bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accumulation of phytoalexins and isoflavone glucosides in a resistant and a susceptible cultivar of Cicer arietinum during infection with Ascochyta rabiei
Authors: WEIGAND F. , KÖSTER J. , WELTZIEN H. C. , BARZ W. 
Published: May 2008

AbstractAfter infection with spores of a virulent strain of Ascochyta rabiei the chickpea (Cicer arietinum) cultivars ILC 1929 (susceptible) and ILC 3279 (resistant) were compared with regard to pterocarpan phytoalexin and isoflavone accumulation. Quantitative HPLC analyses of total extracts of aerial parts were used to measure the induced formation of the phytoalexins medicarpin and maackiain and the accumulation of the constitutive isoflavones biochanin A and formononetin together with their, 7‐0‐glucosides and their 7‐0‐glucoside‐6″‐0‐malonates. The two cultivars showed no significant difference in the level of isoflavones and isoflavone conjugates. On the other hand, the resistant cultivar ILC 3279 rapidly accumulated large amounts of both, phytoalexins (20–26 nmole g−1 fr.w.) whereas cultivar ILC 1929 only produced very small amounts (5 nmole g−1 fr.w.) of medicarpin. The data are discussed with regard to isoflavonoid metabolism and the significance of induced and constitutive levels of phytoalexins and isoflavones in resistance of chickpea towards A. rabiei.
Untersuchungen zur Anfälligkeit und Resistenz von Kopfsalat (Lactuca sativa) gegen falschen Mehltau (Bremia lactucae) III. Peroxydase‐, peroxydatische Katalase‐und Polyphenoloxydase‐Aktivitäten
Authors: Zinkernagel V. 
Published: May 2008

Abstract Investigations on the susceptibility of head lettuce (Lactuca sativa) to downy mildew (Bremia lactucae) III. Activities of peroxidase, catalase and polyphenoloxidase Host cell walls in contact with intercellular hyphae of Bremia lactucae stain electron positively in susceptible and incompletely resistant varieties of lettuce after appropriate electron microscopy preparation for peroxidase activity. The outer membranes of the mitochondria of the parasite also stained darkly in susceptible varieties whereas in incompletely resistant plants Bremia innermost mitochondrial membranes and host cell mitochondria were darkly stained. This latter observation suggests increased respiration and could be explained as a resistance reaction. Catalase activity was observed in the microbodies of susceptible, in incompletely resistant and healthy varieties. There were no differences in stain intensity in the three kinds of varieties suggesting that catalase activity is not involved in resistance reactions.Polyphenoloxidase activity was infrequently observed on the host cell wall in susceptible and healthy plants, whereas strong activity in incompletely resistant varieties was observed in vesicles in the haustorial sheath. These vesicles were not surrounded by unit membranes and therefore could not have originated from the unit membranes of the extrahaustorial matrix or from the host plasmalemma. They may have been derived from the host protoplast and involved in inactivation of parasite produced toxins thereby contributing to resistance.
Structure‐Activity Relationships as Inferred from Comparative Phytotoxicity of Stemphyloxins and Betaenones
Authors: Manulis Shulamit , Netzer D. , Barash I. 
Published: May 2008

AbstractStructure‐activity relationships of the phytotoxins stemphyloxin I and II from Stemphylium botryosum f. sp. lycopersici were investigated by quantitative comparison of their biological activity with chemically related phytotoxins from Phoma betae, betaenones A, B and C. Phytotoxicity was estimated by inhibition of incorporation of14C‐leucine into proteins of exponentially growing tomato cells. The values of 50 % inhibition for stemphyloxin I and II and for betaenones A, B and C were 0.075, 16, 55, 350 and 1 μM respectively. The β‐ketoaldehyde moiety appeared to be essential in, conferring biological activity and its toxicity was influenced by its spatial orientation. The presence of an hydroxyl group in stemphyloxin I and II enhanced activity in comparison with the respective compounds betaenones C and A which lack this group.
Biological Control of Fusarium spp. in Cotton, Wheat and Muskmelon by Trichoderma harzianum
Authors: Sivan A. , Chet I. 
Published: May 2008

