bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mycoparasitism of Pythium ultimum by Antagonistic Binucleate Rhizoctonia Isolates in Agar Media and on Capsicum Seeds
Authors: Siwek K. , Harris A. R. , Scott E. S. 
Published: May 2008

AbstractHyphal interactions between two antagonistic binucleate Rhizoctonia isolates (BNR) and the seedling dampingoff pathogen, Pythium ultimum var. sporangiiferum, were observed by both light‐and scanning electron microscopy (SEM), on agar media and on capsicum seeds in sterilized potting mix. Both BNR isolates displayed similar mycoparasitic behaviour towards P. u. sporangiiferum on agar media. This included parallel growth along the pathogen hyphae, formation of hook‐shaped hyphal tips and coils on the surface of P. u. sporangiiferum hyphae and penetration and growth within pathogen structures. Disruption of cytoplasmic streaming and disorganisation of pathogen cytoplasm were also observed. SEM observations revealed alterations in P. u. sporangiiferum cell wall structure and the presence of penetration holes apparently due to digestion by the BNR. P. u. sporangiiferum was also parasitised by both BNR isolates on capsicum seed coats, with parallel growth, hook formation and coils commonly observed. The above observations indicated that mycoparasitism is a possible mode of action of BNR against P. u. sporangiiferum.
Use of a Colonization‐Deficient Strain of Escherichia coli in Strain Combinations for Enhanced Biocontrol of Cucumber Seedling Diseases
Authors: Roberts D. P. , Dery P. D. , Mao W. , Hebbar P. K. 
Published: May 2008

AbstractSeed treatments containing combinations of Escherichia coli S17R1 and Burkholderia cepacia Bc‐B provided significantly greater (P ≤ 0.05) suppression of cucumber seedling pathogens in a field soil naturally infested with Pythium and Fusarium spp. than seeds treated individually with strains Bc‐B, S17R1, or Enterobacter cloacae 501R3. Although strain S17R1 had no effect on disease severity when applied alone and did not colonize cucumber rhizosphere, it enhanced the biocontrol effectiveness of strain Bc‐B.
Identification and Characterization of an Italian Isolate of Pear Blister Canker Viroid
Authors: Loreti S. , Faggioli F. , Barba M. 
Published: May 2008

AbstractA small RNA with the structural property characteristic of viroids has been isolated from a pear plant (P8) showing superficial cracks or splits on the bark of the secondary branches and horizontal deep bark splits on the trunk.Polyacrylamide gel electrophoresis analysis of the P8 isolate revealed that the viroid had the same electrophoretic mobility as pear blister canker viroid (PBCVd). P8 RNA reacted in molecular hybridization assays with the specific PBCVd cRNA probe, and its reverse transcript polymerase chain reaction amplified fragment was the same size as the amplified fragment of PBCVd.Sequence analysis of the P8 isolate revealed only five changes in its primary structure when compared with the standard PBCVd isolate P2098T, Four of these changes were present also in P47A and P1914T PBCVd isolates previously characterized in Spain, The viroid associated with P8 pear can thus be considered a PBCVd isolate. This is the first report of PBCVd in a pear orchard in Italy.
Role of Extracellular Polysaccharide (EPS) Slime of Plant Pathogenic Bacteria in Protecting Cells to Reactive Oxygen Species
Authors: Király Z. , El‐Zahaby H. M. , Klement Z. 
Published: May 2008

Abstract Pseudomonas syringae pv. phaseolicola, a phytopathogenic bacterium, seemed very sensitive in planta to the adverse action of reactive oxygen species (ROS) produced by two chemical systems. The disease symptoms in host plants were also suppressed by ROS. Several other plant pathogenic bacteria (P. syringae pv. pisi, Erwinia amylovora, Xanthomonas campestris pv. pelargonii) as well as P. fluorescens were also sensitive in vitro to the inhibiting or killinig action of ROS. It was shown that O2 and H2O2 were produced in our two chemical systems and were involved in the killing action. OH’however was not involved in the adverse action on bacteria of the ROS. Superoxide dismutase and catalase were able to reverse the killing action of ROS. When the EPS slime around bacteria was removed by washing and centrifuging the cells, bacteria were more sensitive to ROS. However, when the cells of EPS‐ mutants were washed and centrifuged, their sensitivity to the killing action of ROS did not change because the lack of slime around the mutant cells.The EPS‐ Tn5 mutants of P. syringae pv. phaseolicola and the natural EPS‐ mutant of E. amylovora were more sensitive to ROS than the wild type strains. These results support the idea that the EPS slime protects bacteria from ROS (O‐2 and H2O2).
Inhibition of Polygalacturonase Activity Produced by Leptosphaeria maculans with Stem Extracts of Canola, and the Relationship of Inhibition to Resistance
Authors: Annis S. L. , Goodwin P. H. 
Published: May 2008

