bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developpement de Leveillula taurica en Fonction des Facteurs Climatiques et Sensibilité de Capsicum annuumà Differents Stades Végétatifs
Authors: Diop‐Bruckler Marguerite 
Published: May 2008

AbstractInfluence of environmental factors on the development of L. taurica on pepper genotypes To our knowledge, the effects of certain environmental factors, as well as those of host genotype on the development of Leveillula taurica on pepper have not been extensively investigated. To study effects of the above factors on the development of this parasite, two Capsicum genotypes (‘Yolo Wonder' and ‘line 815’) have been tested and compared under different light and relative humidity conditions. In vitro, optimal light intensity for spore germination was situated between 20 and 80 μE/m2/s, and for the growth of germ tubes it was 20 μE/m2/s. In vivo, under continous darkness during 20 days, the different organs of the hosts were only slightly affected. Under light conditions, during 20 days after inoculation, the highest infection level on leaves was observed at 20 μE/m2/s, (60 % of leaves) while with the cotyledons it was observed between 20–80 μE/m2/s.Effects of relative humidity on the development of this parasite were also studied on ‘Yolo Wonder’ and ‘line 815′. With relative humidity below 50 %, 60 % of ‘Yolo Wonder’ plants and 33 % of ‘line 815’ were infected. Under conditions of saturated relative humidity, the level of infection was the inverse, i. e. 13 and 55 %, respectively.Moreover, ‘Yolo Wonder’ plants were found more or less susceptible to infection with L. taurica during their different development stages. At the cotyledon stage all plants were infected. After this stage, up to flowering, susceptibility depended on the physiological age of the leaves. First leaves (older leaves) were not infected, while young ones near the apex became progressively susceptible.
Der Einfluβ von Sauerstoff und UV‐Licht auf die Konidienproduktion von Pseudocercospordh herpotrichoides (Fron) Deighton, Merkmale zur Morphologie des Erregers und dessen Nachweis an Dikotyledonen
Authors: Gieffers W. , Paul V. H. , Ritter E. 
Published: May 2008

AbstractThe influence of oxygen and U.V.‐light for the conidia production of Pseudocercosporella herpotrichoides (Fron) Deighton, morphological characters of the pathogen and its evidence on dicotyledons The particular importance of oxygen was detected for sporulation of Pseudocercosporella herpotrichoides. Four methods have been elaborated for different sporulation requirements of P. herpotrichoides. Only for a few populations three methods were necessary for rapid conidia production. The best method for maximum conidia production consisted of the following conditions: a constant temperature of 10 °C, permanent moistening with liquid water for inoculated materials, oxygen and U. V.‐light. Infected stalks and leaves from cereals were sporulating after 3 days and inoculated materials after 3 to 6 days. Maximum conidia production was reached after 7 to 21 days. Good sporulation was obtained also under cool temperatures, permanent moisture and air and light conditions in the open. But the conidia production was stronger under controlled conditions.Different isolates of P. herpotrichoides were compared with respect to morphological characteristics of hyphae, mycelia and conidia.Thus far observed only on cereals and grasses. P. herpotrichoides was found also on dicotyledons by the sporulation method described. This evidence has been obtained on an isolate of 00‐winter rape (Brassica napus, ssp. Oleifera). Moreover P. herpotrichoides has been found on chlorotic and necrotic leaves of rape, flesh‐coloured trefoil (Trifolium incarnatum), madia‐oil plant (Linum usitatissimum L.) and lady's‐thistle (Silyhum marianum [L.] Gaertn.) in high frequency. P. capsellae was found on necrotic leaves of chickweed (Stellaria media).
Bacillus thuringiensis ‐ A New Perspective for an Induced Protection to Coffee Leaf Rust*
Authors: Roveratni Dagmar S. , Teixeira Ana Regina R. , Moraes Walkyria B. C. 
Published: May 2008

AbstractSusceptible coffee plants (Coffea arabica cv. ‘Mundo Novo’) treated with a suspension of Bacillus thuringiensis or with three of commercial products (Thuricide HD, Bactimos and Bactospeine PM) of B. thurngiensis were protected against a later inoculation with Hemileia vastatrix, the causal agent of coffee leaf rust. Thuricide HD was effective at concentrations from 5 to 20 mg/ml; at this concentration, protection reached 90 %, lasted for at least 5 weeks, and was systemic. Induced resistance was determined by the reduction of the average number of lesions per leaf in treated leaves when compared with non‐treated controls. A decrease in lesion size as well as a delay in sporulation time were also observed in protected plants treated with Thuricide HD.
ELISA Detection of Odontoglossum Ringspot Virus in Mature Plants and Protocorms of Cymbidium Orchids: Potential Solutions to Problems of Sample Preparation Time and Low Virus Concentration
Authors: Arunasalam G. , Pearson M. N. 
Published: May 2008

