bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phytophthora infestans in Poland from 1987–1989; Nuclear DNA Content, Mating Type Distribution and Response to Metalaxyl
Authors: Therrien C. D. , Ritch D. L. , Sujkowski L. S. , Spielman L. J. , Fry W. E. , Daggett S. S. , Sim J. H. , Tooley P. W. 
Published: May 2008

AbstractIsolates of Phytophthora infestans were collected from all potato growing regions of Poland during the blight seasons of 1987—1989. All 1987 isolates were of Al mating type and were sensitive to metalaxyl. In 1988 and 1989, 46.5 % and 55.3 % of the isolates were sensitive to metalaxyl, respectively. The percentage of highly resistant (R) isolates increased from 25.6 % in 1988 to 39.5 % in 1989; however the percentage of intermediately resistant (I) isolates decreased during that period from 27.9 % to 5.3 %. A significant association was observed between the A1 compatibility type and metalaxyl resistance. The A2 mating type first appeared in 1988, and its frequency increased from 4.7 % of the population in 1988 to 47.6 % in 1989. Coincident with this change in mating type frequency, changes in ploidy levels of isolates were observed. Whereas 3 % of the 1988 isolates were diploid, 90 % of the 1989 A2 isolates and 28.6 % of the 1989 Al isolates were diploid. The approximate 1:1 ratio of the two mating types encountered in 1989, and the predominance of diploidy, indicates that the Polish population of P. infestans has the potential to become sexual.
Differential Accumulation of Translatable mRNA Species During a Specific Host‐pathogen Interaction Between Puccinia recondita tritici and Triticum aestivum
Authors: Heinz Ruth A. , Del Vas Mariana , Moratinos Laura C. , Favret Ewald A. , Hopp H. Esteban 
Published: May 2008

AbstractThe time‐course of mRNA induction in specific cultivar‐race combinations was examined using a criss‐cross interaction system consisting of nearly isogenic lines of wheat (Sinvalocho M.A. and Gamma 1R) and genetically related pathogenic races of leaf rust Puccinia recondita f. sp. tritici. Infection stimulated the differential accumulation of mRNA species, identified by in vitro translation, after only three days of inoculation with rust spores. Comparisons of different host‐pathogen combinations showed polypeptide pattern changes likely to be associated with gene‐for‐gene relationships. At least two specific mRNAs which code for polypeptide bands of 34 and 24 kDa are associated with the compatible interaction mediated by genes A1,/A2 from Gamma 1R wheat line and virulence gene pt/p2 of rust race FO1. Comparisons made using a mutant clone of rust, which elicits an inverse criss‐cross relationship with the same wheat lines, are consistent with the proposed specificity of the detected changes.In addition, two wheat mRNAs (coding for polypeptide bands of 20.5 and 32.5 kDa) were elicited by infection with rust race FO1 regardless the plant genotype or reaction type. A cDNA clone involved in this kind of race specific induction has been isolated.
Xanthine Oxidase Activity in the Susceptible and Hypersensitive Responses of Tobacco Leaves to Tobacco Mosaic Virus Infection
Authors: Montalbini P. 
Published: May 2008

AbstractA superoxide‐producing xanthine oxidoreductase was isolated and quantified after polyacrylamide disc gel electrophoresis of tobacco leaf extracts. The results obtained indicate that, like uricase activity, a slight increase in tobacco xanthine oxidase activity takes place in the susceptible interaction with tobacco mosaic virus (TMV). In contrast, out of three hypersensitive tobacco cultivars tested, only two showed the same slight increase m activity during the late stage of hypersensitive response.Allopurinol [4‐hydroxypyrazolo(3,4‐d)pyrimidine] a specific and potent in vitro and in vivo inhibitor of xanthine oxidoreductase, applied to tobacco plants by root absorption, starting about 8 days before the inoculation, did not affect the hypersensitive response but weakened the hypersensitivity‐linked virus localization and promoted the movement of a certain amount of TMV particles and/or virus related material from necrotic lesions which induced systemic necrotic symptoms in uninoculated leaves. However, due to the inefficacy of allopurinol in preventing necrotic lesion development, all results are consistent with the hypothesis that xanthine oxidoreductase, the first enzyme in purine oxidative degradation, plays only a secondary role during induction of primary hypersensitive cell death in TMV infected tobacco leaves.
Preliminary Investigations on the Rusts of Perennial Ryegrass in Central Italy
Authors: Cappelli C. , Marte M. , Paul V. 
Published: May 2008

