bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of Johnsongrass Chlorotic Stripe Mosaic Virus
Authors: Izadpanah K. , Huth W. , Lesemann D. ‐E. , Vetten H. J. 
Published: May 2008

AbstractPhysicochemical, biological, and cytopathological properties of Johnsongrass chlorotic stripe mosaic virus (JCSMV) found in Iran were investigated. Virus particles were polyhedral, showed a knobbed surface structure, were c. 30 nm in diameter and had a buoyant density of 1. 359 g/ml in cesium chloride. Virions contained one major protein with a molecular weight of 41 kd and a single species of ssRNA with a molecular weight of 1. 43 × 106 d. Acid hydrolysis of the virus followed by thin‐layer electrophoresis gave the following molar percentages of the bases: A: 23. 5, G: 27. 5, C: 26 and U: 23. Separation of nucleotides of the viral RNA using alkaline hydrolysis was not successful. Mechanical inoculation of freshly purified virus or isolated RNA failed to infect Johnsongrass or maize plants. The virus was readily detected by ELISA in seeds from infected plants and young seedlings raised from such seeds, but not in later stages of growth. Ultrathin sections of infected cells showed high concentrations of virus particles in the cytoplasm and vacuoles. Virus‐like particles also occurred in the stroma of chloroplasts and mitochondria. Cisternae of endoplasmic reticulum (ER) were often extremely inflated and filled by a fine fibrillar material. Small membrane‐associated vesicles were frequently found in ER elements and occurred also in the permuclear space. Based on particle structure, properties of the nucleic acid, molecular weight of the coat protein and cytopathology, the virus resembles carmoviruses. However, lack of mechanical transmissibility is not known for any virus classified with this group. No serological reaction was detected with a total of 30 antisera to carmoviruses and other isometric viruses.
Histochemistry and Ultrastructure of the Induced Resistance Response of Cucumber Plants to Colletotrichum lagenarium
Authors: Stein Barry D. , Klomparens Karen L. , Hammerschmidt Raymond 
Published: May 2008

AbstractLignin is hypothesized to be a factor in the ability of cucurbits to resist fungal infection. To determine if lignin was present around sites of infection, susceptible cucumber plants and cucumber plants with systemic induced resistance were inoculated with Colletotrichum lagenarium, and the ultrastructure of plant and pathogen was examined 24 to 72 hours later. Conidia produced germ tubes with appressoria within 24 hours of inoculation on both control and induced plants. Penetration of plant epidermal cell walls occurred by 48 hours, and papillae formed at the site of penetration. Both elemental bromine and potassium permanganate were used to histochemically stain for lignin. Potassium permanganate, used together with energy dispersive X‐ray microanalysis (EDS), indicated the presence of lignin in papillae and in electron‐dense areas of plant cell walls directly beneath the appressoria. Using EDS, silicon was shown to be localized in the electron‐dense areas of cucumber leaf cells. This is the first report of silicon in induced cucumber plants. There were no qualitative differences between the resistance reactions of induced and control plants.
Natural Occurrence of Seiridium cardinale on Thuja in Germany
Authors: Urbasch I. 
Published: May 2008

Abstract Seiridium cardinale (Wagener) Sutton & Gibson (syn. Coryneum cardinale Wagener) is the most dangerous parasitic fungus of cypress and other Gupressaceae, already appearing in epidemic proportions, especially in the mediterranean area. Recently (in 1989, 1990 and 1991) this pathogen has been detected in the northern part of Germany (Hamburg and Schleswig‐Holstein) naturally infecting Thuja.The geographical distribution and the progressive spread of S. cardinale is reviewed. Diagnostic features of the fungus, modes of host penetration, principal symptoms of the disease, ways of dispersal and control methods are described.Possible causal factors for the recently observed occurrence of 5. cardinale in the north of Germany are discussed.
Ultrastructure in Bean Leaves Infiltrated with Bacterial Extracellular Polysaccharides
Authors: Stefani E. , Medeghini Bonatti P. 
Published: May 2008