AbstractThe ability to detect Odontoglossum ringspot virus (ORSV) released from the cut surfaces of leaf discs by ELISA was examined. Results indicate that ORSV from leaf discs can be detected but that multiple discs are necessary to obtain reliable detection of low virus concentrations, ELISA of Cymbidium protocorms, known from immunosorbent electron microscopy to be infected with ORSV, frequently produced A435 values which would be considered either negative or marginally positive on the basis of commonly accepted statistical limits (i, e. 2 x mean, or mean + 3 x standard deviation). The comparison of paired samples, one of which had been pretteated with ORSV antiserum, improved the sensitivity of the test from 10 ng ml ‘’ of virus to 2 ng ml’.
Chlorate Sensitivity of Sclerotium bataticola Isolates from Different Hosts
Authors: Zazzerini A. , Tosi L. 
Published: May 2008

AbstractOur results indicate that it is impossible to characterize Isolates of Sclerotium bataticola Taub. [=Macrophamina phaseolina (Tassi) Goid.; Tiarosporella phaseolina (Tassi) Van der Aa] obtained from different plants (sunflower, sorghum, soybean and safflower) by using the chlorate sensitivity test. Indeed, strains isolated from the same species and from the same location reacted differently towards chlorate. The pathogenicity test proved the non‐existence of host specialization by the parasite.
Vector and Host‐Plant Relationships of the Leafhopper‐Borne Maize Yellow Stripe Virus
Authors: Ammar E. D. , Elnagar S. , Abul‐Ata A. E. , Sewify G. H. 
Published: May 2008

AbstractMaize yellow stripe virus (MYSV), associated with tenuivirus‐like filaments, is transmitted in a persistent manner by the leafhopper Cicadulina chinai. In this vector, MYSV acquisition and inoculation threshold times were 30 min each, latent period ranged from 4.5 to 8 days depending on temperature (14‐25 °C), and retention periods were as long as 27 days. Up to 26 % of C, chinai collected from maize fields in Giza, Egypt, during September and October 1985 were naturally infective with MYSV. Two symptom‐types (fine and coarse stripe) appeared on experimentally infected plants, usually on separate leaves of the same plant. However, these two symptom‐types could not be isolated on separate plants through transmission by single C. chinai leafhoppers. MYSV was transmitted by nymphs and adults of C. chinai from maize to maize, wheat and barley, and from wheat to maize plants. Up to 6 % of the wheat plants examined in Naga Hamadi (Southern Egypt) in February 1986, were naturally infected. It is suggested that wheat, barley and possibly graminaceous weeds may serve as winter hosts or reservoirs for MYSV and its leafhopper vector in Egypt.
Pathotypes of Peronospora viciae in Britain
Authors: Taylor P. N. , Lewis B. G. , Matthews P. 
Published: May 2008

AbstractFifty‐five isolates of Peronospora viciae from a wide range of locations in Britain were tested on 10 inbred lines of Pisum sativum. Reactions ranged from extreme resistance, where the pathogen failed to spread in the tissues and caused no macroscopic symptoms, to extreme susceptibility, where the pathogen spread extensively and sporulated abundantly. Based on two differential reactions, namely, symptomless resistance and all other more susceptible reactions, 22 groups of isolates were distinguishable. On the four most discriminating differential lines, eleven groups of isolates were distinguished; these are designated UK Pathotypes, (UKP) 1–11, and the four lines nominated as standard differential hosts.
Methods of Inoculation of Faba Bean Plants with Sclerotinia sclerotiorum
Authors: Lithourgidis A. S. , Tzavella‐Klonari K. , Roupakias D. G. 
Published: May 2008

AbstractDifferent organic materials colonized by the fungus were applied, as an energy‐rich inoculum, on faba bean plants cv. Polycarpe in growth chamber experiments. The organic materials used were colonized pieces of celery stems, faba bean petioles, and carrot root, blocks of cultures on potato dextrose agar and pieces of sclerotia. The inoculum was left attached to the plant stems for 48 h. After removal of the inoculum the plants were scored for disease incidence and severity. It was found that colonized pieces of carrot root produced the most uniform disease incidence and severity.
Effect of Growth Stage and Initial Inoculum Level on Leaf Rust Development and Yield Loss Caused by Puccinia recondita f. sp. tritici
Authors: Subba Rao K. V. , Snow J. P. , Berggren G. T. 
Published: May 2008