AbstractThe results of a four‐year investigation carried out in Central Italy on the occurrence of perennial ryegrass rusts from 1989—92 are reported. The crown rust (Puccinia coronata) was the most frequently recorded in the surveyed are while P. graminis was only occasionally detected. The causal agents were identified by the morphological criteria proposed by CUMMINS (1971).A single‐pustule isolate of P. coronata was used to test the resistance of seven ryegrass cultivars under greenhouse conditions. Two cultivars, ‘Artal’ and ‘Score’, proved resistant to the fungus isolate while the remaining (‘Elka’, ‘Patora’, ‘Pleno’, ‘Sisu’ and ‘Vejo’) were high susceptible.
Inhibition of Some Rot Fungi Polygalacturonases by Allium cepa L. and Allium porrum L. Extracts
Authors: Favaron F. , Castiglioni C. , Lenna P. Di 
Published: May 2008

AbstractExtracts of Allium cepa and A. porrum‐ contain factors that inhibit to various extents polygalacturonases (PGs) produced in vitro by Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium moniliforme, Phoma terrestris, Sclerotium cepivorum, Macrophomina phaseolina, Didymella bryoniae andPhoma lycopersici. The PG inhibition rank changed using leek or onion extract. The inhibition factors are possibly proteins, do not present particular specificity and act against PGs of fungi pathogens and non pathogens for these plant species.
Agrobacterium tumehciens After in vivo Inoculation of Potato (Sohnum tuberosum L.) (Scanning Electron Microscopy)
Authors: Starkbauerova Zuzana , ŠRobárová Antonia 
Published: May 2008

AbstractFive weeks after the in vivo inoculation of potatoes (Solanum tuberosum L.) with Agrobacterium. tumefaciens strain B6S3, bacteria were found in the non‐differentiated cells of tumors (formed from xylem parenchyma or other living cells), in xylem cells at the site of inoculation, as well as in xylem cells of the adjacent stem.Bacteria were attached by fibrillar aggregates to the tumor cell walls. They were also attached to a fibrillar mass which arose from agrobacteria connected to this mass in the tumor. Agrobacteria, singly or in pairs, were attached to an electron dense formation (possibly bacterial extracellular polysaccharides) found both inside the xylem cells of the stem adjacent to the tumor and at the site of inoculation. Some A. tumefaciens cells were attached by means of a pedestal‐like structure at the inoculation site.A possible function of the different means of attachment of A. tumefaciens in both nontransformed plant cells and tumors is discussed.
The Inhibition of Fungal Growth in Resistant Cotton Plants Infected by Fusarium oxysporum f. sp. vasinfectum
Authors: Shi J. , Mueller W. C. , Beckman C. H. 
Published: May 2008

AbstractThe vascular colonization of cotton plants by Fusarium oxysporum f. sp. vasinfectum was determined by examining growth of the fungus from free‐hand cross sections taken from 0 to six days after inoculation at various distances above the points of root inoculation. Fungal spread in both longitudinal and lateral directions in the susceptible cultivar Rowden was evident four days after inoculation, whereas fungal spread in the resistant cultivar Seabrook Sea Island was restricted. The quantity of viable fungus in infected tissues was determined from macerated tissues plated on Czapek‐ Dox agar. The colony counts declined within six days after inoculation in resistant Seabrook Sea Island, but not in susceptible Rowden, implying that an inhibition of fungal growth in vascular tissues occurred in resistant Seabrook Sea Island. This inhibition could contribute to the restriction of fungal spread and thus be a factor in the resistance of cotton plants to F. oxysporum f. sp. vasinfectum.
Use of Random Amplified Polymorphic DNA (RAPD) Analysis and Genetic Fingerprinting to Differentiate Isolates of Race O, C and T of Bipolaris maydis
Authors: Nicholson P. , Rezanoor H. N. , Su H. 
Published: May 2008

AbstractIsolates of three races of Bipolaris maydis from China (races O, C and T) were compared using two techniques. Random Amplified Polymorphic DNA (RAPD) analysis using 24 primers indicated that race O and C isolates were more similar to one another than to the race T isolate. Twenty of the primers produced RAPD profiles that were similar for the race O and C isolates but differed for the race T isolate (four primers did not amplify products in any of the isolates). Four primers produced profiles which differed for all three races and two of these (A‐09 and B‐18) clearly differentiated the race O and race C isolates. Genetic fingerprinting of B. maydis using M13 DNA as a probe differentiated race O and C isolates from the race T with all four restriction enzymes used. Furthermore, when DNA was digested with Hind III, the hybridization profiles of the race O and C isolates differed from one another.
Interaction hôte‐parasiteSolanum gilo(Raddli)Stemphylium floridanum(Hannon et Weber). Relation entre teneur en acide chlorogénique foliaire et résistance au pathogène
Authors: Clerivet A. , Macheix J. J. 
Published: May 2008

