Soybean Mosaic Potyvirus Research Articles

Development of a Viral RdRp-Assisted Gene Silencing System and Its Application in the Identification of Host Factors of Plant (+)RNA Virus.

Gene silencing induced by hairpin RNA or virus infection expression is one of the major tools in genetics studies in plants. However, when dealing with essential genes, virus-induced gene silencing (VIGS) and transgenic expression of hairpin RNA could lead to plant death, while transient expression of hairpin RNA in leaves is often less competent in downregulating target gene mRNA levels. Here, we developed a transient double-stranded RNA (dsRNA) expression system assisted by a modified viral RNA-dependent RNA polymerase (RdRp) in plant leaves. We show that this system is more effective in inducing gene silencing than the intron-spliced hairpin RNA expression. Furthermore, by using this system, we tested the role of the early secretory pathway during infection of Soybean mosaic potyvirus (SMV). We found that key components of the coat protein complex II vesicles are required for the multiplication of SMV. Overall, this dsRNA-based gene silencing system is effective in downregulating plant gene expression and can be used to identify host genes involved in plant-virus interactions.

Research on the Reaction of Soybean Cultivars to Diseases Attack in 2013, in the County of Brăila

Bacterial burning is a widespread disease in soybeans, which occurs most frequently under cold and wet climate. Soybean mosaic potyvirus is spread everywhere in the world wide as the most damaging viral phytopathogens soybeans. Fusarium species can infect plants at any stage of soybean development. The objective of this research was to estimate the degree of attack of Soybean mosaic potyvirus , bacterial burn and Fusarium species in soybeans. The goal was to have the necessary information in making decisions applying for phytosanitary treatments. Three cultivars were tested: PR92M22, PR92B63, PR91M10, and observations were made under natural contamination on the 15th of July and August 30, 2013. In order to know the health of the experimental lot phytosanitary control were carried in R1 and R4 growth stages, specifying the frequency and intensity of the detected pathogens attack. The research was conducted in the experimental fields without irrigation, in Unirea city and in the Great Island, county of BrAƒila. From this paper it can be concluded that one of the main limiting factors in soybean crop is found in a very large extent of the phytosanitary nature, like the attack of the Soybean mosaic potyvirus , bacteria Pseudomonas savastanoi pv. glycinea and Fusarium species. The degree of infection varied from one cultivar to another. The study was developed during the proces of doctoral studies.

Effects of Different Treatments on the Inactivation of Various Seedborne Viruses in Some Vegetables

In this study, we considered the efficacy of seed treatments for the inactivation of some seedborne viruses in tomato, pepper, melon, squash, bean and lettuce seeds, which are essential for human nutrition and seed production in our country. A total of 325 seed samples obtained from various farmers and foundations were tested by DAS-ELISA and RT-PCR procedures. Eight seed lots infected with Tomato mosaic tobamovirus (ToMV), Tobacco mosaic tobamovirus (TMV), Cucumber mosaic cucumovirus (CMV), Soybean mosaic potyvirus (SMV) and Lettuce mosaic potyvirus (LMV) were selected as research materials. Virus inactivation treatments were made by using acetic acid (CH3COOH), hydrogen peroxide (H2O2), hydrochloric acid (HCl), sodium hypochlorite (NaClO), Triton X 100, dry heat, heated water, ozone (O3), and UV (305 nm wavelength). The most effective treatments for reducing virus concentration were HCl, heated water (65 °C) and ozone (10 g m−3). These treatments reduced concentrations of seed-borne viruses in ranges of 51%, 42%, and 32%, respectively. Other treatments were less effective and reduced virus concentrations in the range of 27%–12%. HCl and ozone treatments were the most effective and applicable methods because they did not have negative effect on seed germination.

Effect of a cowpea mild mottle virus isolate on growth and yield of bambara groundnut (<i>Vigna subterranea</i> L.)

Effect of a cowpea mild mottle virus isolate on growth and yield of bambara groundnut (<i>Vigna subterranea</i> L.)