AbstractA new isolate of Trichoderma harzianum (T‐35) was isolated from the rhizosphere of cotton plants from a field infested with Fusarium. Under glasshouse conditions, the antagonist was applied to soil growing in a bran/peat mixture (1:1, v/v) or as a conidial suspension or used as a seed coating. When T. harzianum was tested against Fusarium oxysporum f. sp. vasinfectum, F. oxysporum f. sp. melonis or F. roseum‘Culmorum”, a significant disease reduction, was obtained in cotton, melon and wheat, respectively. Biological control of Fusarium wilt of cotton was achieved when tested at two inoculum levels of the pathogen (2 × 107 and 2 × 108 microconidia/kg soil), decreasing the Fusarium spp. soil population. The long term effect of T. harzianum on Fusarium wilt of cotton was studied using successive plantings. The antagonist persisted in soil throughout three consecutive plantings, reducing the Fusarium, wilt incidence in each growth cycle. At the first planting the largest amount of preparation was found superior, whereas at the third planting, no significant difference could be observed between the four rates of Trichoderma preparation. T. harzianum (T‐35) controlled Fusarium wilt in cotton and muskmelon when applied in both naturally or artificially infested alluvial vertisol and sandy‐loam soils, respectively.Soil or seed treatments with the antagonist provided a similar disease control of F. roseum‘Culmorum’ and of F. oxysporum f. sp. melonis.
Chemical Control of Basal Stem Rot Disease of Tomato (Lycopersicon esculentum Mill.) in Northern Nigeria
Authors: Wokocha R. C. , Ebenebe A. C. 
Published: May 2008

AbstractSix fungicides (Aatopam‐N, Aldrex T, Calixin M, PCNB, captan and captafol) were evaluated at 200 mg a.i.l−1 for their effectiveness in reducing basal stem rot disease incited by Sclerotium rolfsii on tomato in pre‐ and post‐inoculation soil drenches in the glasshouse. The results showed that only PCNB effectively reduced disease severity when applied to soil 10 days before inoculation. Of the two application methods only pre‐inoculation soil drenching with the fungicides was efficacious in reducing disease severity. In field trials conducted in Samaru with Aldrex T, captan and PCNB, only PCNB was effective in combating the severity of the disease. It reduced the disease by about 88% in one trial.
Impact of Host Resistance on the Variability in Virulence of Xanthomonas campestris pv. oryzae
Authors: Nayak P. 
Published: May 2008

AbstractTwenty isolates of Xanthomonas campestris pv. oryzae (Ishiyama) Dye each from susceptible and resistant rice cultivars, were inoculated on the susceptible genotype IR‐8 and resistant M Sungsong to measure the impact of host selection pressure on virulence change. Isolates virulent on resistant genotype tended to be less adaptive on susceptible cultivars. While isolates from susceptible genotype showed 2.2 times more general virulence (GV) than specific virulence (SV), isolates of resistant host origin had only 1.3 times GV, indicating that the resistant host plant displays considerable increase in virulence. The SV value increased 1.64 times after one cropping with resistants indicated the potential of the pathogen to change to be slow.
Factors Affecting the Parasitic Activity of Gliocladium virens on Sclerotia of Sclerotinia sclerotiorum and a Note on its Host Range
Authors: Phillips A. J. L. 
Published: May 2008

AbstractAspects of the biology of Gliocladium virens and parasitism of sclerotia of Sclerotinia sclerotiorum in soil were studied. G. virens parasitized and decayed sclerotia of S. sclerotiorum, S. minor, Botrytis cinerea, Sclerotium, rolfsii and Macrophomina phaseolina on laboratory media and caused a reduction in survival of sclerotia of S. sclerotiorum in soil. It was active over a broad range of soil moisture levels and over the entire agricultural soil pH range. The main factor limiting its use as a biological control agent was its temperature requirements.
In vitro‐Untersuchungen und mikroskopische Studien zur Entwicklung von Phoma chrysanthemicola Hollos f. sp. chrysanthemicola, dem Erreger einer Wurzel‐ und Stengelgrundfäule der Chrysantheme
Authors: Hauptmann G. , Schickedanz F. 
Published: May 2008

Abstract In vitro investigations and microscopic studies about the development of Phoma chrysanthemicola Hollos f. sp. chrysanthemicola, the causal pathogen of a collar and root rot of chrysanthemumsDifferent media were tested for cultivation of Phoma chrysanthemicola. The pathogen grew best on PDA and carrot‐Agar at a temperature of 25°C. The three strains used showed many variations, concerning the structure and colour of the mycelium. Fructification has been promoted by irradiation (ultra‐violer ray). The morphogenesis, especially the formation of pycnidia, conidia and sclerotial structures has been examined with help of the scanning electrone microscope (SEM), results are presented., So far unknown organs probably belonging to the fungus were observed, their identity is still not clear.
Fungistatic Activity of Saponin A from Styrax officinalis L. on Plant Pathogens
Authors: Zehavi U. , Levy M. , Segal R. 
Published: May 2008

