bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grassy‐shoot, a New Disease of Lemongrass Caused by Balansia sclerotica (Pat.) Hohnel
Authors: Janardhanan K. K. , Ahmad Absar , Gupta Motilal , Husain Akhtar 
Published: May 2008

AbstractA new disease of lemongrass (Cymbopogon flexuosus) caused by Balansia sclerotica was observed in India. The systemic infection induced deformed inflorescences and grassy‐shoot symptoms as a result of inhibition of growth of axillary buds and shortening of internodes. A number of ascostromata of the pathogen were produced on inflorescences of infected plants. Microscopic examination of infected host tissue revealed the presence of abundant endophytic mycelia. B. sclerotica was isolated from ascostromata and apical meristems of infected plants and its pathogenicity to lemongrass was experimentally established in three out of eighty‐two seedlings raised from seeds of inoculated plants. This report is one of the rare achievements in establishing the pathogenicity of fungal endophytes experimentally.
Leaf Spot of Alternanthera sessilis and Its Implications for Food Crops
Authors: Oladiran A. O. , Gana R. W. 
Published: May 2008

AbstractA leaf spot of Alternanthera sessilis caused by Fusarium pallidoroseum (syn. F. semitectum) is described. During pathogenicity tests, the fungus caused leaf spots of Amarantbus sp. Abelmoschus esculentus (okra), Celosia sp. and Sorghum bicolor. It also caused rots of tubers of Dioscorea rotundata, D. alata, Solanum tuberosum, corms of Colocasia esculenta, bulbs of Allium cepa and roots of Daucus carota when wounded. Unwounded tubers, corms, bulbs and roots of these named plants were not infected except roots of Daucus carota which disintegrated between 4 and 6 days after inoculation.
Evaluation of Certain Cowpea Genotypes for Partial Resistance to Powdery Mildew (Erysiphe polygoni)
Authors: Raju S. G. , Anilkumar T. B. , Chandrashekar M. 
Published: May 2008

AbstractPartial resistance to powdery mildew (Erysiphe polygoni) in twenty one cowpea cultivars was assessed over two to three seasons under field conditions. Mildew incidence was recorded as number of leaflets affected/plant and severity as AUDPC or infection rate using Gompertz transformation. Irrespective of the parameter used to measure mildew resistance or the season, mean response of cvs V‐105, V‐269, V‐276, V‐282 and V‐385 showed clear slow‐mildewing, while RC‐48, S‐488, TVX‐944‐02E, V‐27, V‐36 and V‐118 were rated as susceptible. Mildew resistance in some cultivars was negatively correlated with that for the leaf rust (Uromyces vignae).AUDPC was a more robust disease parameter than infection rate and showed a good correlation (r2= 0.79) with incidence.
The Use of Trichoderma koningii in the Control of Web Blight Disease Caused by Rhizoctonia solani in the Foliage of Cowpea (Vigna unguiculata)
Authors: Latunde‐Dada A. O. 
Published: May 2008

AbstractThe foliage of a field‐sown cowpea cultivar (IT82E‐60) was inoculated with an isolate of the aerial ecotype of Rhizoctonia solani and sprayed thereafter, at two frequencies, with a spore suspension of Trichoderma koningii. Although the antagonist restricted the spread of web blight disease the extent of disease reduction and the yield levels were significantly (P 0.05) higher in the plants sprayed twice weekly with T. koningii spore suspension. These levels of disease reduction and yield compared favourably with those obtained from inoculated cowpea plants protected with a fungicide mixture. The significance of these results is discussed in relation to investigations on the application of Trichoderma spp. in the biocontrol of disease of the phylloplane.
The Variability of Pyrenochaeta terrestris Isolates Based on Isozyme Polymorphism, Cultural Characteristics and Virulence on Differential Onion Breeding Lines
Authors: Ferreira J. F. , Bosland P. W. , Williams P. H. 
Published: May 2008