AbstractPhenolic profile ofSolanum giloleaves was investigated after incubation withStemphylium floridanumculture filtrates. The amount of chlorogenic acid, largely dominant, was in correlation with foliar resistance either by a high constitutive level in some leaves (apical leaves of productive plants) or by a fast increase induced in other leaves by fungus elicitors (youngest leaves of plants nursery). An additional role of other identified phenolic compounds was also proposed so that a sufficient resistance level was conferred toS.giloleaves.
Studies on the Biology of Polymyxa betae, the Vector of Beet Necrotic Yellow Vein Virus
Authors: Ahm H. D , Buchenauer H. 
Published: May 2008

AbstractThe development of Polymyxa betae within the roots of a sugar beet variety susceptible to Rhizomania was observed in hydroponic culture over a period of 10 days. Light microscope studies showed that at an average temperature of 20 °C the life cycle of the fungus, containing beet necrotic yellow vein virus (BNYW), was completed within 10 days. A change from the multiplication phase to the survival phase of P. betae became evident. At the beginning of the life cycle the fungus produced mainly zoospores whereas at a later stage plasmodia developed into resting spores. Zoospore density in the nutrient solution reached a maximum between the 5th and 7th day after inoculation and then declined to the initial concentration. The number of zoospores attached to the root surface increased progressively at 48 h intervals, correlated with a parallel increase in BNYW‐content of the roots. Light‐ and fluorescence microscopy revealed that zoospores of P. betae often attach near the point of release and do not move very long distances. In addition it became evident that zoospores may attach to the thallus wall inside the zoosporangium that they have developed in.
Morphology of a New Pathotype ofBipolaris zeicola(Stout) Shoemaker
Authors: Levic Jelena , Pencic Viktorija 
Published: May 2008

AbstractConidia of a new pathotype ofBipolaris zeicola(Stout) Shoemaker, which causesHelminthosporiumcorn leaf spot (HCLS) on inbreds derived from B73, are morphologically atypical on potato dextrose agar (PDA). The average conidial length on PDA (31.9 μm) is half that on naturally infected leaf (65.2 μm). Conidiogenuous cells terminally and subterminally located on short conidiophores produce new conidia which behave as initial conidia, i.e. they immediately elongate or germinate. Sometimes, they appear in chains. Based on conidial morphology on leaf materials and on wheat straw agar (WSA), the investigated fungus was identified asB. zeicola.
Barley Yellow Dwarf Virus Multiplication and Host Plant Tolerance in Durum Wheat
Authors: Cheour F. , Comeau A. , Asselin A. 
Published: May 2008

AbstractA Canadian PAV‐like isolate of barley yellow dwarf virus (BYDV) was used to infect durum wheat (Triticum durum) cultivars previously identified in field trials involving artificial inoculation as highly sensitive (12 IDSN74), slightly tolerant (La Dulce), and relatively tolerant (Boohai and 12 IDSN227) to BYDV. The cultivars were inoculated in the greenhouse as seedlings, and indexed for virus accumulation by enzyme‐linked immunosorbent assay (ELISA) at various intervals between 3 and 60 days thereafter. Mean ELISA values were somewhat consistent with tolerance levels for 4 durum wheat cultivars, but the use of ELISA to screen for BYDV resistance in durum wheat is not practical. The magnitude of the difference between sensitive and tolerant cultivars for the mean ELISA value is not high enough, and it may be necessary to average readings between 3 and 60 days after inoculation to obtain somewhat meaningful ELISA data. The effect of vector aphid numbers on virus titre and aerial biomass in the sensitive durum wheat cv. Karim was also evaluated. There was no significant effect on virus content in a preliminary trial, but a second trial revealed that more viruliferous aphids per plant resulted in higher ELISA values. Infestation with 32 or 50 viruliferous Rhopalosiphum padi per plant depressed biomass yield below the level observed with 1–10 aphids per plant.
Development of Ramularia Leaf Spot on Sugar Beet as Influenced by Temperature and the Age of the Host Plant
Authors: Hestbjerg H. , Wolffhechel H. , Dissjng H. 
Published: May 2008