AbstractThe effects of the combinations of leaf rust inoculation at different growth stages and initial inoculum levels on leaf rust development and yield of winter wheat cultivars, McNair 1003 and Coker 762 were evaluated. Disease onset stage and initial inoculum level affected the rate of leaf rust development and shape of the disease progress curves in both cultivars. Epidemics with common onset stages and different initial inoculum levels differed in area under the disease progress curve (AUDPC). Leaf rust epidemics initiated at Feeke's growth stages 5, 7, and 10 reduced yield in both cultivars. Leaf rust epidemics initiated early with high inoculum levels had the greatest deleterious effect on yield. Maximum losses due to leaf rust were 30–40 %. Yield loss was directly related to AUDPC when the AUDPC varied from 500 to 1700 in McNair 1003 and from 250 to 1700 in Coker 762. Yield reduction was mainly due to reduction in grain weight.
Suppression of Root Rot on Peas, Beans and Beetroots Caused by Pythium ultimum and Rhizoctonia solani through the Amendment of Growing Media with Composted Organic Household Waste
Authors: Schüler C. , Biala J. , Bruns C. , Gottschall R. , Ahlers S. , Vogtmann H. 
Published: May 2008

AbstractIn pot experiments under controlled environmental conditions, composted organic household waste showed a suppression of soilborne plant pathogens. The addition of 8 %, 10 % and 30 % compost to the potting material which was artificially infested with Pythium ultimum or Rhizoctonia solani considerably reduced the incidence of disease in different varieties of host plants. It became evident that the degree of protection provided by compost depends upon the amount of compost added and upon the vulnerability of the host plant to infection. In an experiment using increasing levels of inoculum, the compost proved suppressive to the pathogen even under extreme disease conditions. This suppressive effect was still evident in compost which had been stored for prolonged periods.
The Occurrence of Cell Wall Appositions in Flag Leaves of Spring Wheats, Susceptible and Partially Resistant to Wheat Leaf Rust
Authors: Jacobs Th. 
Published: May 2008

AbstractIn two experiments, the presence of cell wall appositions in flag leaves of spring wheat genotypes susceptible and partially resistant to wheat leaf rust was studied. More cell wall appositions were observed near aborted infection structures than in estabhshed colonies. There was not a marked difference in the number of cell wall appositions per colony between susceptible and partially resistant genotypes. More cell wall appositions per unit area colony were present in partially resistant genotypes. It was concluded that the low number of cell wall appositions could not be responsible for the observed difference in colony size between susceptible and partially resistant genotypes. Partial resistance in wheat to wheat leaf rust can be divided into two phases. The first phase is pre‐haustorial and results in a reduction of the number of colonizing infection structures. In the second phase a post‐haustorial retardation of fungal growth rate occurs. The latter appears to be the more important phase.
Isolation of Proteins Related to the β‐Lectin from Potato which Bind to Hyphal Wall Components of Phytophthora infestans
Authors: Furuichi N. , Suzuki J. 
Published: May 2008

AbstractProteins from potato cells which recognize fungal cell wall components of Phytophthora infestans were isolated after passage of a potato homogenate through an affinity column which contained bound fungal cell wall components. Bound potato proteins were eluted with NN′‐diacetylchitobiose, and fractionated by SDS‐polyaciylamide gel electrophoresis. Eluted proteins from cv. Yukijiro (R1‐gene) and cv. Irish Cobbler (r‐gene) had similar profiles and the same apparent Mr, 66, 58 and 41.5 kD and other proteins with lower molecular weight.Only the 41.5 kD and lower molecular weight proteins reaeted with polyclonal antibodies against the β‐lectin from the R1 cultivar, Rishiri.The surfaces of protoplasts from cvs Yukijiro and Irish Cobbler also reacted with the antibodies to the lectin. Treatment of potato protoplasts with hyphal cell wall components of P. infestans caused cytoplasmic aggregation, a response characteristic of the hypersensitive reaction. Oligomers of N‐acetyl glucosamine reduced the ability of fungal cell wall components to cause this cytoplasmic aggregation. These results suggest that binding between fungal cell wall eomponents and certain potato proteins is sensitive to N‐acetylglucosamine, and may play a role in the hypersensitive reaction.
Ultrastructure at the Host‐Parasite Interface of Phytophthora capsici in Roots and Stems of Capsicum annuum
Authors: Hwang ByungKook , Kim WoonBong , Kim WooKap 
Published: May 2008