AbstractIsolates of Pyrenochaeta terrestris from South Africa and the United States of America were evaluated for pathogenicity, isozyme polymorphism and cultural characteristics. Isozyme polymorphism indicated that the isolates of this pathogen, even from the same field, are highly variable. Based on variability in the enzymes: alcohol dehydrogenase, aldolase, malate dehydrogenase and sorbitol dehydrogenase, the isolates could be divided into five electrophoretic types. The virulence of isolates to onion breeding lines resistant, moderately resistant and susceptible to pink root was variable and differentiation depended on the isolate used in the evaluation. The isolates showed extensive variation in both the ability to form setose pycnidia in culture and in the cultural pigmentation.
Identification and Characterization of Tobamoviruses Strains Infecting L‐resistant Genotypes of Peppers in France
Authors: Gebre‐Selassie Kahsay , Marchoux G. 
Published: May 2008

AbstractCharacterization of tobamovirus isolates collected from pepper crops in South East France has revealed the existance of several strains belonging to different viruses of the group. The biological and serological properties of three isolates (Vi76, Adam and Eve), selected as representative strains, have been studied. They have been compared with TMV and ToMV strains already isolated in our region as well as with other reference strains of ToMV‐D and TMV‐U1. They were also compared with other tobamovirus strains P11, P8 and P14, from the Netherlands, and PMMV‐W from Italy also isolated from pepper genotypes possessing the “L” gene for resistance to TMV and ToMV strains.According to biological and serological reactions, Vi76 is more related to ToMV than to TMV but it is not related to Adam and Eve which are more closely related to PMMV. On the basis of the interaction with the “L” gene for resistance in pepper genotypes we have found that the Adam and P8 strains belong to the P1‐2 pathotype and the Eve and P14 strains to the P1‐2‐3 pathotype and all the 4 strains belong to the PMMV‐W group.In France, there have been no reports of the isolation of the P11 strain which is distantly related to the Adam strain.
Histochemistry of Tobacco Mesophyll Cell Walls Pretreated with Bacterial Protein‐lipopolysaccharides
Authors: Minardi P. 
Published: May 2008

AbstractPrevention of hypersensitive confluent‐necrosis in tobacco mesophyll, caused by Pseudomonas syringae pv. aptata, and tolerance towards the incompatible bacterium are induced 48 h after intercellular injection of protein‐lipopolysaccharide complexes. Histochemical analysis and ultrastructural observations were carried out to determine whether there was an association between this tolerance state and cell wall alterations due to callose, lignin and/or suberin deposition either before or after challenge with the incompatible bacterium. No evidence was obtained for such wall alterations.
Isozyme Variation and Genetic Diversity of the European Barley Powdery Mildew Population
Authors: Koch G. , Köhler W. 
Published: May 2008

AbstractIsozyme and virulence analyses of Erysiphe graminis bordei were performed with samples collected from different sites from nearly all over Europe. Isozymes and unspecific proteins extracted from conidia were separated by starch gel electrophoresis and isoelectric focusing, respectively, and the resulting isozyme banding patterns were compared with the corresponding virulence data.One isozyme phenotype prevailed in all samples. Only 7.9% of 280 isolates showed divergent banding patterns. Expected frequencies of isolates with divergent banding patterns were calculated for each subsample. In the Italian subsample, isolates with divergent banding patterns were significantly more frequent than expected. At the same time, isolates from Italy had significantly fewer virulence factors than those from N.W. Europe, indicating weaker selection by host resistance genes. It is suggested that isozyme uniformity in the homogeneous north‐western European barley powdery mildew population has arisen from strong selection pressures for specific virulence genes. The direction of this selection, acting upon a mainly asexually reproducing population, has changed over space and time due to the introduction of new resistance genes, forcing local populations through bottlenecks. This may have led to random loss of genetic variation (genetic drift) in the barley powdery mildew gene pool.
Characterization of Deoxyribonucleic Acid of Virulent Bacteriophage and its Infectivity to Host Bacteria, Pseudomonas solanacearum
Authors: Toyoda H. , Kakutani K. , Ikeda S. , Goto S. , Tanaka H. , Ouchi S. 
Published: May 2008

