bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction between the Ectomycorrhizal Fungus Paxillus involutus, Damping‐off Fungi and Pinus resinosa Seedlings
Authors: Chakravarty C. , Peterson R. L. , Ellis B. E. 
Published: May 2008

Abstract Paxillus involutus, an ectomycorrhizal fungus, had an inhibitory effect on the root pathogenic fungus Fusarium moniliforme and two isolates of F. oxysporum when grown in paired cultures on modified Melin Norkrans’ medium. In contrast, one isolate of F. oxysporum was not inhibited and another damping‐off fungus, Cylindrocarpon destructans inhibited growth of Pax. involutus in similar paried cultures. Survival of Pinus resinosa (red pine) seedlings was increased significantly when they were grown in vitro concomitantly with either Pax. involutus and F. moniliforme or Pax. involutus and the three isolates of F. oxysporum, compared with seedlings inoculated with either F. moniliforme or F. oxysporum isolates alone. pax. involutus showed no protective effect against C. destructans. The number of colony forming units of Fusarium spp. was reduced significantly in the root extract and rhizosphere substrate of P. resinosa seedlings inoculated with Pax. involutus. Spore germination of Fusarium spp. was reduced significantly when treated with culture filtrate of Pax. involutus and root extract of P. resinosa seedlings inoculated with Pax. involutus. Neither colony forming units nor spore germination of C. destructans was affected either by culture filtrate of Pax. involutus or root extract of P. resinosa seedlings inoculated with Pax. involutus.
Teliospore Germination of Soybean Rust Fungus (Phakopsora pachyrhizi Syd.)
Authors: Saksirirat W. , Hoppe H.‐H. 
Published: May 2008

AbstractTeliospores of the soybean rust fungus (Phakopsora pachyrhizi Syd.) germinated after treatment with 10—12 wetting and drying cycles at room temperature. Spores swelled, vacuolated and germinated with a slightly curved basidium bearing 1—4 sterigmata with basidiospores. High germination rates were observed when telia were stored at 5 °C for 5—6 months before breaking dormancy.
Early Changes in the Nucleotide Pools of Germinating Rust Uredospores
Authors: Grabo P. , Wagner K. G. 
Published: May 2008

Abstract Puccinia graminis uredospores were induced to germinate on a water surface and the nucleotide/nucleoside pools were determined by high performance liquid chromatography. Distinct phases of germination could be discriminated by correlating the changes of individual nucleotide pools with characteristic morphological changes. During the first 15 min no visible changes of the cell wall were observed whereas the adenine nucleotide pools increased strongly indicating an activation of the energy metabolism. The stage preceding hyphal growth revealed large increases in the precursor pool for cell wall synthesis (UDP‐N‐acetylglucosamine). The early phases of germination are obviously controlled by distinct metabolic transitions. Furthermore, correlations of pool contents and changes during germination with the germination efficiency of the three uredospore batches investigated are discussed.
Relationship between Phytotoxicity of Metabolites Produced in vitro by Strains of Phoma tracheiphila (Petri) Kanc. et Ghik. and Their Virulence
Authors: Rosciglione B. , Burgio A. , Bottalico A. , Laviola C. 
Published: May 2008

AbstractThree wild isolates and three mutants of Phoma tracheiphila (Petri) Kanc. et Ghilk. were tested for virulence on young Lemon trees. Their respective culture filtrates were tested for toxicity to Tomato cuttings and Sour orange and Lemon leaves. No relationship between phytotoxicity of metabolites produced in vitro and virulence resulted.
Bacterial Streak Disease of Maize (Zea mays L.) in South Africa
Authors: Coutingo T. A. , Wallis F. M. 
Published: May 2008