AbstractUltrastructural observations were carried out in bean leaf tissue infiltrated with bacterial extracellular polysaccharides. These investigations revealed changes m the cell fine structure, especially related with chloroplast organization. Up to 24 h after EPS infiltration alterations consisted in irregularly running thylakoids and distortions of stacked regions. Invaginations of the plastid envelope and appearance of cytoplasm pockets inside the stroma were also noted. The most severe alterations, consisting in stroma dilations and envelope infoldings, were noted 24 h after EPS infiltration, parallehng the yellowing of the treated leaf areas; chloroplast shrinkage and collapse of thylakoid system were also sometimes observed. Chloroplast ultrastructure generally recovered 48 h after treatment; at this time local detachment of the plasma membrane and vesicle formation in the periplasmic space were observed, resembling a non specific, locahzed cellular response. The observed, permanent chlorosis and ultrastructural alterations suggest an interference of the EPS in the global metabolism of the bean mesophyll cell.
The Role of Maize in the Epidemiology of Barley Yellow Dwarf Virus in Northeast Spain
Authors: Comas J. , Pons X. , Albajes R. , Plumb R. T. 
Published: May 2008

AbstractBarley yellow dwarf virus has been detected in maize by indirect enzyme‐linked immunosorbent assay (ELISA) and by immunospecific electron microscopy (ISEM). Samples of maize collected in September 1988, 1989 and 1990 showed that this crop is an important reservoir of BYDV; MAV‐like isolates were the most common although PAV‐like and RPV‐like isolates were also present.Earlier research in Spain had shown that PAV‐like isolates were predominant. Thus the evidence from this work that MAV was the main isolate, and very widely spread, is important for future research on BYDV epidemiology in Spain.
Triticum durum Desf. a Further Host of Barley Mild Mosaic Virus (BaMMV)
Authors: Proeseler G. 
Published: May 2008

AbstractAfter mechanical inoculation by rubbing off with infectious plant sap barley mild mosaic virus (BaMMV) was transmitted to 29 provenances and cultivars of Triticum durum Desf. var. africanum Körn. as well as to the Italian durum wheat cvs ‘Valforte’ and ‘Valnova’. The infected plants reacted partially with distinct mosaic symptoms. BaMMV was detected by ELISA and immunoelectron microscopy.
Transmission Electron Microscopy of Susceptible and Resistant Tomato Leaves Following Infection with Pseudomonas syringae pv. tomato
Authors: Varvaro L. , Fanigliulo R. , Babelegoto N. M. 
Published: May 2008

AbstractUltrastructural changes in tomato leaves of susceptible cv. Peto 95 and resistant cv. Ontario 7710 infected with Pseudomonas syringae pv. tomato were followed by transmission electron microscopy. Up to 48 hours from the inoculation host cells of both cultivars looked quite normal and no bacteria were visible in the intercellular spaces; bacterial cells were found only in the substomatal chambers. Afterwards, the leaf cells of cv. Peto 95 began to degenerate and bacteria invaded the intercellular spaces which seemed enlarged. After 15 days the disorganization was complete: tomato cells were plasmolyzed and the intercellular spaces were filled with bacteria. In the leaves of resistant cv. Ontario 7710 no bacteria were observed later than 48 hours and no visible modifications occurred up to 15 days after the inoculation.
Crude Exopolysaccharides (EPS) from Xanthomonas campestris pv. manihotis, Xanthomonas campestris pv. Campestris and Commercial Xanthan Gum as Inducers of Protection in Coffee Plants against Hemileia vastatrix
Authors: Guzzo Sylvia D. , Bach Erna E. , Martins Elzam. F. , Moraes Walkyriab. C. 
Published: May 2008

AbstractFoliar‐applied exopolysaccharides, obtained from bacterial cells of either Xanthomonas campestris pv. manihotis (EPS‐Xcm) or Xanthomonas campestris pv. campestris (EPS‐Xcc), isolate NRRL B‐1459, were tested for their ability to induce local and systemic protection against coffee leaf rust caused by Hemileia vastatrix. Both preparations of EPS were effective in inducing local and systemic protection when applied 72 h before challenge with the pathogen. Protection was also observed when plants were treated with different concentrations of a commercially available preparation of xanthan gum (CXG).Systemic protection was induced by EPS‐Xcm, EPS‐Xcc and CXG even after the removal of the treated leaves immediately before the challenge. Local protection lasted at least 5 weeks, when EPS‐Xcm was applied at the concentration of 100 μg equivalents of glucose/ml. Fluorescent microscopic studies of pathogen development in protected and control leaves indicated that neither the germination, appressoria formation nor the number of infection sites were affected by treatment with EPS‐Xcm.
A New Virus Isolated from an Ash Tree with Die‐Back
Authors: Bertioli D. J. , Hayle A. , Cooper J. I. 
Published: May 2008