AbstractVirulent bacteriophage PK‐101 was isolated from soil infested with strain K‐101 of Pseudomonas solanacearum and nucleic acid was prepared from the phages. Some chemical properties of phage nucleic acid and its infectivities to various strains of P. solanacearum were examined in the present study. By digestion with restriction endonucleases, phage nucleic acid was shown to be linear duplex DNA approximately 35 kb long. Restriction fragment length polymorphism was observed when electrophoresis patterns of enzyme‐digested PK‐101 DNA were compared with those of DNA prepared from different phage isolates. Transfection of host strains by PK‐101 DNA was carried out, and it was infectious not only to host strain K‐101, but also to other strains which were resistant to phage particles. Transfection efficiency was considerably enhanced by directly introducing phage DNA into bacterial cells by means of an electroporation. The electroporation technique was also effective to transform P. solanacearum with large‐size plasmid DNA.
Differentiation of the Soft‐Rotting Erwinias (the Carotovora Group) by Fatty Acid Composition
Authors: Wells J. M. , Moline H. E. 
Published: May 2008

AbstractAbout 90 % of total cellular fatty acids in E. carotovora, grown on KB medium for 1 day at 28°C, were the saturated, even‐carbon straight chains 12 : 0 (5.9%), 14 : 0 (1.7%) and 16 : 0 (30.1 %), and the unsaturated 16 : 1 (36.6%) and 18 : 1 (15.0%) fatty acids. Other components were the hydroxy‐substituted 3‐OH 14 : 0 (5.3%) and 21 minor fatty acids each occurring less than 0.1 % of the total — 14 of them reported herein for the first time in Erwinia. The ratio of 16 : 1/18 : 1 in KB‐grown cells was as useful in differentiating subspecies of E. carotovora as previously reported by other workers for TSA‐grown cells. A comparison of fatty acid profiles of E. carotovora on 4 different media, KB, TSA, NA and PDA, indicated that on KB there was the greatest proportion of Class A and C fatty acids, and the highest number of detectable components. Significant differences were noted in the 5 major fatty acids and in cyclic fatty acids among the 4 species of the carotovora group –E. carotovora, E. chrysanthemi, E. rhapontici and E. cypripedii. These differences could be expressed as algorithms that, when used in sequential dichotomous steps, could differentiate the 4 species.
Effects of Infection Density on the Size of Barley and Wheat Leaf Rust Colonies before and on the Size of Uredia after the Start of Sporulation
Authors: Baart P. G. J. , Parlevliet J. E. , Limburg H. 
Published: May 2008

AbstractThree barley genotypes were exposed to four different inoculum densities of barley leaf rust, Puccinia hordei. Colony area well before first sporulation and uredia size well after the start of sporulation were measured. In a second series two barley and two wheat cultivars were exposed to four different inoculum densities of barley and wheat leaf rust (P. recondita f. sp. tritici), respectively.Before the sporulation is initiated the colony size was independent of the uredia density. This was valid for densities ranging from approximately 7 to over 200 uredia per cm2 leaf area. After the sporulation had started the uredia size was strongly dependent on the uredia density. The size of the uredia was approximately halved when the uredia density increased from about 10 to about 150 per cm2. The urediospore production per uredium decreased much stronger with increased uredia density.
Amylase Activity May Play a Role in the ‘Pathosmosis’ Thought to Develop in the Areas of Virus Localization in Plants
Authors: Wagih E. E. 
Published: May 2008