AbstractThe infecting hyphae of Phytophthora capsici grew intercellularly in infected tissues of roots and stems of pepper (Capsicum annuum). The vascular tissues were not markedly disorganized even when heavily infected. Intercellularly growing hyphae penetrated the host cells by forming haustorium‐like bodies. The consistent features of ultrastructural changes in infected tissues of pepper roots and stems were degeneration of cell organelles and dissolution of host cell walls. The cytoplasm detached from the cell wall aggregated abundantly around some haustorium‐like bodies or the penetration sites of fungal hyphae. The host cell walls were palely stained, thinned and swollen, possibly being biochemically altered by the action of fungal macerating enzymes. Electron‐dense, wall‐like material was apposed on the outer wall of xylem vessel contacted by fungal hyphae. The infecting hyphae were also surrounded by granular, dark‐staining cytoplasm. Characteristics of host cell responses to the invading P. capsici were the deposition of papilla‐like material on host cell walls next to hyphae and the encasement of haustorium‐like bodies with wall appositions.
Correlations between Accumulation of Dianthramides, Dianthalexin and Unknown Compounds, and Partial Resistance to Fusarium oxysporum f. sp. dianthi in Eleven Carnation Cultivars
Authors: Baayen R. P. , Niemann G. J. 
Published: May 2008

AbstractThe accumulation of dianthramides, dianthalexin and other phenolic compounds in carnation cells at different times before and after inoculation of plants with Fusarium oxysporum f. sp. dianthi, and the development of wilt symptoms were compared for eleven carnation cultivars. Untreated and water‐treated controls contained only a little acetone‐extractable phenolics. Upon inoculation with F. oxysporum f. sp dianthi, all cultivars accumulated the same range of phenolic compounds, including several dianthramides and dianthalexin, but in different proportions. The total amount of accumulated phenolic compounds per fresh material weight of the extracted stem segments could not be related to the disease resistance level of the different cultivars. However, the accumulation of dianthramides and dianthalexin in the cultivars was positively correlated to resistance, while the accumulation of two other, as yet unidentified, compounds was inversely related to resistance.
Cell Wall Monosaccharide Composition and Muskmelon Resistance to Myrothecium roridum1
Authors: Kuti Joseph O. , Ng T. J , Gross K. C. , Moline H. E. 
Published: May 2008

Abstract In vitro growth of Myrothecium roridum, a pathogen of muskmelon (Cucumis melo L.), on media supplemented with eight cell wall‐related monosaccharides revealed that germination and germ tube elongation were enhanced in the presence of arabinose, galactose and glucose. Colony expansion of established mycelia of M. roridum was also enhanced by arabinose and glucose but inhibited by galactose, Non‐cellulosic neutral sugar analysis of fruit cell walls from muskmelon cultivars resistant or susceptible to M. roridum revealed that susceptible cultivars had consistently higher arabinosyl, galactosyl and glucosyl residue content than resistant cultivars, while a net loss of galaciosyl and arabinosyl residues occurred in cell walls of fruits between 20‐ and 27‐days post‐anthesis. M. roridum germinated more rapidly on isolated fruit cell walls from susceptible than resistant cultivars, but no correlation was found between cultivar resistance to M. roridum and inhibitin of fungal colony expansion on cell walls. Although factors affecting spore germination and mycelial growth of M. roridum, in vitro and in vivo, may differ, any factor that increases cell wall polysaccharide hydrolysis may contribute to ability of M. roridum to become established in immature fruit of muskmelon.
Effects of Nitrogen, Plant Density, Moisture Stress and Artificial Inoculation with Macrophomina phaseolina on Charcoal Rot Incidence in Grain Sorghum
Authors: Pande S. , Mughogho L. K. , Seetharama N. , Karunakar R. I. 
Published: May 2008

AbstractEffects of different levels of nitrogen, plant density, soil moisture stress and of anificial inoculation with Macrophomina phaseolina on charcoal rot incidence in grain sorghum were studied in a split‐split‐split field plot design. Nitrogen levels were applied to main plots; plant densities, moisture stresses and inoculations were replicated in sub, sub‐sub and sub‐sub‐sub plots. A gradient of soil moisture stress was created during grain filling by line‐source sprinkler irrigation. Analysis of variance indicated significant effects of moisture stress, plant density and their interactions on charcoal rot disease incidence as measured by piant lodging. Lodging increased linearly along the gradient of water supply suggesting a positive relationship between moisture stress and disease development. Lodging was also significantly (P < 0.01) and highly correlated with other charcoal rot disease parameters (soft stalk, number of nodes crossed, root infection and plant senescence). There were no significant differences (P < 0.05) in charcoal rot incidence among inoculation treatments. Lodging increased in both high nitrogen and high plant population treatments under moisture stress conditions.
African Cassava Mosaic Virus (ACMV): Stability of Purified Virus and Improved Conditions for its Detection in Cassava Leaves by ELISA
Authors: Kounounguissa Basfle R. , Givord Louise , Walter Bernard 
Published: May 2008