Abstract Leptosphaeria maculans, the causal agent of blackleg of canola, produces polygalacturonases during infection. Stem extracts of spring and winter canola cultivars contained a water‐soluble inhibitor of the polygalacturonase activity of L. maculans. The polygalacturonase inhibitor material had different characteristics dependent upon the cultivar. Some canola cultivars had a polygalacturonase inhibitory compound(s) which was heat liable, low molecular weight and required divalent cations, and other cultivars had a heat stable, low molecular weight compound(s). The cultivar Maluka had a unique polygalacturonase inhibitory compound(s) that was heat labile, low molecular weight and did not need divalent cations. The level of the polygalacturonase inhibitory activity in the stem extracts was significantly related to the resistance of the cultivars to L. maculans as measured by the rate of lesion elongation, but was less related to the rate of stem girdling. The significant correlation between levels of polygalacturonase inhibitor activity and stem resistance in canola cultivars indicates that polygalacturonase inhibitors may be involved in the resistance of stems to blackleg. The two quantitative measures of stem resistance, rate of lesion elongation and rate of stem girdling, were significantly correlated to cotyledon resistance and to each other.
Poinsettia Leaf Curl, a New Disease Caused by a Geminivirus
Authors: Tsai M.‐C. , Liu C.‐S. , Su H.‐J. 
Published: May 2008

AbstractA serious disorder of unknown aetiology was found on the poinsettia cv. Angelica, a recent introduction to Taiwan. The symptoms of downward leaf curling and vein enation were similar to those of leaf curl disease on tobacco. The causal agent of the disease was transmitted to healthy plants of‘Angelica’poinsettia, common poinsettia and tobacco by whiteflies. Twinned particles measuring 16‐18 × 30‐32 nm were detected in a purified preparation obtained from diseased leaf tissues of‘Angelica’poinsettia, indicating that the disease is caused by a geminivirus. An earlier introduction of common poinsettias also showed mild leaf curl symptoms under natural condition. When the causal agent of this disease was transmitted to healthy‘Angelica’poinsettia plants by whiteflies or bud grafting, these plants also developed severe leaf curl symptoms, indicating that the disease is not a new introduction to Taiwan.
Immunoenzymatic Detection of PCR Products for the Identification of Phytoplasmas in Plants
Authors: Poggi Pollini C. , Giunchedi L. , Bissani R. 
Published: May 2008

AbstractPolymerase chain reaction (PCR, with universal and specific primers designed on rRNA genes) provides a rapid, reliable method of diagnosing phytoplasmas (formerly mycoplasma‐like organisms) in plants. However, to attain a better identification of these prokaryotes, it is often necessary to digest the PCR products with restriction endonucleases or to hybridize them with specific probes. The present study compared routine procedures for detecting PCR products against a new system, PCRELISA (Boehringer Mannheim), which enables immunoenzymatic detection of PCR products. The results show that this new system provides fast and highly sensitive detection of several phytoplasmas associated with certain trees and shrubs. Optimization of all parameters involved in the PCR‐ELISA procedure and its advantages are reported and discussed.
Penetration and Infection Process of Phyllactinia corylea on Mulberry Leaf Causing Powdery Mildew — I. Asexual Stage
Authors: Kumar Vinvwt , Babu A. M. , Sharma D. D. , Datta R. K. 
Published: May 2008