AbstractTobacco necrosis virus causes both qualitative and quantitative differences in the total soluble protein fraction and amylase isozymes of cucumber (Cucumis sativus L. cv. Beit Alpha MR) cotyledons. A constitutive amylase isozyme with an Rf value of 1.0 on 10 % polyacrylamide gel is detected in both healthy and TNV‐infected tissue. In addition, a major (Rf 0.70) band of amylase activity was located in virus‐infected but not in healthy, abraded tissue. It is proposed that the previously observed osmotic stress conditions prevailing in areas of virus localization (Pathosmosis) is likely to be due to the induced amylase activity with subsequent local accumulation of free sugars. The results presented in this paper may elucidate the biological function of the major component of the γ fraction, a stress‐related protein known to be induced in cucumber cotyledonary leaves following exposure to biotic or abiotic agents.Zusammenfassung Amylaseaktivität könnte eine Rolle bei der “Pathosmosis” spielen, von der man glaubt, sich in Bereichen der Viruslokalisierung in Pflanzen zu entwickeln Tobacco necrosis vims (TNV) verursacht sowohl qualitative wie auch quantitative Unterschiede in der gesamt löslichen Proteinfraktion und Amylase‐Isoenzymen von Gurke (Cucumis sativus L., Sorte Beit Alpha MR)‐Kotyledonen. Ein konstitutives Amylase‐Isoenzym, mit einem Rf‐Wert von 1,0 bei 10%igem Polyacrykmidgel, wurde bei gesunden und TNV‐infiziertem Gewebe beobachtet. Außerdem wurde eine Hauptzone von Amylaseaktivität (Rf 0,70) bei infiziertem, aber nicht bei gesundem, abgeriebenem Gewebe ermittelt. Es wird behauptet, daß die durch osmotischen Streß verursachten Bedingungen im Berdch der Viruslokalisierung (Pathosmosis) wahrscheiniich durch die induzieite Amylaseaktivität, die wiederum zu einer lokalen Ansammlung von freien Zuckem führt, verursacht werden. Die in dieser Arbeit dargesteliten Ergebnisse könnten die biologische Funktion der Hauptkomponente der γ‐Fraktion, ein streßgebundenes Protein, erklären, welches bekannt ist, daß es in Gurkenkotyledonen nach einer Aussetzung zu biotischen oder abiotischen Agenzien induziert wird.
Pectolytic Enzymes from Interactions between Pseudomonas syringae pv. Phaseolicoia and French Bean (Phaseolus vulgaris)
Authors: Longland Annette C. , Slusarenko A. J. , Friend J. 
Published: May 2008

AbstractPectolytic enzymes were extracted from both compatible and incompatible interactions between Pseudomonas syringae pv. phaseolicola and French bean. Much lower levels of activity were obtained from control, buffer‐inoculated leaves.Temperature and pH optima were similar for enzyme extracted from both inoculated and control leaves. Temperature and pH profiles were similar for enzymes from compatible and incompatible interactions, but different from those of the controls.Enzyme activity in inoculated leaves did not increase until 20 h after inoculation, but then increased rapidly over the succeeding 2–3 days. Activity from control leaves had increased marginally by 48 h after inoculation, but then decreased to about 50 % of the original level.Enzymes from incompatible and compatible interactions both had pi values of 7.7. Substrate degradation studies and analysis of reaction products indicated that the enzymes were endopolygalacturonases. HPLC indicated that the enzyme from the compatible interaction had a relative molecular mass of approximately 44,000. When injected into leaves the partially purified enzyme was a potent elicitor of phytoalexin accumulation.Zusammenfassung Pektolytische Enzyme aus der Wechselwirkung zwischen Pseudomonas syringae pv. phaseolicola und der Gartenbohne (Phaseolus vulgaris) Pektolytische Enzyme wurden sowohl aus verträglichen als auch aus nicht verträglichen Wechselwirkungen zwischen Pseudomonas syringae pv. phaseolicola und der Gartenbohne extrahiert. Viel niedrigere Aktivitatsgrade wurdcn aus den mit Puffern inokulierten Kontrollblättem ermittelt.Temperatur‐ und pH‐Optima waren für die Enzyme aus inokuUerten bzw. nicht inokulierten Blänem ähnlich. Temperatur‐ und pH‐Profile der Enzyme aus verträglichen und nicht verträglichen Wechselwirkungen waren ähnlich, aber unterschieden sich von denen der KontroUe.Die Enzymaktivität in inokulierten Blättem stieg erst 20 h nach der Inokulation an, eine weitere, schneile Steigerung folgte jedoch über die nächsten 2–3 Tage. Bei der KontroUe konnte eine minimale Steigerung 48 h nach der Pufferinokulation ermittek werden, fiel dann aber zuriick auf ca. 50 % des Ausgangswertes.Die Enzyme aus verträglichen und nicht verträglichen Wechselwirkungen hatten pl‐Werte von 7,7. Substratabbaustudien sowie eine Analyse der Reaktionsprodukte zeigten, daß es sich um EndoPolygalacturonase‐Enzyme handelt. HPLC‐Untersuchungen zeigten, daß das aus den verträglichen Wechselwirkungen stammende Enzym eine relative Molekularmasse von ca. 44 000 besaß. Nach einer Spritzung in Blättern fungierte das zum Teil aufgereinigte Enzym als ein starker Elicitor der Phytoalexinakkumulation.
Bioassay of Toxins as a Diagnostic Method for Pseudomonas syringae Pathovars
Authors: Wei Y. D. , Mortensen C. N. 
Published: May 2008