Gene silencing in transgenic soybean plants transformed via particle bombardment.

Transgenes are susceptible to silencing in plants especially when multiple copies of the gene of interest are introduced. Transgenic plants derived by particle bombardment, which is the common method for transforming soybean, have a tendency to have multiple integration events. Three independent transgenic soybean plants obtained via particle bombardment were analyzed for transgene silencing. A GUS transgenic soybean line had at least 100 copies of the GUS gene while there were approximately 60 copies of the transgene in the two soybean lines transformed with a 15-kDa zein storage protein gene from maize. Soybean plants transformed with the GUS gene showed variable GUS expression. The coding region and promoter of the GUS gene in the plants with low expression of GUS were heavily methylated. Variability in GUS expression was observed in the progeny of the high expressors in the T(2) and T(3) generations as well. Expression level of the 15-kDa zein gene in transgenic soybean plants showed correlation with the level of transgene methylation. The helper component-proteinase from potyviruses is known to suppress post-transcriptional gene silencing. Transgenic plants were inoculated with the soybean mosaic potyvirus (SMV) to test possible effects on transgene silencing in soybean. Infection with SMV did not suppress transgene silencing in these plants and suggests that the silencing in these plants may not be due to post-transcriptional gene silencing.

Evaluation of Resistance in Soybean Germplasm to Soybean Mosaic Potyvirus under Field Conditions

Evaluation of Resistance in Soybean Germplasm to Soybean Mosaic Potyvirus under Field Conditions

Effect of Soybean Mosaic Potyvirus on Growth and Yield Components of Commercial Soybean Varieties

Effect of Soybean Mosaic Potyvirus on Growth and Yield Components of Commercial Soybean Varieties

Occurrence and Distribution of Soybean Mosaic Potyvirus in Soybean Crop of North-west Frontier Province, Pakistan and Characterization of Prevalent Isolates

Occurrence and Distribution of Soybean Mosaic Potyvirus in Soybean Crop of North-west Frontier Province, Pakistan and Characterization of Prevalent Isolates

Implications of movement in developing and deploying integrated pest management strategies

To develop an integrated pest management (IPM) program, one must rely on detailed knowledge of pest movement at several levels. The tenets of IPM and the three tiers of information (fundamental, tactical, and operational) needed to deploy an IPM program are considered. I highlight the soybean mosaic potyvirus pathosystem, a pest system that is nearly impossible to control once the pathogen enters a field, to illustrate how the pathogen can be contained through IPM practices, but only with a reasonable understanding of pathogen transport by insect vectors. The virus is transmitted by a suite of aphids with different flight activity modes. Disease spread is rapid and irreversible if initial inoculum is high and vector flight activity is great. For that reason, the management mode must be preventive, not remedial. The complex epidemiology involves vector movement over both landscape and ecoregional scales, and movement, especially as it is influenced by atmospheric motion systems over both scales, should be understood to effectively manage soybean mosaic virus epidemics. The importance of conceptual, simulation, and predictive models that take into consideration vector movement cannot be overstated when dealing with a pest complex of this nature.

Color Classifier for Symptomatic Soybean Seeds Using Image Processing.

Symptoms associated with fungal damage, viral diseases, and immature soybean (Glycine max) seeds were characterized using image processing techniques. A Red, Green, Blue (RGB) color feature-based multivariate decision model discriminated between asymptomatic and symptomatic seeds for inspection and grading. The color analysis showed distinct color differences between the asymptomatic and symptomatic seeds. A model comprising six color features including averages, minimums, and variances for RGB pixel values was developed for describing the seed symptoms. The color analysis showed that color alone did not adequately describe some of the differences among symptoms. Overall classification accuracy of 88% was achieved using a linear discriminant function with unequal priors for asymptomatic and symptomatic seeds with highest probability of occurrence. Individual classification accuracies were asymptomatic 97%, Alternaria spp. 30%, Cercospora spp. 83%, Fusarium spp. 62%, green immature seeds 91%, Phomopsis spp. 45%, soybean mosaic potyvirus (black) 81%, and soybean mosaic potyvirus (brown) 87%. The classifier performance was independent of the year the seed was sampled. The study was successful in developing a color classifier and a knowledge domain based on color for future development of intelligent automated grain grading systems.