AbstractA virus isolated from an ash tree with die‐back has icosahedral virions c. 28 nm in diameter which contain a polyadenlyated and infectious bipartite single stranded RNA genome. The RNAs have M. Wts of c. 2.4 and 2.6 × 106. The virus was transmitted in 5/48 seed from infected Chenopodium quinoa. Serological tests failed to detect any relationships with 10 viruses. cDNA to the viral RNA was cloned. The sequences of the 5′ and 3′ ends of two clones were determined. One of these clones represents the 3′‐terminus of one of the viral genomic fragments. A search of nucleic acid sequence databases showed some similarity of the 3′‐terminal sequence of the virus to the 3′‐terminal sequence of cowpea mosaic virus. The virus is possibly a previously undescribed nepovirus or comovirus.
Designation of Pathotypes of Plant Pathogens
Authors: Limpert Eckhard , Müller Kaspar 
Published: May 2008

AbstractFor evaluation and communication of data on populations of plant pathogens a sensible code to name pathotypes can be extremely helpful. Starting from a coding system proposed by Habgood in 1970, a system, called “coded triplets” is developed which has the same advantages but is easier to understand and to use. This is especially useful as, in the meantime, pathotypes did become increasingly complex due to the increased number of genes conferring race specific resistance in the host. An important advantage of the coded triplets is that codes change only at one digit if, for example, a new differentia) is added or if the pathotype changes from avirulence to virulence or vice versa on a single differential. In this way evoluationary patterns and changes in the pathogen population can be visualized easily. The system is used to describe complex data on haplotypes of the barley mildew pathogen, but it is suited equally well for designation of pathotypes of other pathogens. Some basic principles of coded triplets are similar to octal notation, described by Gilmour in 1973, which has, however, not become widely known. Reasons for this are discussed. – There is a fourth system belonging to the same group of mathematical, condensing codes. As there is reason to believe that the evolution of condensing codes is drawing to an end, the systems are compared extensively, and the benefits of a generally accepted designation are outlined.
The Level of Abutilon Mosaic Geminivirus in Leaf Discs and Wound Callus
Authors: Song J.‐Y. , Jeske H. 
Published: May 2008

AbstractThe level of Abutilon mosaic geminivirus in leaf discs, wound callus and suspension culture was monitored by hybridization. Over 25 days the amount of AbMV DNA decreased in the leaf discs kept under various experimental conditions including different temperatures, light regimes and hormone concentrations. In primary callus or in suspension culture no viral DNA was detectable. When leaf discs were kept in liquid medium instead of on agar plates a shift from viral single‐stranded DNA to replicative double‐stranded DNA was observed when phytohormones were supplied. It is discussed here why under these conditions, rapidly dividing tissues seem to be virus‐free.
Mycoplasma–like Organisms Associated with a Grapevine Yellows Disease Occurring in Italy
Authors: Credi R. 
Published: May 2008

AbstractTransmission electron microscopy of tissues from Vitis vinifera L. plants, naturally infected with a yellows disease similar to flavescence dorée (FD), revealed the presence of pleomorphic mycoplasmalike organisms (MLOs). These occurred in varying concentrations in mature sieve tube elements of leaf veins. Generally the concentration was very low, although large populations of MLOs were found colonizing almost the entire lumen of two cells. The micro–organisms varied considerably in size, shape and electron opacity. Spherical, oval and filamentous forms were recognized. The bodies showed the typical ultrastructural details of other known plant pathogenic MLOs. They were bounded by a smooth trilaminar membrane and contained ribosome–likegranules and DNA–like strands.
A Novel Method for In Situ Hybridization in Fungal Cells based on Pricking Micro–injection of Photobiotin Labelled Probes
Authors: Matsuda Y. , Toyoda H. , Morita M. , Ikeda S. , Tamai T. , Nishiguchi T. , Ouchi S. 
Published: May 2008

AbstractA novel method, a combination of a micro–injection and in situ hybridization cytochemistry, was developed for the examination of gene expression in Erysiphe graminis f. sp. hordei. In view of its high cellular content, hence high probability of hybridization with corresponding probes, cytoplasmic rRNA was chosen as the target and hybridized with a micro–injected photobiotin–labelled nucleic acid probe. The rDNA sequence was isolated from a genomic library of the fungus by the, use of cDNA derived from 28S RNA of Fusarium oxysporum f. sp. lycopersici, and the complementry RNA strand was synthesized in vitro for a probe. Since neither intact nor fixed conidial cells took up FITC–labelled albumin, the photo, biotin–conjugated RNA probe was introduced into cytoplasm of conidiospores by a pricking method. Positive hybridization was visualized by the colour–generating reaction catalyzed by biotinylated enzyme (alkaline phosphatase) which was first bound to the hybridized photobiotinlabelled probe. Specific hybridization was detected in cytoplasm of more than 80% of pricked conidiospores. A similar result was obtained when a probe was introduced into appressoria and haustoria formed on/in barley coleoptile epidermal cells. Hybridization was also observed in these structures when a double–stranded rDNA probe was introduced by pricking.
Differential Patterns of Bacteriolytic Activities in Potato in Comparison to Bacteriophage T4 and Hen Egg White Lysozymes
Authors: Düring K. 
Published: May 2008

