Tobacco Streak Virus Research Articles

Seed Transmission and Distribution of Tobacco Streak Virus in Six Cultivars of Soybeans

Seed Transmission and Distribution of Tobacco Streak Virus in Six Cultivars of Soybeans

Chemical and physicochemical properties of two strains of tobacco streak virus

The chemical properties of two strains of tobacco streak virus were compared. The two strains elicited similar symptoms in a limited host range and were also similar in the ratio of nucleoprotein components produced in the Nicotiana species used for virus culture, but they were readily distinguishable serologically and also differed in electrophoretic mobility. Chemically, they had the same RNA content and hypochromicity, and similar nucleotide composition, but the amino acid composition of their coat proteins differed markedly, especially in the contents of alanine, aspartic acid, leucine, proline, and valine. Amino acid content and SDS-polyacrylamide gel electrophoresis analysis indicated molecular weights for the protein subunits of about 28,500–30,000 daltons.

Purification and properties of elm mottle virus.

SUMMARYA virus obtained commonly from Wych elm (Ulmus glabra) in Scotland showing ringspot and line‐pattern leaf symptoms was serologically related to elm mottle virus (EMotV) from East Germany. The virus was seed‐borne in elm and was transmitted by inoculation of sap to elm and twenty‐one herbaceous species. No symptoms developed in infected elm seedlings kept in the glasshouse. In Chenopodium quinoa sap, EMotV lost infectivity after diluting to 10‐4, after 10 min at 60 oC, or 9 days at 18 oC. When purified from C. quinoa sap by clarification with n‐butanol (8‐5 %, v/v) and differential centrifugation, preparations contained quasi‐spherical particles mostly 26–29 nm m diameter (mean = 28 nm) which sedimented as three nucleo‐protein components with sedimentation coefficients (so2o, w) of 83, 88 and 1 or S; most infectivity was associated with the 101 S component but infectivity was enhanced by adding the slower sedimenting components.When centrifuged to equilibrium in caesium chloride solution at 4 oC, purified virus preparations were largely degraded and contained many non‐infective particles c. 15–22 nm in diameter, and intact infective particles which formed a band of density c. 1–34 g/cm3.Polyacrylamide gel electrophoresis indicated that EMotV contained a single major protein species of estimated mol. wt. 25000 and five RNA species of estimated mol. wt. 1–30, 1.15, 0–82, 0 39 and 0–30 times106. Gel electrophoresis of RNA extracted from the separated components indicated that the 101 S component contained 1–30 x io6 mol. wt. RNA and the 83 S component 0–82 times 106 mol. wt. RNA. In these and other properties, EMotV resembles the serologically unrelated tobacco streak virus.

Inheritance and recombination of strain-specific characters in tobacco streak virus

The genetics of symptom determinants and serological type of tobacco streak virus (TSV) were investigated by picking single-lesion hybrid clones of virus originating from heterologous combinations of nucleoprotein components of strains with contrasting characters. A dwarfing of chronically diseased Xanthi-nc tobacco leaves required two factors from different components of the HF strain. In hybrid clones between HF and other strains, each factor was usually, but not always, perpetuated in the component that had provided it to the cross, and was masked. Its presence was demonstrated by backcrossing the hybrid to the HF parent or by crossing with other hybrid clones carrying a single dwarfing determinant in the complementary component. Factors conditioning toothed (t) or entire (e) margins on chronically diseased leaves were carried in each of the particle types. These factors were mutually exclusive when both were present in heterologous combinations of particles, the functional type apparently being determined by chance. The presence of two d (dwarfing) determinants masked t or e determinants, but did not prevent their replication. A determinant conditioning failure of Xanthi tobacco to recover from necrotic symptoms was carried only in the top component, and disappeared from functional particles on aging. Determinants for two serological types were also mutually exclusive and were carried by all three particle types. There appeared to be a linkage between the dwarfing determinants and the serological determinants. Recombinations of other characteristics (lesion type on Vigna cylindrica, chronic symptoms on Xanthi tobacco, and serological type) appeared about as often as would be expected on the basis of random assortment. Redundance in genetic information among particle types of TSV is common; recombination greatly increases variation.