AbstractA method of inoculating sugar beet plants (Beta vulgaris L.) with Ramularia beticola Faut. & Lamb, is described. Following inoculation, disease development in relation to temperature and plant age was studied for more than a month. The incubation period was 18 days at 10°C compared to 14 days at 17°C. At 25°C no symptoms appeared. Both temperature and plant age significantly influenced disease level and rate of disease development. Plants incubated at 17°C were more severely diseased 33 days after inoculation than plants incubated at 10°C. Young plants (3 weeks at inoculation) Were more susceptible than older plants (5 and 8 weeks at inoculatson) under growth chamber conditions. In the field, symptoms of Ramularia leaf spot appear relatively late in the season and young leaves are rarely attacked. The inconsistency of these observations is discussed.
ACTG‐Toxins Produced by a Strain of Alternaria altemata That Does Not Originate From Citrus Species
Authors: Liebermann B. , Ellinger R. , Ihn W. 
Published: May 2008

AbstractAGTG‐toxins designated as host‐specific toxins were isolated at first from a pathotype of Alternaria alternata attacking Citrus species. A strain of Alternaria alternata isolated from Brassica sinensis in Central Germany and improved to a high tentoxin content, also produces two ACTG‐toxins. It is doubtful, therefore, if both substances can be denoted as host‐specific toxins.
Diversity in Pathogenicity to Tobacco and in Elicitin Production among Isolates of Phytophthora parasitica
Authors: Bonnet Ph. , Lacourt I. , Venard P. , Ricci P. 
Published: May 2008

AbstractThe pathogenicity to tobacco of a large set of Phytophthora parasitica isolates has been assessed using several procedures: root inoculation of young plants, leaf inoculation on detached disks and stem inoculation of decapitated plants, with or without healing. Analysing various aspects of the plantpathogen interaction with this array of tests led to the discrimination between three groups of isolates. In the isolates from hosts other than tobacco, none was truly pathogenic to tobacco, and all but one produced parasiticein, a proteinaceous elicitor of the elicitin family which induces a hypersensitive‐like response in tobacco. Isolates producing parasiticein in vitro induced necrotic fleks on the leaves upon inoculation of roots orof, freshly wounded stems. Most tobacco isolates, including all the highly virulent ones, were characterized by a lack of elicitin production. However, those collected in Australia and Zimbabwe differed in that they exhibited reduced virulence, induced leaf, necrotic flecks and produced parasiticein. The incidence of elicitin production on virulence and the significance of two types of tobacco‐pathogenic strains for tobacco pathology are discussed.
Characterization and Plasmid Profile of Xanthomonas campestris pv. Glycines from Maharashtra, India
Authors: Sharma A. , Syed A. N. , Nair P. M. 
Published: May 2008

Abstract Xanthomonas campestris pv. glycines, (Xcg), the causative agent of the bacterial pustule disease of soybean was isolated and characterized. On susceptible soybean the pathogenic isolates displayed characteristic chlorotic lesions around the site of infection within 48 h of inoculation. The pathogenic isolates were found to contain two cryptic plasmids. A smaller plasmid of 1.5 kb and a larger one of size about 25 kb. SDS‐PAGE profile of the soluble proteins of the pathogenic isolatess, howed a different pattern compared to that of the non‐pathogenic isolates.
Le Paraquat, un Outil pour la Révélation Rapide d'Infections Fongiques Latentes et de Champignons Endophytes
Authors: Gindrat D. , Pezet R. 
Published: May 2008

AbstractParaquat: a tool for the quick development of latent fungal infections and endophytic fungi.Detached winter wheat leaves without any symptom of fungal infection were thoroughly washed, surface desinfected, treated with paraquat (0.03–0.32% a.i.) and incubated on nutrient agar or in moist chambers under sterile conditions. Microscopic examinations showed that hypae and yeast cells emerged from several stomata within 48–72 h after treatment. Fungal colonies developed on agar within the same period of time. More than 27 filamentous fungal genera and yeasts were identified during a wheat cropin healthy, green leaves. Non‐treated leaves showed very few early emergences of fungi from stomata, but senescent leaves eventually yielded several fungal taxa observed after paraquat treatment. Similar observations were made on non‐detached wheat leaves, and on detached sugarbeet leaves. Paraquat also induced development ofFusariumspp. from detached healthy winter wheat ears before or after heading. In grape berries, paraquat induced the development of latent infections ofBotrytis cinerea, a few days after treatment.The usefulness of paraquat for the detection of endophytes and for the diagnosis of early and latent fungal infections in plants, and the possible involvement of endophytes in tissue senescence are discussed.
Bacterial Antagonists to Verticillium dahliae Kleb.
Authors: Berg G. , Ballin G. 
Published: May 2008