AbstractSurface morphology of conidia of Phyllactinia corylea (Pers.) Karst., its germination, penetration of hyphal branches and the infection process on mulberry leaf are described, under scanning electron microscope. Surface pf the clavate. hyaline conidium is ornamented with evenly distributed spine‐like protrusions. The conidia germinate 4 h after inoculation, producing a single germ tube mostly from a little behind the distal end of the conidium. The hyphae soon produce special branches. stomatopodia. which enter the leaf through stomata. The stomatopodia are produced singly or in pairs, and one or two stomatopodia enter in a stoma. The branched superficial hyphae forms a mycelial mass within 72 h after inoculation. The disease becomes apparent at conidial stage. The conidiophores were straight at early stages, but appeared spirally coiled when the conidia were mature. which may aid for conidial detachment.ZusammenfassungPenetration und Infektionsverlauf von Phyllactinia corylea, Erreger des Echten Mehltaus der Maulbeere, auf Maulbeerblättern (I. Ungeschlechtliches Stadium)Beschrieben werden die Morphologie der Oberfläche von Konidien des Pilzes Phyllactinia corylea (Pers.) Karst. sowie ihre Keimung. die Penetration von Hyphen in die Maulbeerblätter und der anschließende Infektionsverlauf. Die Untersuchungen erfolgten mit Hilfe der Rasterelektronenmikroskopie. Die Oberflächen der keulenförmigen. hyalinen Konidien sind gleichmäßig mit dornenähnlichen Ausslülpungen besetzt. Die Konidien keimen 4 h nach der Inokulation und bilden kurz hinter ihrem distalen Ende einen unverzweigten Keimschlauch. Nach kurzer Zeit bilden die Hyphen besondere Verzweigungen (Stomatopodien). welche durch die Stomata in die Blätter eindringen. Die Stomatopodien werden einzeln oder in Paaren gebildet, und jeweils ein oder zwei Stomatopodien treten in ein Stoma ein. Die verzweigten Hyphen an der Oberfläche bilden innerhalb von 72 h nach der Inokulation ein dichtes Myzel. Die krankheit wird im Konidienstadium bemerkbar. Die Konidiophoren sind zunächst gerade. zur Zeit der Konidienreife jedoch spiralig gewunden, was die Ablösung der Konidien erleichtern könnte.
Characteristics of Monoclonal Antibodies to Lucerne Transient Streak Sobemovirus and Their Use in Epitope Localization
Authors: Sehgal O. P. , Sinha R. C. 
Published: May 2008

AbstractMurine monoclonal antibodies (mAbs) to lucerne transient streak sobemovirus (LTSV) were used as probes for examining the virion capsid organization. A panel of nine mAbs from approximately 100 hybridomas were chosen for this study. All of these mAbs interacted effectively with sites on intact capsid and isolated coat protein sub‐units (i.e. metatopes) in ELISA and Western blots. Only one of these mAbs reacted with virions in gel diffusion test producing a visible precipitin band. Competitive binding assays showed that these mAbs recognized the same or very similar metatopes. None of the mAbs neutralized LTSV virion infectivity but rabbit polyclonal antibodies drastically reduced infectivity. Treatment of virions with EDTA (swollen LTSV). protein crosslinking reagents or sodium dodecyl sulphate caused no detectable alterations in their reactivities with these mAbs, The binding sites for monoclonal and polyclonal antibodies were located on denatured 5.5 kDa fragments resulting from partial trypsinization of LTSV coat protein and 8 kDa fragments formed with chymopapain proteolysis. These results indicate that these LTSV epitopes are of linear (or sequential) configuration and are located on the exposed, structurally stable domain of the virion capsid.
HydroxyproUne‐rich Glycoprotein Accumulation in TMV‐infected Tobacco Showing Systemic Acquired Resistance to Powdery Mildew
Authors: Raggi V. 
Published: May 2008

AbstractTobacco cv. Havana 425, with systemic‐acquired resistance (SAR) to an otherwise compatible Erysiphe cicho‐racearum DC. race after TMV infection, was infected with TMV basaily (4th and 5th leaves) and the hydroxyproline‐rich glycoproteins (HRGPs) were determined in two experiments (experiment 1 and experiment 2) by analysing cell wall hydroxyproline (Hyp) in the 6th leaf. In basal TMV infected plants Hyp content (μmol‐1 FW) was greater than in controls in both experiments: the increase was significant at all times except 16 days after TMV inoculation in experiment 1; the pool of data of experiment 2 was also significantly increased. In TMV protected +E. cichoracearum challenged leaves compared to untreated controls significant increases in Hyp were also noted between the pools of data in both experiments. No differences were found between Hyp content in protected compared to protected + challenged leaves in both experiments. These results show accumulation of HRGPs in Havana tobacco associated with TMV infection and SAR activation against E, cichoracearum. The accumulation appears to be due to the inducer, since no further increase was detected in protected leaves after challenging.
Botryosphaeria dothidea and Other Fungi Associated with Excoriose and Dieback of Grapevines in Portugal
Authors: Phillips A. J. L. 
Published: May 2008

