bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defense Reactions in Host and Nonhost Plants Against the Soybean Rust Fungus (Phakopsora pachyrhizi Syd.)
Authors: Hoppe H. H. , Koch E. 
Published: May 2008

AbstractGrowth and development of two races of the soybean rust fungus (Phakopsora pachyrhizi Syd.) were compared on host and nonhost plants. Both groups had several lines of defense, each of which could stop a part of attacking uredospores. Germ tubes and appressoria were produced equally well on hosts and nonhosts. A reduced formation of penetration hyphae contributed to the resistance of nonhosts and resistant host genotypes. In the epidermal cells of wheat and barley leaves, lower frequencies of penetration hyphae coincided with the production of papillae‐like structures which were not penetrated. The last line of defense of all nonhosts was localized in the epidermal cell where the growth of the penetration hyphae was arrested definitively. The colony development in these species was suppressed completely. In highly resistant host genotypes the last defense reaction occurred later as a hypersensitive cell collapse which interrupted the growth of the rust colony.
Identification of Alfalfa Mosaic Virus in Greek Alfalfa Crops
Authors: Avgelis A. , Katis N. 
Published: May 2008

AbstractAlfalfa mosaic virus (AMV) was found to be the prevalent virus disease in alfalfa crops in Central and Northern Greece. The virus was identified on the basis of the host symptomatology, aphid and seed transmission, particle morphology and serological tests. AMV was largely detected in commercial seeds of local grown alfalfa cvs by ELISA. Infected seed lots appear to be the main source responsible for the widespread distribution of the virus in Greek alfalfa fields.
Mixed Infection of Asclepias curassavica L. in Ecuador: Rhabdovirus‐like Particles and Phytomonas sp.
Authors: Dollet M. , Gargani D. 
Published: May 2008

AbstractIn Ecuador, some Aselepias curassavica L. plants express leaf yellowing and premature death. Examination of symptomatic leaves by electron microscopy revealed a mixed infection of Phytomonas and Rhabdovirus‐type particles. The origin of the pathological symptoms is discussed.
Effect of Nitrogen Fertilization and Growth Suppression on Pitch Canker Development on Loblolly Pine Seedlings
Authors: Solel Z. , Bruck R. I. 
Published: May 2008

AbstractOne‐yr‐old loblolly pine seedlings of two half‐sib families, grown in sand, were fertilized three times per week with nutrient solution containing 20 μg/ml (low) or 80 μg/ml (high) nitrogen. Nitrogen concentration in the nutrient solution was either constant throughout the experiment, or interehanged after the inoculation of stems or shoots with Fusarium subglutinans, 55 days after initiation of fertilization. Growth was suppressed by a weekly excision of shoots branching from the stem apex. Either high nitrogen nutrition or shoot excision generally enhanced canker elongation on stem inoculated plants; the combination of both was extremely conducive for disease development. With intact plants of family 8–68, interchange of pre‐inoculation low nitrogen nutrition with high nitrogen after inoculation enhanced canker elongation and rate of wilt. Nitrogen content varied in wood, bark and needles, as well as with time intervals, but was consistently in accordance with nitrogen level in the nutrient solution. In shoot excised plants, nitrogen content was higher than in the respective treatment without shoot excision. The higher nitrogen nutrient accelerated disease development on inoculated shoots, compared to low nitrogen, on both pine families. With respective treatments, stem cankers were larger and rates of shoots exhibiting lesions or wilt were higher on plants of family 8–68 than on 8–61. It is postulated that the disease enhancing effect associated with higher nitrogen content in stem tissues results from an increased nitrogen availability to the pathogen.
Rapid Immunofluorescent Detection of the Grapevine Flavescence Doree Mycoplasmalike Organism in the Salivary Glands of the Leafhopper Euscelidius variegates Kbm
Authors: Lherminier J. , Terwisscha van Scheltinga T. , Boudon‐Padieu E. , Caudwell A. 
Published: May 2008

AbstractPolyclonal rabbit antibodies, prepared against partially purified mycoplasmalike‐organisms (MLO) from Grapevine Flavescence Dorée‐infected plant extracts, were used to detect MLO in situ in excised salivary glands of the experimental vector Euscelidius variegates Kbm by an indirect immunofluorescent staining technique. Glands were examined from the fourth to the tenth week after the start of MLO acquisition. MLO detection was compared using this method, the transmission test and the ELISA technique applied to insects corpses after removal of salivary glands.
A Preparation Method of Aspergillus spp. for Scanning Electron Microscopy
Authors: Weidenbornur M. , Uzih A. , Hamacher J. , Hindori H. , Weltzitzien H. C. 
Published: May 2008