AbstractAfrican Cassava Mosaic Virus (ACMV) was purified by a method which allowed the separation of monomer from dimcr virus particles.Optimal conditions for storing purified virus to be used for immunization were determined by ELISA and inoculation on Nicotiana benthamiana. Purified virus could be stored without loss of infectivity and serological activity for more than 145 days at 4 °C or frozen at –20 °C, but not longer than 40 days in the presence of 50 % redistilled glycerol.Rabbit and chicken immunoglobulins were used to detect ACMV in cassava leaves by direct and indirect ELISA. To obtain the same absorbance values, it was necessary to use longer incubation times with the indirect method, but the virus detection end‐point m sap from infected plants was the same for the two methods (1/512).Conditions for improving virus detection tn cassava samples were determined. The virus was better detected when leaves from diseased plants were ground in 100 mM Tris‐HCl containing 1 % polyvinylpyrrolidone at pH 8.5 than in phosphate buffer. Plant inhibitors were the restricting factor in the detection of virus by ELISA, but this difficulty was avoided when leaves to be tested were harvested from the top of the cassava plants.
Evolution of Ethylene Production, ACC and Conjugated ACC Levels Accompanying Symptom Development in Tomato and Gynura aurantiaca DC Leaves Infected with Citrus Exocortis Viroid (CEV)
Authors: Bellés J. M. , Conejero V. 
Published: May 2008

AbstractEthylene production, ACC and Conjugated ACC levels as related to symptom development in leaves of tomato and Gynura aurantiaca infected with citrus exocortis viroid (CEV) were studied. In both hosts, the infection induced an increase in ethylene production and ACC levels and a strong accumulation of Conjugated ACC, Contrary to what happens with the stimulation of ethylene production and the enhancing of ACC content which maintain a steady level as leaves and their symptoms develop, conjugated ACC accumulation increased with the intensification of symptoms.
Relation Between the Chemical Structure and the Biological Activity of Hydroxystilbenes Against Botrytis cinerea
Authors: Pont V. , Pezet R. 
Published: May 2008

AbstractSome substituted trans‐hydroxystilbenes derived from pterostilbene and resveratrol were tested on germination, lethal effect and respiration of the conidia of Botrytis cinerea. These biological effects were related to the electronic character, to the lipophility of the substances and to their molecular volume. The products destroy the cellular membranes and could interfere with proteins of the electron transport systems.
Acrocalymma medicaginis and Phomopsis sp. as Causal Agents of Crown Rot of Lucerne in Australia
Authors: Nikandrow A. 
Published: May 2008

AbstractFungi associated with crown rotting were isolated from 3 year‐old lucerne plants growing in sandy and loam soils in an irrigated stand, declining in productivity, at Langhorne Creek, South Australia. The method of isolation markedly affected the range of species recovered. Fusarium spp. and Phomopsis sp. were isolated from washed and surface sterilized crowns, whereas a larger range of fungi, especially Acrocalymma medicaginis, was isolated from unwashed crowns. A. medicaginis was most frequently isolated from rotted tissue flecked with red, while a species of Phomopsis was the dominant fungus in whitish tissue containing zone lines, especially in crown branches. A. medicaginis and Phomopsis sp. caused crown rotting of mature, wounded lucerne plants at temperatures equivalent to summer conditions at Langhorne Creek. There was no evidence that Fusarium oxysporum or F. solani, two of the most frequently isolated species, were pathogens of mature lucerne plants.
Ultrastructural Study of Cytoplasmic Inclusions in Plants Infected with Potyviruses
Authors: Pisi A. , Bellardi M. G. 
Published: May 2008

AbstractThe ultrastructure of cell inclusions of different ornamental plants infected with several filamentous viruses of the potyviruses was studied at the transmission electron microscope. The plants examined were: Crocus sativus, Hyacinthus sp., Gladiolus sp., rhizomatous Iris, Muscari sp., Nerine bowdenii and Sparaxis sp. Differences in morphology of cylindrical inclusions have been used to separte the potyviruses in several subdivisions.