AbstractSix pathovars of Pseudomonas syringae were tested for bioassay of toxins. P. syringae pv. syringae and pv. maculicola showed an inhibitory effect on the growth of Escherichia coli in mineral medium. The inhibition for P. syringae pv. syringae was reversed by L‐arginine, not by L‐glutamine and L‐citrulline. It appears that the biochemical target of the toxin(s) from P. syringae pv. syringae is involved in the metabolism of citrulline to arginine in the urea cycle. Under the experimental conditions, the toxin activity was not detected with the isolate of P. syringae pv. phaseolicola in vitro, but the isolate retained it's pathogenicity in a susceptible variety of bean.Zusammenfassung Bioassay von Toxinen als Methode zur Diagnostizierung von Pseudomonas syrrngae‐Pathovaren Die Toxinaktivität von sechs Pathovaren von Pseudomonas syringae wurde in einem Biotest geprüft. P. syringae pv. syringae und pv. maculicola zeigten eine hemmende Wirkung auf das Wachstum von Escherichia coli in Mineralmedium. Die Hemmung von P. syringae pv. syringae wurde durch L‐Arginin aufgehoben, jedoch nicht durch L‐Glutamin und L‐Citrullin. Es scheint, daß die biochemische Erkennungsstelle (Target) des Toxins von P. syringae pv. syringae in Verbindung steht mit dem Metabolismus von Citrullin zu Arginin im Harnstoffzyklus. Unter den Versuchsbedingungen konnte in vitro keine Toxizität bei P. syringae pv. phaseolicola gefunden werden, jedoch behielt das Isolat seine Pathogenität gegenüber einer empfindlichen Bohnenart.
Artenspektrum der Aphidenvektoren des clover yellow vein potyvirus (Kleegelbadrigkeits‐Virus)
Authors: Karl E. , Schmidt H. E. , Giersemehl I. 
Published: May 2008