AbstractIn a study of fungi associated with symptoms of excoriose in Portugal, the most prevalent ones were found to be Botryosphaeria dothidea and Phomopsis viticola. In artificial inoculations, these two fungi infected grapevines causing dark lesions on the shoots and bud mortality. They were re‐isolated from the shoot lesions and necrotic buds. Two further species of Botryosphaeria, namely B. obtusa and B. stevensii, were also isolated and they caused small lesions on wounded shoots but did not infect unwounded shoots. B. dothidea was also isolated from grapevines with a dieback of the trunk. These isolates were more virulent on young shoots and one‐year‐old canes than the ones from grapevines with excoriose.
The Role of Hyalesthes obsoletus (Hemiptera: Cixiidae) in the Occurrence of Bois noir of Grapevines in France
Authors: Sforza R. , Clair D. , Daire X. , Larrue J. , Boudon‐Padieu E. 
Published: May 2008

AbstractAn epidemiological study on a grapevine yellows disease called bois noir was carried out for 3 years in the Rhone valley (France). This yellows is caused by a stolbur type phytoplasma. Vectors and alternative host plants were searched, and the inoculation period was determined. Detection of stolbur phytoplasma in insects and plants was obtained using primers STOLl1 f2/r1. In addition, a nested polymerase chain reaction (PCR) was used with primers P1/P7 and fU5/rU3 for detection in stolbur‐infected plants with low titre. Several thousand insects were captured and species of Hemiptera were listed. Fourteen wild or reared Hemiptera species were used in transmission trials. Thirty‐four wild species were monitored for phytoplasma DNA by PCR. A planthopper. Hvalesthes obsoletus Sign., tested positive for stolbur at a level of 28% (98,/343) in 1995 and 38% (205,529) in 1996. In 1995, two leafhoppers, Mocydia crocea (178) and Euscelis tineolatus (2/309), were infected at a much lower ratio. Successful experimental transmission to grapevine, periwinkle and thorn apple was only obtained with H. obsoletus. Among wild plant species, hoary cress (Cardaria draba L.), bindweed (Convolvulus arvensis L.), sweet cherry (Prunus sp.), plum (Prunus domestica L), lilac (Syringa vulgaris L.), fig tree (Ficus carica L.) and elm (Ulmus sp.) were shown to be stolbur infected and hoary cress was identified as a new host plant for H. obsoletus in France. The role of some fallow lands close to vineyards as sites where the inoculum of stolbur phytoplasma was maintained in insect vector and reservoir plants, is discussed. The natural inoculation period to grapevine was shown to extend from June to August, corresponding to the adult activity of H. obsoletus. Together with the close relationships of the phytoplasmas involved in vergilbungskrankheit, a German grapevine disease, and bois noir. The results of this study suggest that the two yellows are very close.
Susceptibility of Barleys to Bipolaris sorokiniana Seedling Blight Determined by Disease Scoring and Electrolyte Leakage
Authors: Wtsniewska H. , Wakulinaski W. , Chelkowski J. 
Published: May 2008

AbstractSpring (14) and winter (8) barley cultivars were examined for seedling susceptibility (root and coleoptile) to Bipolaris sorokiniana infection under a controlled environment. High susceptibility of all cultivars to root rot was observed, both in winter and spring genotypes, Coleoptile infection on average, was about three times lower than root disease score. Significant membrane injury up to 35% of maximum electrolyte leakage was observed on the 7th day after inoculation. In only 3 cultivars were the membrane injuries low‐on the level of 3–6% and related with low coleoptile infection. Resistance of the barley cultivars to B. sorokiniana was not related with their resistance to Fusarium cutmorum
In Vitro Effect of Plant Leaf Extracts on Mycelial Growth and Sclerotial Germination of Sclerotium cepivorum
Authors: Pinto C. M. F. , Maffia L. A. , Casali V. W. D. , Cardoso A. A. 
Published: May 2008