Plant Viruses with a Divided Genome

A considerable number of plant viruses produce in infected plants more than one nucleoprotein component. Typical examples are tobacco rattle virus (TRV) , alfalfa mosaic virus (AMV), viruses of the cowpea mosaic virus (CPMV) group, tobacco streak virus (TSV) and brome mosaic virus (BMV). It has been shown in recent years for some of these muItiparticulate viruses that the genetic information necessary for virus multiplication is di­ vided among two or more nucleoprotein components. Discovery of plant viruses with a divided genome has changed the con­ cept of the nature of viruses. The classical concept implied that the mature virus, the ultimate phase of viral development, was a single particle, the vir­ ion, containing the genome of the virus. This is of course still true for many plant viruses, but no longer for all. Several important groups of plant viruses have been recognized to have a genome divided among two or more physi­ cally separable particles. A certain heterogeneity occurs in practically all purified preparations of plant viruses. In preparations of tobacco mosaic virus (TMV) for example, rodshaped particles with a modal length of 300 m,u predominate, but smaller and longer rods occur also. The presence of such particles has been explained by possible fragmentation of 300 mft particles during purification, faulty syn­ thesis of particles, or, in case of longer particles, by aggregation. Such hetero­ geneity is quite normal in preparations of rodshaped and threadlike viruses. Similarly, preparations of spherical viruses may contain some particles with fragmented RNA. This type of particle we shall regard as defective; it con­ sists of viral structural proteins and fragments of the viral genome. It is possi­ ble that these defective particles have some biological significance, and that they can interfere with virus replication. The infectivity of TMV, for exam­ ple, is enhanced by the presence of short particles derived from the virus in the inoculum (23, 37). In these cases it is a question of occurrence of defec­ tive particles, besides nondefective homOlogous virus particles which contain a complete genome necessary for multiplication (36). Heterogeneity in such virus preparations does not reflect functional heterogeneity. This is different from the multiparticulate viruses we will discuss here. Plant viruses with a divided genome are characterized by physical hetero-

Evidence that particle size heterogeneity is the cause of centrifugal heterogeneity in tobacco streak virus

Preparations made from seven strains of tobacco streak virus, obtained from different geographical locations and plant sources, were analyzed for particle heterogeneity using various physical criteria. Centrifugal heterogeneity was shown to be a function of particle size rather than density. Components separable by polyacrylamide gel electrophoresis, again on the basis of size, were identified with the centrifugal components. The significance of size heterogeneity is discussed in relation to particle structure, biological properties, and possible applicability to other isometric plant viruses.

Factors affecting the proportion of nucleoprotein components of tobacco streak virus

Two strains of tobacco streak virus were each purified from tissue of 16 hosts, and the proportion of nucleoprotein components was determined by centrifugation in sucrose density gradients. The proportion was typical of the strain except that strain WC produced significantly less of the T component in Nicotiana affinis and N. glutinosa. Infected Datura stramonium contained more virus of each strain than did other hosts; yields were also high from Vigna cylindrica. The T component was produced in as high a proportion by plants inoculated with only components a and b as by plants inoculated with components a, b, and T. The proportion of the T component in virus purified from plants at different times after inoculation consistently decreased between 24 and 60 hr after inoculation.

Preparation and some properties of the nucleic acid of tobacco streak virus

Ribonucleic acid associated with the viral nucleoprotein components characteristic of selected strains of tobacco streak virus was analyzed by density gradient centrifugation and by separation on polyacrylamide gels. In vitro degradation of the RNA extracted was traced to enzymatic action either during virus purification or nucleic acid extraction. When this was minimized, the results still suggested heterogeneity in middle component RNA such that middle and top nucleoprotein components have an RNA species in common. Conceivably the parallel between this property and the common biological properties of these components is significant.

Peroxidase isoenzymes in leaves of cucumber ( Cucumis sativus L.) cultivars systemically infected with the W strain of cucumber mosaic virus

The isoperoxidases in leaf extracts of healthy and cucumber mosaic virus infected cucumber cultivars of differing susceptibility to infection and of healthy tobacco plants have been examined by disk electrophoresis. The relative intensities of the principal isoperoxidases in zymograms of extracts from systemitically infected cucumber leaves, compared with those of healthy control leaves, were correlated with symptom severity and peroxidase activity. Thus, extracts from infected leaves of the susceptible cultivars Ashley and Marketer, with pronounced symptoms, showed greater intensities of the principal isoperoxidase bands in comparison with extracts of the resistant, almost symptomless cultivar China, and had greater peroxidase activities. The changes in isoperoxidase patternsappeared to be nonspecific responses to infection, although zymograms of extracts from senescing detached leaves of the four cucumber cultivars were not identical to those from virus infected plants. Cucumber mosaic virus infection of both cucumber and tobacco cultivars resulted in increased activity or stimulated synthesis of host isoperoxidases rather than induction of virus specific ones, in support of conclusions reached by other workers, based on experiments with several viruses including tobacco mosaic, tobacco streak, tobacco necrosis and tobacco ringspot viruses.

Tobacco Streak Virus Isolated from Strawberry Infected with Necrotic Shock

Tobacco Streak Virus Isolated from Strawberry Infected with Necrotic Shock

Occurrence of a Strain of Tobacco Streak Virus in North Carolina

Occurrence of a Strain of Tobacco Streak Virus in North Carolina

The Serological Relationship between "Asparagus stunt’ and Tobacco streak viruses

The Serological Relationship between "Asparagus stunt’ and Tobacco streak viruses

The role of particle heterogeneity in infection by tobacco streak virus

Tobacco streak virus was separable by density gradient centrifugation into four types of nueleoprotein particles. These were designated, from the slowest to the most rapidly sedimenting, T, a, b, and c. T and c were noninfectious; a and b were weakly infectious. When mixed in pairs the a plus b pair was highly infective; the other pairs were not. T, when mixed with a plus b mixtures markedly enhanced infectivity, c did not. This pattern of enhanced infectivity was also typical of mixtures of components from different strains. In heterologous mixtures of a and b, the lesions were typical of the strain from which the a component was derived. In three-component mixtures of homologous a and b plus heterologous T, enhanced lesion numbers were due to lesions typical of the strain from which T was derived. To determine whether infectivity of a or b was intrinsic, heterologous mixtures were prepared and reseparated. The separated b component produced lesions typical of the strain which produced it, not the strain which supplied the a component with which it had been mixed. Apparently infectivity of a or b was not due to contamination with the other particle type. Infectivity dilution curves of most isolated a or b components were typical of multiple-hit curves, suggesting that at some infection sites several particles cooperate in supplying a complete complement of factors necessary for infection. T enhanced infectivity of a and b separately when concentrations of each were sufficiently high, but the effect was less marked than when a was mixed with b.