AbstractBacterial streak disease of maize is currently causing some concern among breeders in South Africa. The causal organism of this previously undescribed disease was successfully isolated and its pathogenicity established using KoCH's postulates. Standard physiological and biochemical tests used to identify phytopathogenic bacteria indicated that the bacterium is a Xanthomonas campestris pathovar. Comparisons between this organism and other recognized X. campestris pathovars of the Poaceae indicated that apart from some minor differences the maize streak pathogen is physiologically similar to X. campestris pv. holcicola. However, in repeated reciprocal inoculation experiments all attempts to induce disease symptoms in sorghum with the maize streak pathogen were unsuccessful. Conversely, X. campestris pv. holcicola did produce symptoms in maize leaves. In all the maize cultivars tested the symptoms produced by the maize streak pathogen were, however, always considerably more severe than those caused by X. campestris pv. holcicola. Notwithstanding its physiological similarity to X. campestris pv. holicola it would appear that on the grounds of host specificity the maize streak pathogen warrants new pathovar status. The name X. campestris pv. zeae is proposed.
Comparison of Different Inoculation Techniques to Screen Resistance of Pea Lines to Downy Mildew
Authors: Stegmark R. 
Published: May 2008

AbstractPea lines with partial resistance to downy mildew were tested with different inoculation techniques. Lines with superior resistance to leaf and pod infection in the field also show superior resistance to artificial inoculation of germinating seeds or seedlings at different ages in greenhouse experiments. Increased resistance of older seedlings was found for all genotypes including the susceptible control. Juvenile leaves at the top of the seedlings plants at time of inoculation, developed the strongest symptoms. Selection for partial resistance can probably be carried out in the greenhouse to improve resistance of adult plants in field.
Mitigation of Tomato Spotted Wilt Virus Infection and Symptom Expression by Water Stress
Authors: Córdoba A. R. , Taleisnik E. , Brunotto M. , Racca R. 
Published: May 2008

AbstractThe effects of water stress on the infection and systemic movement of tomato spotted wilt virus (TSWV) in vegetative tomato plants are examined. Two groups of plants: water stressed (water potential −1.31 MPa) and well‐watered ones (water potential −0.65 MPa), were mechanically inoculated on the third expanded leaf from the top. Each group was then divided into a well‐watered and a water stressed one.TSWV inoculation was effective both on water‐stressed and well‐watered plants. In all groups, infection was first detected in roots, then in shoot apices and subsequently in the rest of the leaves. Systemic virus infection was somewhat slower in the water stressed plants. Post inoculation stress treatments had a significant effect in reducing infection as well as in attenuating TSWV symptoms.Results from the present work suggest that water stress may be effective in controlling virus concentration and systemic infection symptoms in tomato plants and could thus be used as a tool to study the regulation of development of TSWV infection in this system.
Structure of Syncytia Induced by Heterodera avenae Woll. in Roots of Susceptible and Resistant Wheat (Triticum aestivum L.)
Authors: Grymaszewska Grazyna , Golinowski Wladyslaw 
Published: May 2008

AbstractThe structure of syncytia induced by Heterodera avenae in roots of susceptible Triticum aestivum cv. ‘Capa’ and resistant wheat AUS 10894 was investigated. In susceptible plants the first syncytia were observed 4 days after placing the seedlings into a substrate containing nematode cysts. They were located on different root levels. In resistant plants syncytia were first found after 14 days, exclusively in the root maturity zone. In both wheats syncytia consisted mostly of stelar parenchymatic cells. The syncytia induced in roots of Triticum aestivum AUS 10894 were characterized by less immediate contact with the host tracheary elements than the syncytia induced in roots of susceptible Triticum aestivum cv. ‘Capa’. In both wheats a stimulation of pericycle cell divisions, giving rise to lateral roots, was found in parts where the syncytia developed.
Incidence of Stenocarpella and Fusarium Cob Rots in Monoculture Maize under Different Tillage Systems
Authors: Flett B. C. , Wehner F. C. 
Published: May 2008