AbstractThe effects of leaf extracts of Brachiaria humidicola, Crotalaria paulina. Eucalyptus citriodora. and Brassica oleracea var. capitata on mycelial growth and sclerotial germination of Sclerotium cepivorum were evaluated in vitro. Water extracts of leaves had little effect on either growth or germination. However, acetone‐water leaf extracts usually had the greatest inhibitory effects. Acetone‐water extracts reduced mycelial growth more than sclerotial germination. Leaf extracts of E. citriodora at 1000 and 10000p.p.m. in acetone‐water completely inhibited mycelial growth and sclerotial germination of S. cepivorum. Thus, this extract is potentially useful for the control of garlic white rot. and its effect will be evaluated under field conditions.
Involvement of the Antioxidative System in Tomato Response to Fusaric Acid Treatment
Authors: Kuźniak E. , Patykowski J. , Urbanek H. 
Published: May 2008

AbstractChanges in O2‐ and H2O2 generation as well as superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase activities were examined in fusaric acid‐treated tomato leaves. Fusaric acid application resulted in a lasting activation of O2‐ and H2O2 production. Within the first day after toxin application the H2O2 scavenging enzymes: catalase and ascorbate peroxidase showed a strong activity decrease followed by a gradual recovery to the control level after 2 and 3 days. By contrast fusaric acid markedly stimulated peroxidase activity measured with guaiacol as well as ferulic and coumaric acids, and syringaldazine. The maximum activity increase, coinciding with the highest H2O2 level, was about two‐fold and 5.5‐fold for phenolic acids and syringaldazine, respectively. The results obtained are discussed in the light of the data on the role of activated oxygen species and enzymes of their metabolism in plant defence.
Water Stress and the Development of Cankers by Diplodia mutila on Quercus robur
Authors: Ragazzi A. , Moricca S. , Dellavalle I. 
Published: May 2008

AbstractSome experiments were conducted (in duplicate) to determine the effects of the osmotic potential on the growth of Diplodia mutila, and the effects of the pre‐dawn water potential on the development of cankers by D. mutila on Quercus robur. Mycelium of D. mutila was grown on liquid medium enriched with various amounts of polyethylene glycol so as to give osmotic potential values of ‐0.35, ‐1.18, ‐1.75, ‐3.00 and ‐3.98 MPa. At the two lowest MPa values (‐3.00 and ‐3.98 MPa) D. mutila growth was slower in relation to the fresh weight and the dry weight of the mycelium. To determine the pre‐dawn water potential 30 3‐year‐old Q. robur seedlings were inoculated with D. mutila mycelium. Water‐stressed seedlings had lower pre‐dawn water potential values (MPa ‐2.92) and longer cankers than the unstressed seedlings (MPa ‐0.79). It is concluded that Q. robur, a highly hygrophilous oak, suffers from water stress to such an extent that its structural and chemical defences are overcome and the seedlings are seriously damaged. A similar situation is observed in nature, where frequent and prolonged droughts may induce states of water stress that account for the spread and the incidence of D. mutila in Italy.
Expression of transketolase‐like 1 (TKTL1) and p‐Akt correlates with the progression of cervical neoplasia
Authors: Kohrenhagen Nico , Voelker Hans U. , Schmidt Melanie , Kapp Michaela , Krockenberger Matthias , Frambach Torsten , Dietl Johanees , Kammerer Ulrike 
Published: May 2008

AbstractAim:  It is supposed that increased glycolysis is crucial for the energy supply during tumor progression. Unfortunately, the relevance of glycolysis in cervical neoplasia is unknown, but what is certain is the fact that cervical cancer shows a high expression of glucose membrane transporters, which are necessary for glucose uptake as an energy source. Transketolase‐like enzyme 1 (TKTL1) and the oncogene p‐Akt have been described to play an important role in glycolysis during tumorigenesis. Thus, we were interested in their expression in cervical tissue.Methods:  We examined the expression of TKTL1 and p‐Akt in 80 formalin‐fixed, paraffin‐embedded cervical specimens: 20 benign cervical tissues, 20 low‐grade squamous intraepithelial lesions, 20 high‐grade intraepithelial lesions, and 20 invasive squamous cell carcinomas (ISCC).Results:  Immunhistochemical analyses revealed that the intensity of the expression of TKTL1 and p‐Akt increases significantly with an increase in the histopathological grade of cervical tissues.Conclusion:  The results suggest that both TKTL1 and p‐Akt play an important role in the progression of cervical neoplasia, which may be due to their impact on glycolysis.