First Report of Cowpea Aphid-Borne Mosaic Potyvirus from Cowpeas Grown Commercially in the U.S.

Cowpea aphid-borne mosaic potyvirus (CABMV) is one of several seed-borne viruses known to limit cowpea (Vigna unguiculata (L.) Walp. subsp. unguiculata) production in Africa, Europe, and Asia, but CABMV has not been reported on commercially grown cowpeas in the United States (1). However, a sesame (Sesamum indicum L.)-infecting isolate of CABMV was recently characterized from plants growing near cowpea introduction plots in Georgia (2). In February 1997, we received samples of three seed lots of cowpea cv. Chinese Red that had been harvested in southern Texas during 1996. Approximately 28% of the plants grown from these seed lots expressed strong mosaic symptoms on primary and trifoliate leaves. Viruslike symptoms were reproduced following mechanical transmission to plants of Chinese Red cowpea, Nicotiana benthamiana, and soybean (Glycine max L.) cv. Lee. When Coronet and Pinkeye Purple Hull-BVR cowpeas were inoculated with sap extracts from symptomatic Chinese Red plants, chlorotic lesions developed on inoculated leaves, but only Coronet plants supported symptomless systemic infections. Similarly inoculated plants of Chenopodium quinoa (L.) and common bean (Phaseolus vulgaris L.) cvs. Pinto and Black Valentine developed localized chlorotic lesions. In Ouchterlony gel diffusion assays, extracts from symptomatic cowpea plants did not react with antisera to blackeye cowpea mosaic potyvirus (BlCMV), cucumber mosaic cucu-movirus (CMV), southern bean mosaic sobemovirus, cowpea mosaic comovirus, cowpea severe mosaic comovirus, or cowpea chlorotic mottle bromovirus. In the indirect enzyme-linked immunosorbent assay, sap extracts from symptomatic plants reacted with antiserum to CABMV, giving OD values at A405 of 0.10 to 0.25, and reacted weakly with antiserum to BlCMV, with OD values at A405 less than 0.035. Extracts from healthy control plants gave OD values at A405 less than 0.010. No positive reactions were obtained with antisera to bean yellow mosaic potyvirus, peanut mottle potyvirus, soybean mosaic potyvirus, or CMV. To our knowledge, this is the first report of CABMV in commercially grown cowpea from the U.S.

Transgenic accumulation of two plant virus coat proteins on a single self-processing polypeptide.

An expression cassette based on the highly specific tobacco etch potyvirus (TEV) nuclear inclusion (NIa) proteinase has been developed to produce multiple proteins through the translation of a single self-processing polypeptide. Gene constructs encoding TEV NIa, the tobacco mosaic tobamovirus (TMV) coat protein (CP) and the soybean mosaic potyvirus (SMV) CP were used to develop transgenic tobacco plants. Proper processing of the multifunctional polypeptide was demonstrated, leading to accumulation of separate proteins in planta. Moreover, the viral genes expressed in this way were biologically active and conferred pathogen-derived protection to TMV, TEV and potato potyvirus Y (PVY). Transgenic plants were also derived from gene constructs in which the NIa cleavage site was mutated, resulting in the accumulation of the non-processed polyprotein, as predicted. Although transgenic proteins accumulated in low amounts in all the plant lines analysed, accumulation of the mutant non-processed protein form was greatly increased in plants following infection with TEV, but not TMV, apparently as a consequence of protein stabilization.

Occurrence of Cowpea Stunt Disease Causing Viruses on Wild Bean in Arkansas.