AbstractFor scaning electron microscopy (SEM) of Aspergillus flavus Link und A. petraku Vörös. Simultaneous fixation and drying in osmium tetroxide (O5O4 vapours was superior to the conventional preparation methods. Which involve critical point drying. Mycelium exposed to vapours from a solution of 2% O5O4 for 24 h at ca. 20°C retained its turger and natural structures. Best results were achived when young mycelium was used. whereas old mycelium always collapased, irrespective of the fixation method used.Use of this method for fixation of Aspergillus spp. is therefore preferable to convennonal methods which are laborious. time‐consuming and often interfere with the natural habit of structures. It may also prove usefull with other fungal structures.
Serological Comparison of Antigens Related to Local Virus and Bacterial Infections and Aspecific Stresses in Tobacco Leaves
Authors: El‐Kady S. , Gáborjányi R. , Király Z. 
Published: May 2008

AbstractTwo “new” precipitin bands (antigens) detected by the immunodiffusion test were demon strated in leaf extracts of tobacco inoculated with tobacco mosaic virus (TMV), Pseudomonas tabaci or treated with mercuric chloride, sodium azide or sodium hypochlorite. One of the precipitin bands was stronger, than the other, These antigens were also detected in the upper, non‐infected leaves of tobacco plants when the lower leaves were locally stressed (necrotized) either by TMV or by chemical injury. The “new” antigens formed in the upper leaves were detected even if the TMV‐inoculated lower leaves were removed one day after inoculation. The “new” antigens were identical both in the lower and upper leaves and their induction was independent from the stress whether pathogenic or chemical.A coincidence exists between the appearance of “new” antigens and acquired resistance, but this does not mean necessarily a cause‐and‐effect relationship between the two phenomena. Our experiments indicate that the induction of the synthesis of “new” stress proteins in tobacco is aspecific and the proteins formed are related to the aspecific stress itself rather than to pathogenesis.
Effect of Flavin Inhibitors on Photoactivation of Oospores of Phytophthora cactorum
Authors: Banihashemi Z. , Mitchell J. E. 
Published: May 2008

AbstractWhen dark‐grown mature oospores of Phytophthora cactorum were activated to germinate by exposure to 5 uW cm‐2nm‐1 of fluorescent light at 20–22°C in the presence of certain flavin inhibitors such as KI, salicylhydroxamic acid and phenylaceric acid at 40. 1. and 0.1 mM respectively, photoactivation and hence subsequent germination of oospores were inhibited without appreciable irreversible effect on oospore viability. Likewise, when applied during the light period, NaN3 and KCN at 1 mM reduced photoactivation but had a minimal effect on dark reactions. Diphenylamine, an inhibitor of certain carotenoids, had no effect on photoactivation of oospores. The data suggest that the photoreceptor pigment for activation of oospore germination is a flavin.
Suppression of Damping off on Pepper Caused by Pythium ultimum Trow and Rhizoctonia solani Kühn by Some New Antagonists in Comparison with Trichoderma harzianum Rifai
Authors: Turhan Gürhan , Turhan Kutsi 
Published: May 2008

AbstractPot experiments were designed to evaluate the efficacy of Streptomyces nobilis, S. ochraceiscleroticus, Neocosmospora vasmfecta var. Africana and Acrophialophora levis isolates in reducing the damping‐off on pepper in comparison with a strong mycoparasitic isolate of Trichoderma harzianum.Two pathogenic and five potential antagonistic isolates were grown seperately m flasks containing a mixture of sand‐perlite‐corn meal and potato‐sucrose broth for 4 weeks. Soil infestation was achieved by mixing these stock cultures separately into the pot soils. Disease incidence was expressed as the percentages of dead seedlings in each pot and the protective values of the antagonists were calculated according to Abbott formula.Results indicated that all of the five test isolates have provided the seedhngs with protection of statistical value against Pythium uhimum and Rhizocionia solani reducing disease incidence between 28.14 to 79.14 % and 22.76 to 66.83 %, respectively. However, T. harzianum isolate proved to be the least effective antagonist against both pathogens.
In vitro Culture of Grapevine Infected by Closterovirus Type III*
Authors: Barba M. , Cupidi A. , Faggioli F. 
Published: May 2008