AbstractThe incidence of maize cob rot caused by Stenocarpella maydis, S. macrospora, Fusarium moniliforme, F. subglutinans and F. graminearum was determined over two seasons under different tillage systems at various localities. Tillage had no effect on Fusarium spp. cob rots. S. macrospora occurred only at one locality, viz. Cedara, and no tillage effect was observed. Ploughing reduced the incidence of S. maydis cob rot at localities which had high incidences of disease. The relationship between severity of S. maydis cob rot and surface stubble mass was linear.
Intra‐ and Interspecific Variation in Plant Response to Inoculation with Deleterious Rhizosphere Pseudomonads
Authors: ÅStröm Boel 
Published: May 2008

AbstractAccessions of wheat, spinach, lettuce and differentBrassicaspecies were tested in greenhouse experiments for reaction to inoculation with two isolates of growth‐inhibitory rhizosphere bacteria. Seedlings grown in non‐sterile soil were inoculated with bacterial suspension and shoot dry weight was measured after five weeks. Large differences were found between the plant species tested in their average sensitivity to each bacterial isolate, and in the majority of plant species, significant differences were also found between accessions in the response to one or both isolates. These findings suggest that, in addition to the variation between plant species, intraspecific variation in the reaction to deleterious bacteria is a common feature in plants. This supports the hypothesis that plant reaction to rhizosphere bacteria is under genetic control. The results further indicate specificity in the interactions between plants and bacterial isolates, both at the plant species level and at the accession level.
Strains of Colletotrichum coffeanum Noack Causing Coffee Berry Disease in Angola and Malawi with Characteristics Different to the Kenya Strain
Authors: Rodrigues C. J. , Varzea V. M. P. , Hindorf H. , Medeiros Emilia F. 
Published: May 2008

AbstractStrains of Colletotrichum isolated from berries of Coffea arabica from Angola and Malawi were identified as C. coffeanum causing coffee berry disease (CBD). The isolates were highly aggressive to berries of the cultivar ‘Catimor’ and produced high numbers of acervuli and extremely large masses of pink conidia when cultivated in the dark. These strains are apparently different in aggressiveness and morphology to those described in the past from Kenya.
Population Tendencies of Pseudomonas cichorii and P. syringae pv. garcae in Young and Mature Coffee Leaves
Authors: Oliveira J.R. , Romeiro R.S. , Muchovej J.J. 
Published: May 2008

AbstractThe population tendencies of Pseudomonas cichorii and P. syringae pv. garcae in young and mature coffee leaves were determined by inoculating streptomycin resistant bacterial cells from 24 h cultures into young and mature coffee leaves. The leaves were then sampled daily for 5 days and the number of bacterial cells per g of leaf tissue was determined. Pseudomonas cichorii increased in mature leaves only while P. syringae pv. garcae increased in young leaves. Symptom development was dependent on the presence of a large number of bacterial cells in the host tissue and coincided with the maximum content of bacterial cells in the leaf.
Comparative Ultrastructural Observations of Plasmalemmasomes in PSTVd‐Infected Healthy and Artificially Stunted Tomato Leaves
Authors: Gruner R. , Santore U. J. 
Published: May 2008

AbstractPlasmalemmasomes were observed in leaves of healthy, PSTVd (potato spindle tuber vroid) infected and artifically stunted tomato plants. Their shape and distribution could not be clearly related to infection with PSTVd as previously suggested. These membranous proliferations were suggested to represent one of the normal physiological responses of the plants to a multitude of possible exogenous influences.
A Comparative Study of the Effects of Five Chemicals on the Survival of Chlamydospores of Fusarium oxysporum f. sp. narcissi
Authors: Linfield Christine A. 
Published: May 2008

