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Yellow Vein Virus (yellow + vein_virus)
Selected AbstractsSurveys for Beet Necrotic Yellow Vein Virus (the Cause of Rhizomania), other Viruses, and Soil-borne Fungi Infecting Sugar Beet in SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002A. M. Mouhanna Abstract Production of sugar beet, the most important source of sugar in Syria, has suffered from many problems in the past, especially from diseases. No previous surveys have been made in Syria for viral diseases and soil-borne fungi of sugar beet. In 1998, samples were collected from plants showing symptoms of virus infection (yellowing, wilting, necrosis and mosaic). Root samples (341) were collected from crops of autumn-sown seed from 115 localities in seven provinces, 173 root samples from spring-sown crops and 39 leaf samples were collected during both seasons. The root samples were tested for the presence of viruses by double antibody sandwich-enzyme-linked immunosorbent assay (ELISA) and triple antibody sandwich-ELISA, and for soil-borne fungi by red plate (Rose Bengal) dishes. We have shown for the first time the presence of Beet necrotic yellow vein virus, Beet soil-borne virus, Beet yellows virus and Beet mild yellowing virus in Syrian sugar beet fields in which Rhizoctonia sp. and Fusarium sp. were also widely distributed. [source] Molecular Characterization of two Distinct Begomoviruses from Ageratum conyzoides and Malvastrum coromandelianum in ChinaJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2006J. F. Huang Abstract Two weed samples, G52 from Ageratum conyzoides and G87 from Malvastrum coromandelianum, showing leaf curling and vein thickening symptoms were collected in Nanning, Guangxi Province, China. The complete nucleotide sequences of DNA-A-like molecules of G52 and G87 were determined to be 2735 and 2745 nucleotides respectively. Both DNA-A molecules have a genomic organization typical of begomoviruses and share 73.4% sequence identity with each other. Sequence comparisons showed that the DNA-A of G52 and G87 were most closely related to those of Ageratum yellow vein virus (AYVV; 85% sequence identity) and Tobacco leaf curl Yunnanvirus (75.7% sequence identity) respectively. Further sequence comparisons showed that G52 has arisen by recombination among viruses related to AYVV, Papaya leaf curl China virus and an unidentified Begomovirus species. The molecular data suggest that G52 and G87 are two distinct begomoviruses, for which the names Ageratum leaf curl virus for G52 and Malvastrum leaf curl virus for G87 are proposed. The satellite DNA, molecule was only found to be associated with G87. G87 DNA, consists of 1354 nucleotides, and shares the highest nucleotide sequence identity (68.9%) with that associated with Sida yellow vein China virus. A defective DNA, molecule was also found to be associated with G87. [source] Molecular Characterization of a Distinct Begomovirus and its Associated Satellite DNA Molecule Infecting Sida acuta in China,JOURNAL OF PHYTOPATHOLOGY, Issue 5 2005Q. Xiong Abstract Three viral isolates Hn8, Hn40 and Hn41 were obtained from Sida acuta showing yellow mosaic symptom in the Hainan province, China. Comparison of partial DNA-A sequences amplified with degenerate primers confirmed the existence of single type of Begomovirus. The complete nucleotide sequence of the DNA-A-like molecule of Hn8 was determined to be 2749 nucleotides, having a typical genetic organization of a Begomovirus. Hn8 DNA-A had the highest sequence identity (78%) with that of Ageratum yellow vein China virus-[G13] (AJ558120), and had less sequence identity with other begomoviruses. Based on the above molecular data, Hn8 was thus considered as a new Begomovirus species, for which the name Sida yellow mosaic China virus (SiYMCNV) is proposed. Satellite DNA- , molecules (Hn8- ,, Hn40- , and Hn41- ,) were found to be associated with Hn8, Hn40 and Hn41 and their complete nucleotide sequences were determined. Sequence analysis showed that Hn8- ,, Hn40- , and Hn41- , shared more than 84% nucleotide sequence identity, and they were different from other characterized DNA- ,, sharing the highest nucleotide sequence identity (47.8%) with DNA- , of Ageratum yellow vein virus. [source] Genome Organization of an Infectious Clone of Tomato Leaf Curl Virus (Philippines), a New Monopartite Begomovirus*JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002Tatsuya Kon Abstract Complete nucleotide sequence of infectious cloned DNA of Tomato leaf curl virus from Philippines (ToLCV-Ph) was determined. The single circular DNA molecule comprises 2755 nucleotides. ToLCV-Ph DNA contains six open reading frames (ORFs) each capable of encoding proteins with a molecular weight greater than 10 kDa. A partial dimeric ToLCV-Ph DNA clone was constructed in a binary vector and used to agroinoculate tomato plants (Lycopersicon esculentum Mill. cv. Zuikou 102). Typical leaf curl symptoms were observed, showing that the single DNA component is sufficient for infectivity. In total nucleotide sequence comparisons with other geminiviruses, ToLCV-Ph was most closely related to Ageratum yellow vein virus (AYVV) (79% identity), ToLCV-Laos (78%), Soyabean crinkle leaf virus -Thailand (78%) and ToLCV-Taiwan (77%). The significant but relatively low sequence identity in the genomic DNA between ToLCV-Ph and other geminiviruses suggests that it is a distinct geminivirus in the genus Begomovirus. [source] Surveys for Beet Necrotic Yellow Vein Virus (the Cause of Rhizomania), other Viruses, and Soil-borne Fungi Infecting Sugar Beet in SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002A. M. Mouhanna Abstract Production of sugar beet, the most important source of sugar in Syria, has suffered from many problems in the past, especially from diseases. No previous surveys have been made in Syria for viral diseases and soil-borne fungi of sugar beet. In 1998, samples were collected from plants showing symptoms of virus infection (yellowing, wilting, necrosis and mosaic). Root samples (341) were collected from crops of autumn-sown seed from 115 localities in seven provinces, 173 root samples from spring-sown crops and 39 leaf samples were collected during both seasons. The root samples were tested for the presence of viruses by double antibody sandwich-enzyme-linked immunosorbent assay (ELISA) and triple antibody sandwich-ELISA, and for soil-borne fungi by red plate (Rose Bengal) dishes. We have shown for the first time the presence of Beet necrotic yellow vein virus, Beet soil-borne virus, Beet yellows virus and Beet mild yellowing virus in Syrian sugar beet fields in which Rhizoctonia sp. and Fusarium sp. were also widely distributed. [source] Identification of differentially expressed root genes upon rhizomania diseaseMOLECULAR PLANT PATHOLOGY, Issue 6 2008LAURE SCHMIDLIN SUMMARY Rhizomania is one of the most devastating sugar beet diseases. It is caused by Beet necrotic yellow vein virus (BNYVV), which induces abnormal rootlet proliferation. To understand better the physiological and molecular basis of the disorder, transcriptome analysis was performed by restriction fragment differential display polymerase chain reaction (RFDD-PCR), which provided differential gene expression profiles between non-infected and infected sugar beet roots. Two distinct viral isolates were used to detect specific or general virus-induced genes. Differentially expressed genes were selected and identified by sequence analysis, followed by reverse Northern and reverse transcriptase PCR experiments. These latter analyses of different plants (Beta vulgaris and Beta macrocarpa) infected under distinct standardized conditions revealed specific and variable expressions. Candidate genes were linked to cell development, metabolism, defence signalling and oxidative stress. In addition, the expression of already characterized genes linked to defence response (pathogenesis-related protein genes), auxin signalling and cell elongation was also studied to further examine some aspects of the disease. Differential expression was retrieved in both B. vulgaris and B. macrocarpa. However, some candidate genes were found to be deregulated in only one plant species, suggesting differential response to BNYVV or specific responses to the BNYVV vector. [source] Effect of sowing date and straw mulch on virus incidence and aphid infestation in organically grown faba beans (Vicia faba)ANNALS OF APPLIED BIOLOGY, Issue 2 2009H. Saucke Abstract The effect of sowing date on aphid infestation and the incidence of aphid-transmitted viruses were investigated in organically managed, small-scale field experiments with two faba bean cultivars over 3 years (2002,04). As an additional factor, straw mulch was applied in 2 of the 3 years shortly before the start of vector activity in May. Virus incidence was determined using enzyme-linked immunosorbent assay and immunoelectron microscopy. Aphid flight activity was monitored using standard yellow water traps. Bean colonising aphids were assessed throughout the vegetation period by counting the number of plants infested with Acyrthosiphon pisum, Megoura viciae and Aphis fabae. Pea enation mosaic virus and bean yellow mosaic virus were the most abundant aphid-transmitted viruses, being detected in 22,54% and 9,69%, respectively, of the total number of virus-infected plants analysed per year. Further aphid-transmitted viruses found in faba bean were bean leaf roll virus, beet western yellows virus, clover yellow vein virus (in 2002) and soybean dwarf virus (in 2004). A. pisum was the predominant aphid species colonising faba bean plants. Early sowing compared with late sowing led to a significant reduction of the total virus incidence in faba bean in all 3 years. However, significantly decreased levels of A. pisum colonisation as a result of early sowing were observed only in 1 year and one cultivar. Irrespective of sowing date, straw mulching had no significant effects on virus incidence and aphid colonisation. Compared with late sowing, early sowing significantly increased bean yield in all 3 years and kernel weight in 2 years, whereas straw mulching had no effect on yield. [source] Potato yellow vein virus: its host range, distribution in South America and identification as a crinivirus transmitted by Trialeurodes vaporariorumANNALS OF APPLIED BIOLOGY, Issue 1 2000L F SALAZAR Summary Sporadic outbreaks