AbstractHerbaceous cuttings collected in autumn from a closterovirus type III infected grapevine plant (cv. Merlot) were micropropagated in vitro.Results showed thai cultured plants did not present any leaf symptoms even if they grow slower than healthy control plants by a ratio of about 1/2.The virus concentration, as estimated by electron microscopy, was found constant when observed fortnightly over a period of 75 days. The number of particles was about 30 times higher than in viral preparations obtained from infected material collected in the field.
Effects of Bean Leaf Age on Pathogenicity by Botrytis fabae
Authors: Heilbronn Jacqueline , Harrison J. G. 
Published: May 2008

AbstractLeaves from field bean plants grown out of doors were inoculated with conidia of B. fabae immediately after detaching from stems. The oldest leaves developed more lesions than youngest ones, although they were not chlorotic. On intact plants at high humidities, established lesions on young leaves increased in size at only half the rate of those on old. but still green leaves. Seven days after inoculation a higher proportion of lesions on old leaves bore conidia than those on young leaves, but leaf age had no significant effect on numbers of conidia per mm2 of lesion area.Young leaflets from bean plants grown in a controlled environment or in the field challenged with β. cinerea accumulated more phytoalexins than did old ones.
Studies of Didytmella bryoniae (Auersw.) Rehm: Development in the Host
Authors: de Neergaard Eigil 
Published: May 2008

AbstractGrowing hyphae of Didymella bryoniae (Auersw.) Rehm are found in the stem tissue of cucumber, and the fungus can colonize nearly all types of tissue. The presence of the pathogen in the lignified elements suggests a spread of the disease up and down from the site of primary infection, even when the stem is strongly decomposed. The fungus dtsplays hyphal dimorphism in the infected tissue and a remarkable feature is stromatic‐like structures in the host tissue close to fruiting bodies. Staining reveals no histological host reaction to fungal penetration of cell walls. The pathogen is characterized by the early development of its sexual stage.
Storage of Wheat FoliagePrior to Enzyme‐Linked Immunosorbent Assay for Detection of Wheat Soil‐Borne Mosaic Virus
Authors: Armitage C. R. , Hunger R. M. , Sherwood J. L. , Weeks D. L. 
Published: May 2008

AbstractPlant samples, collected at various times during a growing season, are frequently stored prior to evaluating resistance to wheat soil‐borne mosaic virus (WSBMV) by enzyme‐linked immunosorbent assay (ELISA). Leaves of winter wheat cvs Sage and Vona, showing symptoms of WSBMV infection, were cut in half along the midrib. Each half was either: 1) refrigerated at 4 °C, 2) frozen at −20 °C, 3) frozen at –70 °C, or 4) desiccated with CaCl2. Relative virus antigen titres were evaluated for individual leaf halves by ELISA. ELISA absorbance means from desiccated leaf halves were consistently higher than absorbance means from corresponding leaf halves that had been frozen. This distinction suggests that virus antigen decreases during freezing but is retained during chemical desiccation. All 4 methods of storage were found to be suitable for short‐term storage prior to qualitative evaluations by ELISA, but chemical desiccation was the superior method for long‐term storage and for storage of foliar samples prior to quantitative evaluations by ELISA.
Monoclonal Antibodies for Detection and Serotyping of Cucumber Mosaic Virus
Authors: Haase Anita , Richter J. , Rabenstein F. 
Published: May 2008

AbstractTwo monoclonal antibodies (MAbs) to cucumber mosaic virus (CMV) were selected from a panel of MAbs for use in the direct DAS (double antibody sandwich)‐ELISA. Two different test procedures were developed: an ELISA with polyclonal and monoclonal antibodies (mixed ELISA) for the routine detection of CMV and a MAb‐ELISA with two MAbs directed against different epitopes for the specific detection of the N serotype which is prevalent in GDR. The conventional two‐step incubation of plates precoated with IgG was compared with simultaneous incubation of test sample and labelled antibody (one‐step incubation). The mixed ELISA proved to be more sensitive than the direct DAS‐ELISA with polyclonal antisera in detecting CMV in crude sap of infected plants. On the other hand, the MAb‐ELISA could be used for serotyping of CMV isolates which is important in epidemiological investigations and in resistance breeding. Both the two‐step and the one‐step procedures gave similar results with some advantages of the latter procedure. One‐step incubation is not only time‐saving but seems to be also more sensitive with regard to the detection limit. However, care must be taken to circumvent the hook‐effect occurring at high virus concentrations.
Nonspecific Phytotoxic Effects of Sirodesmins on Host and Nonhost Plants of Leptosphaeria maculans
Authors: Badawy H. M. A. , Hoppe H. H. 
Published: May 2008