AbstractThe antimycotic activity of saponin A from Styrax and of its debenzoylated derivative, Saponin B, was studied on a number of plant pathogens and on Trichoderma viride. Saponin A demonstrated activity against Trichoderma viride, Fusarium oxysporum, Aspargillus niger and Rhizopus mucco. At the concentration tested, Saponin B had low activity only on Trichoderma viride‐ a result discussed in terms of mechanism of action.
Biotic and Abiotic Induction of a Fungitoxic Compound in Rice Bean (Vigna umbellata [Thunb.] Ohwi and Ohashi)
Authors: Datta D. K. , Mukherjee A. K. , Samaddar K. R. 
Published: May 2008

AbstractYoung leaves of rice bean produced relatively more fungitoxic compound(s) than the older leaves. Epicotyls, roots, mature leaves and pods, but not cotyledon and cotyledonary leaves, synthesized the antifungal compound(s) following inoculation with anon‐pathogen of this plant. Epicotyl segments when chopped or pinpricked produced the phytoalexin. Treatment of epicotyls with a dilute concentration of various chemicals caused induction of the fungitoxic compound(s). Induction by inoculation, injury and chemicals suggest a phytoalexin nature of the compound. Presence of phaseollin in the extracts of inoculated, injured or chemical‐treated epicotyls has been demonstrated.
Guignardia citricarpa a Cause of Black Spot on Mango Foliage in Florida1
Authors: McMillan R. T. 
Published: May 2008

AbstractA strain of Guignardia citricarpa Kiely was isolated from infected mango (Mangifera indica L.) leaves. The morphological and physiological characteristics of perithecia and ascospores were identical with those described for G. citricarpa. Inoculated leaves developed lesions 7 to 10 days after ascospore germination. Young lesions appeared as minute, sunken, blackish depressions on upper and lower leaf surfaces. Mature lesions were roughly circular ranging from 1 to 2 mm in diameter. The fungus was consistently reisolated from the lesions which appeared on the leaves, arising from inoculation. Benomyl at 1.7 g/l provided control of black spot.
Rhizothyrium paraskicum sp. nov. (Coelomycetes), ein Blattparasit auf Araucaria araucana (Mol.) C. Koch*
Authors: Butin H. 
Published: May 2008

Abstract
Rhizothyrium parasiticum sp. nov. (Coelomycetes), a leaf parasite on Araucaria araucana (Mol.) C. Koch An imperfect fungus, which causes leaf spots on Araucaria araucana in Chile is described. The usually fairly small necrosis are soon blocked off by a woundperiderm. The placement of this pathogene in the genus Rhizothyrium Naoumoff is discussed.
Diagnostic Procedure for Detection of Viroids and Viruses with Circular RNAs by “Return”–Gel Electrophoresis
Authors: Schumacher J. , Meyer N. , Riesner D. , Weidemann H. L. 
Published: May 2008

AbstractA gel electrophoretic technique for the rapid and sensitive detection of viroids and virusoids is described. Starting from plant material, a typical analysis requires less than 5 hours. Viroid concentrations as low as 800 pg/g tissue can be detected unambiguously without the use of radioactivity, organic solvents, or highly specialized laboratory equipment. The sensitivity may be further increased by introducing additional purification steps. The technique is an essential improvement of the previously published bidirectional gel electrophoretic analysis (Schumacheret al.1983, Anal. Biochem. 135, 288–295). In the new procedure gel electrophoresis is first carried out under native conditions. Before the viroid (or virusoid) bands will leave the gel, conditions are changed to provide denaturing conditions which are achieved by increasing the temperature and changing the buffer. After changing the polarity of the electric field all nucleic acids in the gel “return” in that they now migrate towards their original starting point. Under the denaturing conditions in the second electrophoresis viroids (or virusoids) unfold into the conformation of a circle without in tramolecular base pairs, which structure is unique among the nucleic acids in the gel. The denatured circular viroids migrate in the gel much slower than all other nucleic acids of comparable molecular weight and, therefore stay well separated behind the edge of the other nucleic acids. Thus, viroids can easily be detected on the stained gel as a discrete band.
Slow Leaf Rusting Resistance in Wheat Cultivars VL 422 and Sonalika
Authors: Sharma D. L. , Gupta A. K. 
Published: May 2008