Abstract Range of aphid vector species of the clover yellow vein potyvirus A Central European isolate of the clover yellow vein potyvirus (CYVV) from Trifolium repens L. was tested for its transmissibility by 20 aphid species using Vicia faba L. as virus source and test plant species. All tested aphid species were able to transmit this isolate. Depending on the aphid species, the proportion of infected test plants ranged between 35 and 82.5 per cent. As new vectors of CYVV 17 aphid species were ascertained. The following species could be of special epidemiological importance for the spread of CYVV: Acyrthosiphon pisum (Harr.), Aphis fabae Scop., Aphis nasturtii Kalt., Brevicoryne brassicae (L.), Macrosiphum euphorbiae (Thom.), Metopolophium dirhodum (Walk.), Myzus persicae (Sulz.), and Rhopalosiphum padi (L.).ZusammenfassungEin mitteleuropäisches Isolat des Kleegelbadrigkeits‐Virus (clover yellow vein potyvirus, CYVV) von Trifolium repens L. wurde auf seine Übertragbarkeit durch 20 Aphidenarten untersucht. Als Virusquelle und Testpflanze diente Vicia faba L. Alle geprüften Aphidenarten waren zur Übertragung dieses Isolates befähigt. Der Anteil infizierter Testpflanzen lag je nach Blattlausart zwischen 35 und 82,5 %. Als neue Vektoren für das CYVV konnten 17 Aphidenarten ermittelt werden. Es wird eingeschätzt, daß insbesondere die folgenden Arten für die Ausbreitung des CYVV epidemiologische Bedeutung haben können: Acyrthosiphon pisum (Harr.), Aphis fabae Scop., Aphis nasturtii Kalt., Brevicoryne brassicae (L.), Macrosiphum euphorbiae (Thom.), Metopolophium dirhodum (Walk.), Myzus persicae (Sulz.) und Rhopalosiphum padi (L.).
Wirkung der pflanzengesundheitsfördernden Rhizobakterien Agrobacterium radiobacter und Bacillus sphaerkus auf den Globodera pallida‐Befall der Kartoffel und das Pflanzenwachstum
Authors: Racke J. , Sikora R. A. 
Published: May 2008

Abstract Influence of the plant health‐promoting rhizobacteria Agrobacterium radiobacter and Bacillus sphaericus on Globodera pallida root infection of potato and subsequent plant growth The plant health‐promoting rhizobacteria (PHPR) Agrobacterium radiobacter and Bacillus sphaericus as well as a blend of both bacteria were tested under greenhouse and field conditions for their ability to reduce Globodera pallida root infection on the potato cultivar ‘Hansa’. In greenhouse tests the PHPR, sprayed individually, caused a significant reduction (p = 1 %) of approximately 41 % in nematode penetration whereas the blend had no effect on the infection process. Under field conditions the blend caused a significant (p = 1 %) 31 % and the treatment with B. sphaericus alone a significant (p = 1 %) 29 % reduction in penetration. Nematode reproduction was reduced significant by (p = 1 %) 51 % following application of B. sphaericus. The reduction in final cyst number detected in the field trials in the PHPR treatments was not statistically significant. Increased root growth was not observed in either the greenhouse or the field trials. However, tuber yield increased by 18 % and 22 % in the field trials when the tubers were treated with A. radiobacter or the blend, respectively. There was a significant increase (p = 5 %) of 38 % in the number of tubers per plant in the treatment with the blend.ZusammenfassungDie pflanzengesundheitsfördernden Rhizobakterien (PGFR) Agrobacterium radiobacter und Bacillus sphaericus sowie deren Mischungen wurden unter Gewächshaus‐ und Feldbedingungen in ihrer Wirkung auf den Globodera pallida‐Befall der Kartoffelsorte Hansa untersucht. Die Einzelbehandlungen der PGFR bewirkten im Gewächshaus eine signifikante (p = 1%) ca. 41%ige Reduktion der Nematodeneindringung, während die Mischung beider Stämme keinen Einfluß zeigte. Im Freiland hemmte dagegen die Mischungsvariante den Befall signifikant (p = 1 %) um 31% und B. sphaericus signifikant (p = 1 %) um 29%. Die Nematodenvermehrung wurde im Gewächshaus durch B. sphaericus signifikant (p = 1 %) um ca. 51 % gemindert. Im Feld ermittelte Reduktionen der Zystenvermehrung nach Behandlung mit PGFR waren statistisch nicht abzusichern. Einflüsse der Bakterien auf das Wurzelwachstum konnten weder im Gewächshaus noch im Freiland festgestellt werden. Der im Freiland ermittelte Knollenertrag war durch A. radiobacter um ca. 18 % und durch die Mischung der Stämme um ca. 22 % erhöht. Die Anzahl der gebildeten Knollen pro Staude war an den mit beiden Bakterien inokulierten Pflanzen signifikant (p = 5 %) um 38 % höher.