AbstractSirodesmin PL, deacetylsirodesmin PL and sirodesmin C were isolated from cultures of an aggressive strain of Leptosphaeria maculans, purified by thin layer and column chromatography, and tested on leaves and roots of 14 host and non‐host plants of the pathogen. The sirodesmins showed no host‐specificity. However, various plant species developed symptoms of different severities. In both bioassay systems deacetylsirodesmin PL had a lower phytotoxicity than sirodesmin PL and sirodes‐min C. Our results show that sirodesmins belong to the non‐host‐specific phytotoxins.
Elimination of Apple Mosaic Virus and Raspberry Bushy Dwarf Virus from Infected Red Raspberry (Rubus idaeus L.) by Tissue Culture
Authors: Theiler‐Hedtrich R. , Baumann Gisela 
Published: May 2008

AbstractExperiments with ApMV infected ‘Malling Landmark’ and RBDV infected ‘Schamp;önemannamp;’ and ‘Trentamp;’ plants were carried out to evaluatea) the dependence of virus eradication on explant size and mass propagation.b) the reliability of results of ELISA tests on in vitro plantlets.With ApMV a correlation between virus elimination and explant size was observed, whereas with RBDV even plantlets from the smallest established explants were still infected. With ApMV, in vitro multiplication for three subsequent subcultures did not lead to further virus elimination, with RBDV this was observed in two cases.ELISA test results for both viruses, ApMV and RBDV, were identical when small in vitro plantlets, long‐term stored plants, or potted plants from the same origin were tested, indicating that virus tests are possible with very young plant material and can be used to select virus‐free plants in vitro. Tissue culture permits long‐term storage of plant viruses. It is also suitable tor plant virus propagation and could be a useful aid in plant virus purification.For commercial multiplication only virus‐indexed plant material should be used for establishment and further propagation in vitro.
Partial Characterization of Artichoke Virus M
Authors: Di Franco A. , Gallitelli D. , Vovlas C. , Martelli G. P. 
Published: May 2008

AbstractA virus with filamentous particles 697 nm in length was isolated from artichoke plants in Southern Italy and identified as a new possible member of Carlavirus group, for which the name artichoke virus M (AVM) is suggested.AVM could not be transmitted by sap inoculation to herbaceous hosts and was always present in artichoke in mixed infections with other viruses. Virus particles had a buoyant density in CsCl of 1.31 g × cm−3 and contained a single species of nucleic acid with an apparent size of 7.5 Kb and a single coat protein species with a mol. wt of 31,000. The virus was distantly related serologically to carnation latent and poplar mosaic carlaviruses but not to other members of the group including the recently described artichoke latent S carlavirus. Cytological alterations consisted of complex cytoplasmic inclusions composed of deranged organelles, lipid droplets and accumulations of membranes.
The Extracellular Acidic and Basic Pathogenesis‐Related Proteins of Soybean Induced by Viral Infection
Authors: Roggero P. , Pennazio S. 
Published: May 2008

AbstractSeventeen major host‐encoded pathogenesis related (PR)‐proteins have been found in intercellular fluids of necrotic virus‐infected soybean leaves. None of them was present in fluids of healthy controls. By native and SDS‐denaturing polyacrylamide gel electrophoresis, ten major acidic PR‐proteins have been identified and classified on the basis of their molecular weight in three groups: group 1 included four proteins of 16–17 Kd; group 2, three proteins of 26 Kd; group 3, three proteins of 32 Kd. Seven PR‐proteins were basic, and were classified in three groups: group 1 included three proteins of 16 Kd; group 2, one protein of 23 Kd; group 3, three proteins of 32 Kd.As found for tobacco and potato, soybean PR‐protein patterns show high number of acidic and basic proteins.
Untersuchungen zum Wirkungsspektrum und zur Wirkungsweise zweier quarternärer Ammoniumverbindungen gegenüber phytopathogenen Viren
Authors: Bockholt S. , Hellwald K. H. , Buchenauer H. 
Published: May 2008