of potato yellow vein disease (PYVD) were first observed in the early 1940's by potato growers in Antioquia, Colombia. Long known to be transmitted by the greenhouse whitefly (Trialeurodes vaporariorum), the precise identity of its causal agent (presumably viral in nature) has remained obscure. Here, we present evidence that a closterovirus with a bipartite genome, potato yellow vein virus (PYVV), is associated with PYVD. Electrophoretic analysis revealed that diseased tissue contains 4,5 disease-specific dsRNAs ranging in size from c. 9 000,1 800 bp. RT-PCR reactions containing pairs of degenerate primers directed against conserved motifs in the closterovirus heat-shock protein homologue produced products of the expected sizes. Comparison of the corresponding amino acid sequences revealed striking similarities between PYVV and two bipartite, whitefly-transmitted criniviruses, Cucurbit yellow stunting disorder and Tomato chlorosis viruses. Epidemiological surveys carried out in Rionegro, Colombia identified Polygonum mepalense, Polygonum spp., Rumex obtusifolium, Tagetes spp., and Catharanthus roseus as potential viral reservoirs. PYVV is transmitted through tubers, and visual symptoms alone cannot be used to determine infection status. A sensitive hybridisation-based assay for PYVV has been developed for use in seed certification programmes. [source] Do virus-resistant plants pose a threat to non-target ecosystems?AUSTRAL ECOLOGY, Issue 5 2009Abstract One key environmental risk associated with the release of novel disease-resistant plants is the potential for non-target host populations to acquire resistance genes and undergo enemy release, leading to damage to associated native plant populations in high conservation-value ecosystems. Unfortunately, the dynamics of most natural pathosystems are poorly understood, and risk assessment of disease-resistant plants remains a challenge. Here we describe the first stage of a multi-tiered risk assessment strategy aimed at quantifying potential ecological release in a model pathosystem (the weedy pasture species Trifolium repens infected with Clover yellow vein virus; ClYVV) in order to assess the level of risk posed by genetically modified and conventionally bred disease-resistant host genotypes to non-target plant communities in south-eastern Australia. Glasshouse inoculation and growth experiments using 14 ClYVV isolates and 20 wild T. repens lines collected from high conservation-value montane grassland and woodland communities show that viral infection reduces the survival and growth of host plants by on average 10,50%. However, T. repens lines exhibited variable levels of resistance and tolerance to virus infection and ClYVV isolates differed in infectivity and aggressiveness, with grassland isolates having a greater pathogenic effect on associated host plants than woodland isolates. We conclude that ClYVV potentially plays an important role in limiting the size of T. repens populations in some at-risk non-target ecosystems and that second-tier field experiments are required to adequately quantify the risk associated with the commercial release of V-R T. repens genotypes in Australia. [source] Do virus-resistant plants pose a threat to non-target ecosystems?AUSTRAL ECOLOGY, Issue 5 2009Abstract It has been widely argued that the acquisition of novel disease resistance genes by wild host populations following the release of novel pathogen-resistant plants into agricultural systems could pose a significant threat to non-target plant communities. However, predicting the magnitude of ecological release in wild plant populations following the removal of disease remains a major challenge. In this paper we report on the second phase of a tiered risk assessment designed to investigate the role of disease on host growth, survival, fecundity and fitness in a model pathosystem (the pasture species Trifolium repens infected with Clover yellow vein virus, ClYVV) and to assess the level of risk posed to at-risk native plant communities in southeast Australia by newly developed genetically modified and conventionally bred virus-resistant T. repens genotypes. Multi-year field experiments conducted in woodland and grassland environments using host-pathogen arrays derived from 14 ClYVV isolates and 21 T. repens genotypes indicate that viral infection reduces fecundity, growth and survival of wild T. repens plants but that the severity of these effects depends on host tolerance to infection, isolate aggressiveness and specific spatial and temporal environmental conditions. Demographic modelling showed that by reducing host survival and growth, ClYVV also limits the intrinsic population growth rate and niche size of wild T. repens populations. Given the significant fitness cost associated with viral infection we conclude that virus-resistant T. repens genotypes may pose a threat to some high conservation-value non-target ecosystems in SE Australia. We also argue that long-term, multi-tiered experiments conducted in a range of controlled and non-controlled environments are necessary to detect and accurately quantify risks associated with the release of disease-resistant plants in general. [source] | ||||||||||