AbstractA comparison of the enzymatic activities of endogenous potato bacteriolytic enzymes with bacteriophage T4 and hen egg white lysozyme has been performed. Using Erwinia carotovora atroseptica and Pseudomonas solanacearum as substrates in, comparison to Micrococcus lysodeikticus a differential pattern of bacteriolytic activities could be detected. The expression pattern of endogenous potato lysozymes suggests that their functional activity against phytopathogenic bacteria in planta is unlikely. Antibacterial activities in transformed, T4 lysozyme expressing and non–transformed potato plants are evaluated.
Molecular Cloning, Detection of Chromosomal DNA of the Mycoplasmalike Organism (MLO) Associated with Faba Bean (Vicia faba L.) Phyllody by Southern Blot Hybridization and the Polymerase Chain Reaction (PCR)
Authors: Saeed E. , Seemüller E. , Schneider B. , Saillard C. , Blanchard B. , Bertheau Y. , Cousin M. T. 
Published: May 2008

AbstractDNA from faba bean (Vicia faba L.) phyllody‐diseased periwinle plants was separated from host plant DNA by bisbenzimid‐CsCl buoyant‐density gradient centrifugation. The mycoplasmalike organism (MLO) DNA was used for the construction of DNA probes. Two probes, 1.45 and 1.35 kbp, were selected and used for the detection of MLO DNA associated with faba pean (FBP) and for assessing the genetic relatedness of FBP‐MLO with other mollicutes. The 1.45 kbp DNA probe hybridized with all MLO strains and, with Spiroplasma citri. The 1.35 kbp DNA probe specifically detected the MLO associated with FBP.Moreover, a specific primer pair (E1 and E2) selected from the partially sequenced 1.35 kbp probe allowed amplification of the 1.35 kbp fragment. DNA amplification was obtained also with Crotaltiana saltiana phyllody (Sudan), C. juncea, witches' broom (Thailand), and tomato big‐bud (Australia), but no amplification was obtained in the cases of the healthy control, C. roseus phyllody (isolate n0) from Sudan, clover phyllody, Gladiolus aster yellow and yellow decline of lavender from France. The very strong signal observed in the case of FBP and C. saltiana phyllody agrees with previous results indicating that FBP and C. saltiana phyllody are caused by an identical MLO, and hence, C. saltiana acts as a reservoir of FBP‐MLO in the Sudan. The weak signal obtained in the case of C. juncea witches' broom and tomáto big‐bud indicates partial nucleotide homology. The major interest of this primer pair is the low quantity (as little as 100 pg) of the total DNA of diseased plant required for the detection of the FBP disease and the possibility of detecting genetic relatedness with other MLOs.
Association of the Decline of Nashi Pears with an MLO
Authors: Pollini C. Poggi , Giunchedi L. , Seemüller E. , Lorenz K.‐H. 
Published: May 2008

AbstractMycoplasma‐like organisms (MLOs) were constantly detected by the DAPI technique and by restriction fragment length polymorphism (RFLP) analysis of PCR‐amplified DNA in trees of Pyrus pyrifolia cvs Hosui and Kosui grafted on P. communis, seedlings rootstock with symptoms similar to the slow form of pear decline. These symptoms included upward curling of the leaves along the midrib. Leaves were abnormally thick and later turned reddish while major veins became swollen and brown. Trees with symptoms were usually 4–5 years old and were growing in the major pear areas of central Italy. The incidence of affected trees was particularly high in one orchard adjacent to a pear orchard strongly affected with the slow form of pear decline. In this case the distribution pattern of affected Nashi trees suggests that the causal agent was introduced from the adjacent pear orchard by an aerial vector. Although oriental pears are well‐known hosts of the pear‐decline agent when used as rootstocks of French cultivars, this is the first report of pear decline in P. pyrifolia varieties.
Pseudomonas syringae pv. helianthi (Kawamura 1934) Dye, Wilkie et Young 1978, a Pathogen of Sunflower (Helianthus annuus L.)
Authors: Arsenijević M. , Vennete R. J. , Maširević S. 
Published: May 2008