Abstract Investigation of the influence of two quarternary ammonium compounds on some viruses and their mode of action The inhibitory effect of benzyl‐dimethyl‐hexadecylammoniumchloride (BDHA) and N‐benzyl‐N‐dodecyl‐N‐bis (2‐liydroxyethyl)‐ammoniumchloride (BDBA) to various phytopathogenic viruses was studied. These substances were selected from 10 other quarternary ammonium compounds tested. They showed an inhibitory activity against BMV‐, CMV‐, CMoV‐, PVX‐, TMV‐ and TNV‐infections.Studies on the mode of action of BDBA and BDHA in the virus‐host‐system TMV/Nicotiana tabacum var. Xanthi nc. revealed that the compounds exhibited besides a pre‐infectional also a post‐infectional inhibitory activity. Further, it has been shown that they display a direct inhibitory effect on TMV. The longlasting pre‐infectional effect of the compounds resulted not only in a reduction of formation of local lesions, but also in a smaller size and a lower antigene content of the lesions. An antiviral activity was also detected in non‐treated younger leaves of treated plants 10–14 days after treatment. This phenomenon was linked with the appearance of some new proteins in the intercellular fluids.
Erwinia amylovora Infection of Hawthorn Blossom
Authors: Wilson M. , Sigee D. C. , Epton H. A. S. 
Published: May 2008

AbstractStamens of freshly opened flowers of hawthorn were inoculated with E;. amylovora and the development of blossom infection was monitored by viable bacterial counts and light and electron microscopy. Some bacterial multiplication occurred on the anther surface, over the dehiscence zone and over the junctions ot the anther‐wall cells. bacteria invaded the anther loculc, via the ruptured dehiscence zone, and possibly also vid the stomata surrounding the filament insertion. bacteria within the locule multiplied rapidk with estimated doubling‐times which were longer than those derived from in vitro data. Pollen grains Irom infected anthers were found to be heavily eontaminated with bacteria.The invasion of anther tissue, with the production of contaminated pollen, may be important epidemiologieally both as a phase of rapid bacterial multiplication and in the insect‐mediated spread of this disease.
Distribution of Streptomycin Resistant Strains of Erwinia amylovora in Egypt during 1988
Authors: El‐Goorani M. A. , El‐Kasheir H. M. A. , Shoeib Alia A. , Hassanein Ferial M. 
Published: May 2008

AbstractA survey of the occurrence of strains of Erwinia amylovora resistant to streptomycin in certain Egyptian pear orchards was earned out during April and May 1988. Twenty‐two isolates out of 604 isolates collected from 11 orchards showed resistance to streptomycin. All the streptomycin resistant (Strr) strains isolated in the present work were resistant to high levels of streptomycin with minimal inhibitory concentrations ranging from 1000 to 3000 μg/ml. The occurrence of Strr strains in Egypt is still limited and the population of resistant strains was at relatively low level. However, such occurrence of E. amylovora with resistance to streptomycin is a potentially serious situation.
Biology and Control of Entyloma eryngii (Cda.) de By., the Cause of a Leaf Spot Disease on the Blue Thistle (Eryngium alpinum L.)
Authors: Rüegg J. 
Published: May 2008

AbstractThe blue thistle (Eryngium alpinum L.), an indigenous perennial flower of the alps, is grown in mountainous regions of south‐eastern Switzerland. The commercial value of the fresh cut flowers can be seriously reduced due to a leaf spot disease caused by the smut fungus Entyloma eryngii (Cda.) de By. The fungus produces thick walled chlamydospores and two types of conidia. The disease appears to be favoured by cool‐rainy weather and a dense foilage resulting in long periods of leaf wetness. Control of the disease can be achieved with the protective fungicide mancozeb or even more efficiently with the systemic ergosterol‐biosynthesis‐inhibiting fungicides cyproconazole and difenoconazole.
Maintenance of MLOs (Mycoplasma‐like Organisms) on Populus alba Micropropagation
Authors: Cousin Marie‐Thérèse , Roux Jacqueline , Millet Nadège , Michel Marie‐France 
Published: May 2008

Abstract Populus alba plantlet micropropagation has been used for maintaining MLOs more than three years in samples collected from infected trees in Paris. Symptoms were observed on plantlets obtained from subcultures of the apical, middle and basal parts of the stems, and from the roots. Fluorescent microscopy failed to detect MLOs in the apical part of the plantlets and showed that they increased near the roots. Electron microscopy confirmed their presence. Some root sieve tubes were completely packed with MLOs. The sensitivity of the two methods used, subculturing and microscopy, for detection of MLOs is discussed. The symptoms remained for one year in plants regenerated from diseased plantlets and grown in the greenhouse. Then they started to disappear.