AbstractWheat cultivars VL 422 and Sonalika were found to be slow rusters against two Indian cultures of Puccinia recondita, IL 005 and IL 007, at the adult plant stage, showing lower average disease score and maximum rust severity compared to cultivar CPAN 1425. This slow rusting could not be detected in seedlings of these cultivars.
Correlation between Light and Electron Microscopic Observations and Identification of Mycoplasmalike Organisms using Consecutive 350 nm Thick Sections
Authors: Cousin M. T. , Sharma A. K. , Misra S. 
Published: May 2008

AbstractSerial sections of 350 nm thickness were used to make a correlation between electron and light microscopic observations. While thionin‐acridine orange staining gave a positive result to detect abnormal sieve tubes of phyllody affected Phlox drummondii Hook, when observed under light microscope, the same cells revealed the presence of typical mycoplasmalike organisms (MLOs) in electron microscopic examination. Advantage of 350 nm thick sections in electron microscopy, and the utility of the technique in MLO detection have been discussed.
Specificity of Interactions Between Wild Lactuca spp. and Bremia lactucae Isolates from Lactuca serriola
Authors: Lebeda A. 
Published: May 2008

AbstractSpecificity of interactions between eight Lactuca species and 8 Bremia lactucae isolates was studied in seedlings and adult plants of 36 Lactuca accessions plus one L. serriola × L. sativa hybrid. Pathogenicity of the isolates and/or plant susceptibility was expressed by sporulation intensity.A highly compatible relationship was observed in all of L. serriola accession/isolate interactions tested. A differential reaction was found in numerous cases testifying to physiological specialization of the pathogen in a wild pathosystem. Nonspecific nondifferential compatibility (quantitative resistance) can be expected in L. serriola PI 281876. Age dependent resistance (seedlings versus adult plants, and vice versa) and heterogeneity of reactions were also recorded. The comparisonof B. lactucae isolates from L. sativa and L. serriola has shown a significant shift of pathogenicity in favour of L. serriola accessions. A high level of resistance was found in the L. serriola × L. sativa hybrid.The existence of basic incompatibility can be expected in L. saligna and L. virosa as well as in such taxonomically remote species as L. viminea, L. squarrosa and L. biennis. Other taxonomically remote species, i.e. L. dentata and L. alpina, exhibited a compatible reaction, although the reaction of the former was differential. A high level of sporulation was recorded in all accession/isolate interactions of L. alpina.
The Hydroxyproline Content in Cell Wall of Resistant and Susceptible Alfalfa Plants Inoculated with Wilt Pathogens
Authors: Krátká J. , Kürdela V. 
Published: May 2008

AbstractThe changes of hydroxyproline (Hyp) content in cell wall after inoculation with Corynebacterium michiganense pv. insidiosum or Verticillium albo‐atrum in 8 cultivars of alfalfa (Medicago sativa) were studied.In our experiments cultivars ‘Trek’ and ‘Vernal’– resistant, ‘Du Puits’ and ‘Vertus’– susceptible to C. michiganense;‘Vela’ and ‘Maris Kabul’– resistant to V. albo‐atrum, ‘Sabilt’ and ‘Lahontan’– susceptible to V. albo‐atrum were used.In resistant plants inoculated with C. michiganense none or a small increase of Hyp content in comparison with control plants was registered. On the other hand, inoculated susceptible plants showed markedly increase of Hyp content in comparison with the control plants.The differences in Hyp content between control and inoculated resistant and susceptible plants with V. albo‐atrum were not markedly expressed in comparison with the alfalfa –C. michiganense pair.The changes had similar tendency both in C. michiganense and V. albo‐atrum.–alfalfa pairs.
Colonization of Claviceps purpurea sclerotia on Triticale by Fusaria in 1985
Authors: Chelkowski Jerzy , Kwasna Hanna 
Published: May 2008

AbstractDuring 1985 60% of Claviceps purpurea sclerotia collected from Triticale heads were colonized by Fusarium acuminatum Ell. et Ev. and F. heterosporum Nees.
Effect of Source Strength, Distance and Direction on the Spread of Maize Dwarf Mosaic Virus
Authors: Madden L. V. , Knoke J. K. , Louie R. 
Published: May 2008