AbstractFormaldehyde is routinely used in hot water treatment for the control of narcissus basal rot (caused by Fusarium oxysporum f. sp. narcissi) and stem and bulb eelworm (Ditylenchus dipsaci). It does not kill all the thick walled chlamydospores of F. oxysporum. Four chemicals were evaluated for their efficacy against F. oxysporum by comparing them with the standard formaldehyde rate. At rates of 0.25% a.i. or more, a glutaraldehyde formulation (Cidex) killed 100% of spores within 160 min. Peratol, a hydrogen peroxide and peracetic acid containing formulation, gave 100% kill after 80 min at a concentration of 0.5%. A thiabendazole formulation (Storite Clear Liquid) killed all the chlamydospores. Decon 90 failed to control the fungus adequately.Formaldehyde (as 0.5% commercial formalin) gave good, but not total, control of the fungus but, at higher rates (2.5%), caused flower malformation and corkiness of bulb base plates.The results suggest that Cidex and Peratol, as they are more effective than formaldehyde in controlling the fungus and less unpleasant to use, may be suitable replacements.
A Pathotype Classification for Mycosphaerella pinodes
Authors: Clulow S. A. , Lewis B. G. , Matthews P. 
Published: May 2008

AbstractGenetic variation of Mycosphaerella pinodes in the pathogenesis of Pisum sativum is described for the first time. On a particular host line, isolates varied from those producing a few necrotic flecks to those causing large lesions on stems or leaves. Based on reactions of nine differential host lines, 45 isolates from a wide range of geographical locations could be classed, by stem symptoms, into 9 groups or, by leaf symptoms, into 16 groups.
Cellulolytic Actitivity of Penicillium digitatum and P. italicum Related to Fungal Growth and to Pathogenesis in Citrus Fruits
Authors: Barkai‐Golan Rivka , Karadavid Rachel 
Published: May 2008

AbstractCultural conditions under which Penicillium digitatum and P. italicum develop were an important factor in determining the extent of their cellulolytic activity. At pH 5.5–7.5 of the culture medium, Cx‐cellulase activity was correlated with mycelial dry weight. However, at pH 4.5 and more so at pH 3.5, activity was markedly reduced while fungal growth was not affected. Cx‐cellulases of both species were not induced by the presence of carboxymethyl cellulose as a carbon source and were defined as constituent enzymes. Cellulase activity of the two Penicillia on different carbon sources was detected prior to the initiation of sporulation. A sporeless mutant of P. digitatum exhibited cellulolytic activity similar to that of the normal strain, suggesting no role for sporulation in the Cx‐cellulase synthesis.Cx‐cellulase activity in Valencia oranges started during the early stages of pathogenesis, before the appearance of disease symptoms. Correlation between the cellulase activity and the severity of the disease symptoms was apparent during the first three days after inoculation. At the end of the incubation period both fungi almost reached their maximum enzymatic activity, whereas the disease index continued to rise gradually until total fruit rot was achieved. A possible role of Cx‐cellulases of the two Penicillia in the early stages of pathogenesis was suggested.
Flavescence dorée de la Vigne. Présence de MLO et Effets Cytopathogènes Associés, dans le Liber de la Vigne
Authors: Meignoz R. , Boudon‐Padieu E. , Larrue J. , Caudwell A. 
Published: May 2008