AbstractAmong the bacterial strains isolated from diseased sunflower leaves, eight were studied in some detail. A fluorescent pseudomonad isolated from necrotic tissues and its reisolates belong to group Ia of phytopathogenic pseudomonads which includes Pseudomonas syringae bacterium. A study of host range indicated that the pathogen infects only sunflower but not the other plant species. Based on the pathogenicity study and biochemical and physiological tests, it was concluded that the pathogen belongs to the bacterium Pseudomonas syringae pv. helianthi.
Isolation and Characterization of Viruses Present in Four Clones of Garlic (Allium sativum) in Venezuela
Authors: Marys E. , Carballo O. , Izaguirre‐Mayoral M. L. 
Published: May 2008

AbstractIsolation and characterization of viruses infecting garlic in Venezuela indicate the presence of onion yellow dwarf virus [OYDV] in most field‐grown plants of the clones Criollo venezolano, Morado peruano and Blanco, while 14% of the Criollo venezolano plants showed co‐infection of leek yellow stripe virus [LYSV] and OYDV. In leaf tissues OYDV showed an average concentration of 165 μg/g fresh wt., the value being similar among clones. In Criollo venezolano plants co‐infected by LYSV and OYDV the concentration of the former was three fold lower than that of OYDV. Serological tests on leaf extracts of garlic plants indicated the absence of the garlic yellow streak virus [GYSV], shallot latent virus [SLV] and garlic latent virus [GLV] in the clones Criollo venezolano, Morado peruano and Blanco. GLV was found to infect plants of the clone Gigante. Physicochemical analysis of purified GLV strongly supports the inclusion of this virus as a definitive member of the carlavirus group.
The Role of Toxin(s) Produced by Germinating Spores of Pyricularia oryzae in Pathogenesis
Authors: Fujita K. , Arase* S. , Hiratsuka H. , Honda Y. , Nozu M. 
Published: May 2008

Abstract Pyricularia oryzae produced toxin(s) during spore germination which induced susceptibility to infection by non‐pathogenic Alternaria alternata of rice leaves. The induced susceptibility was independent of the compatibility between the races of blast fungi used for obtaining the toxin(s) and the rice cultivars used for bioassay. Susceptibility was also induced in other susceptible species (e.g. barley, Italian ryegrass, perennial ryegrass and wheat), results suggesting that the toxin(s), are host‐selective and determine the host specificity at plant species level.
Morphological Variation in Spores of Pyricularia oryzae Cavara
Authors: Arase* S. , Katano Y. , Li X. , Honda Y. , Nozu M. 
Published: May 2008

AbstractTwo mutant isolates of Pyricularia oryzae formed abnormal, longer, cylindrical spores with more septa than those of normal, obpyriform spores of wild isolates. These isolates also produced normal spores, although their number was less than that of the abnormal spores. When normal and abnormal spores were single‐spore‐isolated from the lesions caused by the mutant isolates and inoculated to an agar medium, each colony produced both types of spores, regardless of the type of single spores usedfor inoculation.
Inoculum Sources for the Spread of Leaf Scald Disease of Sugarcane Caused by Xanthomonas albilineans in Guadeloupe
Authors: Klett P. , Rott P. 
Published: May 2008

AbstractLeaf scald of sugarcane, caused by Xanthomonas albilineans, is thought to be spread mainly in infected cuttings and transmitted on infested cutting implements. Several observations made in Guadeloupe indicated that other means of spreading also occur. The dispersal of the pathogen outside sugarcane was investigated with plants inoculated by an antibiotic‐resistant marked strain of X. albilineans and with plants naturally infested with wild strains of the pathogen. The bacteria were isolated in water droplets (rain or dew) on the surface of sugarcane leaves at dawn. It was also detected on the surface of dry leaves during the day by leaf imprinting onto a selective culture medium. The bacteria were much more frequently isolated from the surface of symptomatic leaves than from symptomless ones. Aerial dispersal of X. albilineans was investigated by placing Petri dishes containing selective culture medium between sugarcane plants but without direct contact with the leaves. The pathogen was isolated in four out of 270 dishes which were randomly set 3‐14 h in a diseased field. These results indicated that the pathogen exuded from the leaves and then was spread by aerial means (rain, insects,…) or by leaf contact. The bacteria were also found in roots and rhizospheric soil of infested sugarcane stools suggesting that X. albilineans could be transmitted by root to root contact or by the soil. Finally, isolations of the pathogen in sugarcane inflorescences were positive. So, fuzz transmission may also occur.