AbstractSpread of maize dwarf mosaic virus (MDMV) from infected maize to trap plants was assessed at 8 successive weeks. During each week, 0, 9 or 81 infected plants were placed in the centre of a fallow area. Ten trap plants each were placed at each of eight compass directions at three distances (8, 16 and 24 m) from the source. Disease incidence varied with week, distance and source strength (number of infected plants at the source). Disease increased to a maximum by 27 August, and then decreased. There was a decline in disease with distance from the source but no change in disease with direction. There was little disease in the controls or at 24 m in the other plots. Number and species composition of aphids also varied with time, and a few species were highly related to disease incidence.
Zur Auswirkung von Resistenzreaktionen auf Pflanzenwachstum und Ertrag in inkompatiblen Wirt‐Parasit‐Systemen
Authors: Schönbeck F. , Grunewaldt‐Stöcker G. , Wilde T. 
Published: May 2008

Abstract Effects of defense reactions on plant growth and yield in incompatible host‐parasite‐systems Investigations in incompatible host‐parasite‐systems (barley –Erysiphe graminis and lettuce –Bremia lactucae) were carried out to prove, whether the induction of defense reactions leads to measurable effects on the yield performance of plants. Permanent or frequent inoculations with avirulent races decreased yield of barley and lettuce remarkably, expressed in reduced fresh weight and drym, atter. Less grains were produced and their contents of carbohydrates and amino acids were diminished significantly. In young plants a reduction in sugar content was evident already after a single inoculation. In barley as in lettuce this effect was shown, not only for inoculated, but also for plant parts not present at the time of inoculation. There, in addition especially aromatic amino acids increased, while glutamate, aspartate and their amides diminished. The consequences of a permanent maintenance of postinfectional resistance mechanisms either of a hypersensitive or non‐hypersensitive reaction type for growth and yield performance are discussed with regard to an increased consumption of energy and carbohydrates.
Immunological Methods for the Detection of a Coryneform Isolated from Ratoon Stunted Sugarcane
Authors: Oellermann R. A. , Pillay D. 
Published: May 2008

AbstractA coryneform bacterium, isolated from ratoon stunted sugarcane, has been obtained in pure culture. Its identification by immunological means was investigated. Optimum conditions for the light microscopic observation of bacterial agglutination by specific antiserum, immunofluorescence and the microcapillary haemagglutination of IgG‐sensitized erythrocytes by the bacterium were established. All three assay procedures are simple and rapid. By comparison, more samples can be handled at any one time bythe microcapillary haemagglutination method. Based on bacterial agglutination, the antiserum is specific for the coryneform isolated from ratoon‐stunted sugarcane.
Comparison of a Filter Paper Immunobinding Assay, Western Blotting and an Enzyme Linked Immunosorbent Assay for the Detection of Wheat Streak Mosaic Virus
Authors: Sherwood J. L. 
Published: May 2008

AbstractThe adaptation and improvement of serological assays for the detection of plant viruses has steadily developed. A filter paper immunobinding assay, Western blotting and the double sandwich ELISA were compared for the detection and quantification of wheat streak mosaic virus. ELISA was a more quantitative assay, but the filter paper immunobinding assay and Western blotting were more conservative of antiserum when only a few assays were required and could be run in a shorter period of time.
The Development of an In Vitro Host‐Pathogen System Consisting of Maize Seedling Segments Infected with Ustilago maydis
Authors: Hausen G. , Beiderbeck R. 
Published: May 2008

AbstractThe nodal segments of 7‐day‐old seedlings of maize were inoculated with sporidia of Ustilago maydis. At different times after inoculation (day 0 to day 9), the nodal segments were explanted to tissue culture media containing Benomyl. On one of the media, segments explanted at day 1 or later responded with the formation of galls carrying roots. In such galls Ustilago could complete its life cycle and form teliospores. Explantation at day 0 never led to gall or teliospore formation. Thefindings are discussed with respect to the possible presence of mycoboethins.
Relation Entre la Teneur en Sucres Réducteurs des Tissus du Tournesol (Helianthus annuus L.) et leur Invasion par Macrophomina phaseolina (Tassi) Goid.
Authors: Davet P. , Serieys H. 
Published: May 2008

Abstract Relation between the amount of reducing sugars in sunflower tissues and their invasion by Macrophomina phaseolina (Tassi) Goid. Reducing sugars (R.S.) were measured with Bernfeld colorimetric method. In the roots, the amount of R.S. increased up to a maximum, then decreased from the beginning of flowering, and remained constant, at a very low level, from the outset of seed maturation. The same evolution was observed, with a delay of one week, in stem bases, but the amounts of R.S. were a little higher. Roots, and thereafter, stems, were invaded by Macrophomina phaseolina only after the minimum level of R.S.was reached.Varietal differences were observed, in a collection of sunflower hybrids, in response to invasion by M. phaseolina. R.S. levels in stem bases were higher in the resistant than in the susceptible hybrids.