibodies raised against a Faba bean necrotic yellows virus (FBNYV) isolate from Egypt and a Faba bean necrotic stunt virus (FBNSV) isolate from Ethiopia, a striking serological variability among nanovirus isolates from faba bean in Morocco was revealed. To obtain a better understanding of this nanovirus variability in Morocco, the entire genomes of two serologically contrasting isolates referred to as Mor5 and Mor23 were sequenced. The eight circular ssDNA components, each identified from Mor5- and Mor23-infected tissues and thought to form the complete nanovirus genome, ranged in size from 952 to 1,005 nt for Mor5 and from 980 to 1,004 nt for Mor23 and were structurally similar to previously described nanovirus DNAs. However, Mor5 and Mor23 differed from each other in overall nucleotide and amino acid sequences by 25 and 26%, respectively. Mor23 was most closely related to typical FBNYV isolates described earlier from Egypt and Syria, with which it shared a mean amino acid sequence identity of about 94%. On the other hand, Mor5 most closely resembled a FBNSV isolate from Ethiopia, with which it shared a mean amino acid sequence identity of approximately 89%. The serological and genetic differences observed for Mor5 and Mor23 were comparable to those observed earlier for FBNYV, FBNSV, and Milk vetch dwarf virus. Following the guidelines on nanovirus species demarcation, this suggests that Mor23 and Mor5 represent isolates of FBNYV and FBNSV, respectively. This is the first report not only on the presence of FBNSV in a country other than Ethiopia but also on the occurrence and complete genome sequences of members of two nanovirus species in the same country, thus providing evidence for faba bean crops being infected by members of two distinct nanovirus species in a restricted geographic area
Climate Change and Pathways Used by Pests as Challenges to Plant Health in Agriculture and Forestry
Climate change already challenges people’s livelihood globally and it also affects plant health. Rising temperatures facilitate the introduction and establishment of unwanted organisms, including arthropods, pathogens, and weeds (hereafter collectively called pests). For example, a single, unusually warm winter under temperate climatic conditions may be sufficient to assist the establishment of invasive plant pests, which otherwise would not be able to establish. In addition, the increased market globalization and related transport of recent years, coupled with increased temperatures, has led to favorable conditions for pest movement, invasion, and establishment worldwide. Most published studies indicate that, in general, pest risk will increase in agricultural ecosystems under climate-change scenarios, especially in today’s cooler arctic, boreal, temperate, and subtropical regions. This is also mostly true for forestry. Some pests have already expanded their host range or distribution, at least in part due to changes in climate. Examples of these pests, selected according to their relevance in different geographical areas, are summarized here. The main pathways used by them, directly and/or indirectly, are also discussed. Understanding these pathways can support decisions about mitigation and adaptation measures. The review concludes that preventive mitigation and adaptation measures, including biosecurity, are key to reducing the projected increases in pest risk in agriculture, horticulture, and forestry. Therefore, the sustainable management of pests is urgently needed. It requires holistic solutions, including effective phytosanitary regulations, globally coordinated diagnostic and surveillance systems, pest risk modeling and analysis, and preparedness for pro-active management
Climate change and pathways used by pests as challenges to plant health in agriculture and forestry.
Climate change already challenges people?s livelihood globally and it also affects plant health. Rising temperatures facilitate the introduction and establishment of unwanted organisms, including arthropods, pathogens, and weeds (hereafter collectively called pests). For example, a single, unusually warm winter under temperate climatic conditions may be sufficient to assist the establishment of invasive plant pests, which otherwise would not be able to establish. In addition, the increased market globalization and related transport of recent years, coupled with increased temperatures, has led to favorable conditions for pest movement, invasion, and establishment worldwide. Most published studies indicate that, in general, pest risk will increase in agricultural ecosystems under climate-change scenarios, especially in today?s cooler arctic, boreal, temperate, and subtropical regions. This is also mostly true for forestry. Some pests have already expanded their host range or distribution, at least in part due to changes in climate. Examples of these pests, selected according to their relevance in different geographical areas, are summarized here. The main pathways used by them, directly and/or indirectly, are also discussed. Understanding these path-ways can support decisions about mitigation and adaptation measures. The review concludes that preventive mitigation and adaptation measures, including biosecurity, are key to reducing the projected increases in pest risk in agriculture, horticulture, and forestry. Therefore, the sustainable management of pests is urgently needed. It requires holistic solutions, including effective phytosanitary regulations, globally coordinated diagnostic and surveillance systems, pest risk modeling and analysis, and preparedness for pro-active management
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