AbstractBacteria were isolated from the rhizosphere of Verticillium dahliae hosts and from environments. A total of 1394 bacterial isolates were screened for their ability to inhibit in vitro the growth of the phytopathogenic fungi V. dahliae; 15% (203 of the isolates) showed antifungal effects. Seventeen isolates were selected and determined for further investigations, seven different species were identified. Several of the bacterial species listed, e.g. Erwinia herbicola, Pseudomonas chlororaphis, Pseudomonas paucimobilis and Xanthomonas maltophilia have not been reported previously as bacterial antagonists of V. dahliae. Bacillus subtilis, Pseudomonas fluorescens and Xanthomonas maltophilia are strong antagonists. We proved that lytic enzymes and siderophores are involved in the inhibition of growth. Ultrastructural and morphological changes were induced in Verticillium dahliae by the antagonistic bacteria.
Cytopathology and Ultrastructure of Some African Isolates of Maize Streak and Sugarcane Streak Viruses
Authors: Ammar E. D. 
Published: May 2008

AbstractSamples of maize leaves naturally infected with maize streak virus (MSV) from Malawi and South Africa, as well as sugarcane leaves naturally infected with sugarcane streak virus (SSV) from Egypt, were examined by light (LM) and transmission electron, microscopy (TEM). Intranuclear inclusions, detectable by both methods, were found mainly in mesophyll and bundle sheath cells, and less frequently in vascular parenchyma and immature phloem cells. At higher TEM magnifications, these inclusions consisted, of crystalline or noncrystalline aggregates of isometric geminivirus–like particles (VLP) that occurred either singly or in geminate arrays. Cytopathological changes in these cells were confined to the nuclei, which were usually larger than normal, with peripheral chromatin and nucleoli. The nuclear envelope of some inclusion–containing nuclei was ruptured, and occasionally a crystal of VLP was found in the cytoplasm of cells in which no intact nuclei were detected. No differences in cytopathology were found between MSV and SSV, or between the two MSV isolates examined.
Studies on Taxonomic Relationships of Mycoplasma–like Organisms by Southern blot Analysis
Authors: Schneider B. , Seemüller E. 
Published: May 2008

AbstractChromosomal DNA fragments from the mycoplasma‐like organisms (MLOs) associated with American aster yellows, apple proliferation, clover phyllody, and vaccinium witches' broom were cloned. Several MLO‐specific fragments from each of these four isolates and a sequence from the 16S rRNA gene of an aster yellows MLO were used in Southern blot hybridizations to investigate the taxonomic relationships of 26 pathologically and geographically diverse MLOs. These MLOs were divided into four categories according to the symptoms induced in periwinkle. Genotypically, these isolates represented four groups (16S RFLP groups) of a classification based on restriction fragment length polymorphisms (RFLP) and sequencing data of the 16S rRNA gene. Probes from three isolates of one symptom category hybridized with isolates from all symptom categories. This result indicates that classification of MLOs by symptomatology does often not coincide with genetic relationships. The hybridization results confirmed the findings, of the 16S RFLP classification that most MLOs from herbaceous plants, especially those inducing virescence in periwinkle, are interrelated. These isolates, which were assigned to one 16S RFLP group, could be further differentiated in this study. Itcould be shown that aster yellows, clover phyllody, stolbur, and safflower phyllody and sandal spike are caused by distinct MLOs. The MLOs associated with apple proliferation, vaccinium witches' broom, and witches' broom of lime as well as two isolatesfrom, stone fruits could also be recognized as distinct organisms.
Separation and Degradative Action of Polygalacturonase Isozymes Produced by Colletotrichum musae
Authors: Stanley M. S. , Brown A. E. 
Published: May 2008

AbstractPolygalacturonase (PG) produced by Colletotrichum musae in liquid culture on banana pectic substances as the sole carbon source resolved into five distinct isozymes, with isoelectric points ranging between pl 4.8‐6.5. All five isozymes were detected in banana tissues rotted by C. musae.Isozymes PG I (90 kD) and PG II (36 kD) were separated from PG III, IV and V (60‐70 kD) by gel filtration on a Superose 12 column. PG III, IV and V were resolved on a hydrophobic column (Alkyl Superose, HR 5/5) by changing gradients of 0.1 M sodium acetate buffer (pH 5.0). PG II, III, IV and V had endo‐activity and PG I had exoactivity.