RésuméL'agent pathogène de la Flavescence dorée (FD), difficilement decelable dans les vignes malades prelevees au champ a pu être visualise dans le liber de l'hybride LN33 infecté artificiellement en serre, au stade de jeunes boutures, par la cicadelle vectrice Scaphoideus titanus. Le MLO (mycoplasmalike organism) de la FD induit des effets cytopathologiques importants qui précèdent la mort de nombreuses cellules dans les assises libériennes infectées. La necrose des cellules n'est pas toujours associée a la présence de MLO au moment de l'observation.Abstract Grapevine Flavescence dorée. Presence of MLO and associated cytopathoiogical effects in grapevines Grapevine Flavescence dorée MLO is difficultly found in tissues of infected grapevines from the field. Numerous MLO cells were found in sieve tubes of grapevine cuttings cv. LN33 which were infected with Scaphoideus titanus from a contamined vineyard, and grown in a greenhouse. Important cytopathoiogical disorders of MLO invaded tissues occurred before the death of numerous phloem cells. Cell necrosis was not always related to presence of MLOs at die moment of observation.Zusammenfassung Flavescence dorée der Rebe. Das Vorhandensein von MLO und die assoziierten cytopathologischen Effekte im Rebenbast Flavescence dorée MLO der Rebe kann nur mit Schwierigkeiten im Gewebe von infizierten Pflanzen im Feld ermittelt werden. Zahlreiche MLO‐Zellen wurden in Siebelementen von Rebpflan‐zenstecklingen cv. LN33 gefunden, die mit Scaphoideus titanus künstlich im Gewächshaus infiziert wurden. Wichtige cytopathologische Veränderungen des MLO‐infizierten Gewebes wurden vor dem Absterben zahlreicher Phloemzellen beobachtet. Zellnekrosis konnte nicht immer mit dem Vorhan‐densein von MLOs zum Zeitpunkt der Beobachtung verbunden werden.
Demonstration of Mycoplasmas in Prunus Species in Germany
Authors: Lederer W. , Seemüller E. 
Published: May 2008

AbstractIn southwestern Germany, mycoplasmas were detected in peach (Prunus persica), apricot (P. armeniaca), almond (P. amygdalus), Japanese plum (P. salicina) and flowering cherry (P. serrulata). The infected trees showed yellowing and leaf roll symptoms as well as reduced terminal growth, die‐back, and decline. This is the first report on the detection of mycoplasmas in Prunus spp. In Germany.Zusammenfassung Nachweis von Mycoplasmen in Prunus‐Arten in Deutschiand In Südwestdeutschland wurden Mycoplasmen in Pfirsich (Prunus persica), Aprikose (P. armeniaca), Mandel (P. amygdalus), japanischer Pflaume (P. salicina) sowie in der Zierkirsche P. serrulata nachgewiesen. Die befallenen Bäume wiesen als wichtigste Symptome Blattvergilbung, Blattrollen, Kümmerwuchs und Absterbeerscheinungen auf. Dies ist der erste gesicherte Nachweis von Mycoplasmen in Prunus‐Arten in Deutschland.
Comparison of Thermal and Chemical Treatment of Cotton Seed to Control Bacterial Blight (Xanthomonas campestris pv. malvacearum)
Authors: Honervogt B. , Lehmann‐Danzinger H. 
Published: May 2008