Cucumber mosaic cucumovirus (CMV) and blackeye cowpea mosaic potyvirus (BlCMV) interact synergistically in dually infected plants to cause cowpea stunt disease (1,2). During a July 1996 survey of cowpea stunt-affected fields in the Arkansas River valley, several wild bean (Strophostyles helvola L. Elliott) plants expressing mosaic symptoms were observed and collected. Sap was extracted from symptomatic leaves and used as inoculum to conduct a host range study. Virus symptoms diagnostic for BlCMV, CMV, or cowpea stunt were observed 6 to 8 days post-inoculation on Vigna unguiculata (L.) Walp. subsp. unguiculata cv. Coronet, while chlorotic lesions and mild systemic mosaic symptoms developed on Nicotiana benthamiana. Enzyme-linked immunosorbent assays (ELISAs) conducted on extracts from symptomatic cowpea and N. benthamiana 14 days after inoculation verified the presence of CMV and BlCMV in single and mixed infections. Additional symptomatic wild bean plants were collected from the same site in October 1996. ELISAs and Ouchterlony gel diffusion assays confirmed the presence of CMV and BlCMV, as well as soybean mosaic potyvirus (SMV), cowpea chlorotic mottle bromovirus, and alfalfa mosaic virus (AlMV) in symptomatic wild bean plants. While some of the collected plants were infected with only one virus, others had combined infections of CMV and BlCMV or these two viruses with AlMV. Interestingly, AlMV isolated from wild bean caused symptoms on greenhouse-grown cowpeas that were as severe or more severe than those caused by the cowpea stunt synergy, often resulting in plant death within 8 to 10 days after inoculation. The SMV from wild bean did not induce symptoms on cowpea and was not detected in extracts from inoculated cowpea plants by Ouchterlony gel diffusion assays, but was able to systemically infect soybean (Glycine max L.) cvs. Bragg and Lee. Another virus known to infect cowpea, southern bean mosaic sobemovirus, was not detected in any of the samples tested. To our knowledge, this is the first report that wild bean can serve as an alternate host for cowpea stunt-causing viruses in single and mixed infections. In addition, these data suggest that AlMV may pose a threat to Arkansas-grown cowpeas.

Inheritance of resistance to potyviruses in Phaseolus vulgaris L. III. Cosegregation of phenotypically similar dominant responses to nine potyviruses

We have identified monogenic dominant resistance to azuki bean mosaic poty virus (AzMV), passionfruit woodiness potyvirus-K (PWV-K), zucchini yellow mosaic potyvirus (ZYMV), and a dominant factor that conditioned lethal necrosis to Thailand Passiflora potyvirus (ThPV), in Phaseolus vulgaris 'Black Turtle Soup 1'. Resistance to AzMV, PWV-K, ZYMV, watermelon mosaic potyvirus, cowpea aphid-borne mosaic potyvirus, blackeye cowpea mosaic potyvirus, and lethal necrosis to soybean mosaic potyvirus and ThPV cosegregated as a unit with the I gene for resistance to bean common mosaic potyvirus.

Soybean Mosaic Potyvirus Enhances the Titer of Two Comoviruses in Dually Infected Soybean Plants

Soybean plants dually infected with soybean mosaic potyvirus (SMV) and either one of two comoviruses, cowpea mosaic virus (CMPV) or bean pod mottle virus (BPMV), showed greatly increased symptom severity over that induced by the individual viruses. The titer of the comovirus (but not of SMV) in the dually infected plants was significantly higher than that in singly infected plants. Electron microscopic examination of thin sections of leaves from dually infected plants revealed that both SMV and CPMV (or BPMV) were present in the same cells (...)

Using Mixed Cropping to Limit Seed Mottling Induced by Soybean Mosaic Virus

The spread of aphid-borne soybean mosaic potyvirus (SMV) from inoculated sources was studied in monocultures of soybean and additive mixtures with dwarf (cv. G522DR) or tall (cv. 102F) sorghum. SMV-induced seed mottling, averaged over rows outside the inoculated area, was 4.01% in the soybean monoculture, compared with 2.02 and 2.07% in plots with dwarf and tall sorghum, respectively. Seed mottling decreased rapidly with increasing distance from the inoculum source. Gradients were similar in different treatments, but the intercept was highest in the soybean monoculture (...)