An Oxidation Product of Chlorogenic Acid in Tobacco Leaves Infected With Tobacco Streak Virus

An Oxidation Product of Chlorogenic Acid in Tobacco Leaves Infected With Tobacco Streak Virus

Tobacco Streak Virus Isolated from Soybeans, Glycine max

Tobacco Streak Virus Isolated from Soybeans, Glycine max

Determinação da disseminação do vírus do enrolamento em batatal para semente pelo uso de plantas indicadoras

Foi verificado haver correlação entre a manifestação de sintomas nas plantas indicadoras intercaladas no batatal para semente e a disseminação, nêle, do vírus do enrolamento das fôlhas. Médias de 12 ensaios realizados em vários pontos do Estado de São Paulo deram os seguintes valores: 49,6% em Datura stramonium, 34,0% em Physalis sp. e 28,5% em tomateiro Santa Cruz. Somente 0,9% das plantas de batata mostraram sintomas de infecção primária pelo vírus, embora a infecção no campo tenha realmente sido de 23,6%. É sugerida a introdução do uso de plantas indicadoras na legislação que regulamenta a produção de batata-semente certificada como método auxiliar para estimativa do teor do vírus do enrolamento nos tubérculos produzidos.

Alteration of Tobacco Streak Virus Component Ratios as Influenced by Host and Extraction Procedure

Alteration of Tobacco Streak Virus Component Ratios as Influenced by Host and Extraction Procedure

Purification and some properties of tobacco streak and Tulare apple mosaic viruses.

Abstract Tobacco streak virus (TSV) was stabilized in extracts by 2-mercaptoethanol and, after clarification of the extracts with hydrated calcium phosphate, concentrated by high speed centrifugation. Host protein was removed from concentrated preparations by acid precipitation and by precipitation with γ-globulin of antiserum to host protein. Purification was completed by two cycles of high (40,000 rpm) and low (10,000) speed centrifugation. TSV measured about 28 mμ in diameter. Centrifugation of purified virus on sucrose density gradients resulted in two closely spaced zones, only the lower of which was infective. Material from the upper zone enhanced infectivity of infective virus; enhancement was more pronounced on the host on which the infectivity-dilution curve was abnormally steep. Tulare apple mosaic virus was purified by the procedure used for TSV. It was slightly larger (32–34 mμ in diameter) than TSV, reacted with homologous antiserum but not with TSV antiserum, and was separable on sucrose density gradients into infectious and noninfectious zones.

Moléstias de vírus do algodoeiro

Das quatro moléstias de vírus encontradas até agora nos plantações de algodoeiros no Estado de São Paulo - o mosaico comum (mosaico do Abutilon), o mosaico das nervuras, o mosaico causado pelo virus da necrose branca do fumo e o vermelhão ou antocianose, só a última é de importância econômica. Medidas de controle para esta, baseadas na destruição do inseto vector - o pulgão do algodoeiro (Aphis gossypii) - são preconizadas.

Purificação e estudo de algumas propriedades do vírus da necrose branca do fumo

Experimentos relativos à purificação do vírus da necrose branca do fumo, em geral instável aos processos de purificação, mostraram ser possível obter preparações razoàvelmente homogêneas partindo-se de plantas por êle infetadas. O processo de purificação constou de uma clarificação preliminar através da adsorção de diversos componentes do suco de planta, ao qual foi adicionado dietilditiocarbamato de sódio a 0,1 M e tampão de fosfato pH 8,0 e a 0,1 M em fosfato hidradatado de cálcio, seguida de ultracentrifugações diferenciais. Os resultados das purificações a partir de Nicotiana tabacum L. var. xanthi, Solanum nigrum L. e Datura stramonium L. doentes, mostraram-se consistentes com respeito à presença de pellets após duas ultracentrifugações, o mesmo não acontecendo com as plantas contrôles. Tais preparações apresentaram infetuosidade até o terceiro dia após a extração do suco. Exames ao microscópio eletrônico das suspensões das pellets acima mencionadas em água destilada, mostraram a existência de partículas esferóides com um diâmetro ao redor de 50 milimicra. Injeções em coelho, via íntravenosa, num total de 7 doses de 2-3 ml de suspensão do vírus da necrose branca do fumo, preparadas diariamente pelo processo já referido, mas com uma só ultracentrifugação, provocaram a formação de anticorpos para o mesmo, conforme se pôde constatar pelos testes de precipitina de difusão em ágar.