Abstract Xanthomonas campestris pv. malvacearum (X. c. malvacearum) was isolated from cotton seeds from Nicaragua. Thermal treatment with hot water—ranging from 55 °C to 71 °C—for 20 min, was tested on naturally and artificially infected undelinted cotton seed. Germination was reduced only above 67 °C (17 % at 71 °C), but the degree of infection was severely reduced above 55 °C reaching 0 % at 65 °C. Bronopol treatment reduced the amount of infected linted seed from 91 % to 39 % and acid delinting from 17 % to 0.5 %. In contrast to the thermal treatments the chemical treatments eliminated X. c. malvacearum only from the seed surface and not from inside. Chemical treatment may be sufficient for externally infected cotton seed with low infection rate but not under conditions with high infection rates, where seed is also infected internally. Acid delinting could reduce the infection effectively, but not completely. The only possible way to avoid introduction of X. c. malvacearum or new races in already infested areas is thermal treatment of seed and should always be applied for quarantine.Zusammenfassung Vergleich von Wärme‐ und chemischen Behandlungen zur Bekämpfung der Eckigen Blattfleckenkrankheit (Xanthomonas campestris pv. malvacearum) an Baumwollsaatgut Xanthomonas campestris pv. malvacearum (X. c. malvacearum) wurde von Saatgut aus Nicaragua isoliert. Warmwasserbehandlungen zwischen 55 °C und 71 °C für 20 min wurden an natürlich und künstlich infiziertem Saatgut mit Filz (linters) getestet. Die Keimfähigkeit wurde nur bei Temperaturen über 67 °C reduziert (17% bei 71 °C), dagegen verringerte sich der Infektionsgrad erheblich bei Temperaturen von über 55 °C und erreichte 0 % bei 65 °C. Eine Behandlung mit Bronopol verringerte den Befall von 91 % auf 39 %, und eine Schwefelsäurebehandlung von 17 % auf 0.5 %. Im Gegensatz zur Warmwasserbehandlung wurde durch eine chemische Behandlung X. c. malvacearum nur an der Oberfläche, nicht aber im Inneren des Saatgutes abgetötet. Eine chemische Behandlung sollte bei äußerlich infiziertem Saatgut bei geringen Infektionsraten ausreichen, nicht aber bei hohen Raten und intern infiziertem Saatgut. Eine Schwefelsäurebehandlung konnte die Infektion stark reduzieren. Um die Einschleppung von X. c. malvacearum oder neuer Rassen des Erregers zu vermeiden, ist eine Warmwasserbehandlung des Saatguts, insbesondere in der Quarantäne, unumgänglich.
A Strain of Cucumber Green Mottle Mosaic Virus (CGMMV) from Bottlegourd in Saudi Arabia
Authors: Al‐Shahwan Ibrahim M. , Abdalla Omer A. 
Published: May 2008

AbstractMosaic symptoms were observed on bottlegourd in the College of Agriculture Research and Experimental Farm at Dirab. The following plant species: Lagenaria siceraria L., Cucumis sativus L., C. melo L., and Citrullus vulgaris L. showed mosaic symptoms when mechanically inoculated with extract from symptomatic bottlegourd. The rest of the inoculated plants did not show any symptoms. Properties of the infective plant extract were as follows: Dilution end point (DEP) was between 10−6–10−7, thermal inactivation point (TIP) was between 90–100 °C, and longevity in vitro was more than 32 days. Electron microscopic examination of negatively stained, partially purified preparations revealed rigid‐rod shaped virus particles measuring 300–325 nm. Positive serological reaction was observed between leaf extract from infected bottlegourd and CGMMV antiserum in immunodiffusion test in agar plates. This report is the first of the presence of CGMMV in this country.Zusammenfassung Ein Isolat des cucumber green mottle mosaic virus (CGMMV) aus dem Flaschenkürbis in Saudi‐Arabien Mosaiksymptome wurden an Flaschenkürbis bei dem College of Agriculture Research and Experimental Farm in Dirab, Saudi‐Arabien, beobachtet. Nach einer mechanischen Inokulation mit dem Extrakt aus befallenen Flaschenkürbispflanzen zeigten die folgenden Pflanzenarten Mosaiksymptome: Lagenaria siceraria L., Cucumis sativus L., C. melo L. und Citrullus vulgaris L. Andere Pflanzenarten, die gleichzeitig inokuliert worden waren, zeigten keine Symptome. Der infektiöse Pflanzenextrakt hatte folgende Eigenschaften: der Verdünnungsendpunkt (DEP) lag zwischen 10−6 und 10−7, der thermale Inaktivierungspunkt lag zwischen 90–100 °C, und die Langlebigkeit in vitro betrug mehr als 32 Tage. Elektronenmikroskopische Untersuchungen von negativ gefärbten, partiell gereinigten Präparaten offenbarten stabile, stabähnliche Viruspartikeln, die eine Größe von 300–325 nm hatten. Immunodiffusionstests in Agarplatten zeigten eine positive serologische Reaktion zwischen dem Blattextrakt von infizierten Flaschenkürbispflanzen und dem CGMMV‐Antiserum. Über das Vorhandensein vom CGMMV in Saudi‐Arabien wird hier zum ersten Mal berichtet.