bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Threshold Value for Cutting Intensity in Relation to Fusarium Root Rot of Red Clover (Trifolium pratense L.)
Authors: Rufelt S. 
Published: May 2008

AbstractAlthough cutting the foliage is known to increase Fusarium root rot severity in red clover (Trifolium pratense L.), no quantitative relationship has so far been determined. In this study, results from a number of greenhouse experiments, where plants were artificially inoculated with Fusarium avenaceum (Corda ex Fr.) Sacc., show a linear relationship between cutting intensity and Fusarium root rot in red clover, cv. ‘Hermes II’ an increased cutting intensity giving an increased root rot severity. Theoretically, a threshold value can be calculated beyond which no increase in root rot severity, compared to an uncut plant, should be expected.
Determination of Resistance or Susceptibility of Soybean Genotypes to Soybean Cyst Nematode, Heterodera glycines, Race 3
Authors: Al‐Jalili A. S. , Sapra V. T. , Pacumbaba R. P. 
Published: May 2008

AbstractResistance and/or susceptibility of several soybean genotypes to soybean cyst nematode (SCN), Heterodera glycines, race 3 was investigated. Three, 11, and 4 soybean genotypes were identified as resistant, moderately resistant, and susceptible, respectively. Resistant plants had fewer cysts on the roots and more root nodules, with the converse in susceptible plants. Reduction in yield of six extensively grown soybean cvs in Alabama was from 10 to 56% compared with the north Alabama average; resistant cv. ‘Bedford’ showed a yield loss of 10%. Cyst numbers were negatively correlated with nodule numbers and other agronomic characters. Nodules and other yield components were positively correlated except for non‐correlation of nodules and number of pods with plant height in the 1980 experiment.
A Method for Selection of Tolerance to African Cassava Mosaic Virus
Authors: Pacumbaba R. P. 
Published: May 2008

AbstractDetopping hastened the appearance of mosaic symptoms in shoots of cassava cuttings infected with African cassava mosaic virus (ACMV). The degree of plant recovery from severe mosaic after each detopping was the basis for evaluation of ACMV tolerance. In field‐screening, detopping of cassava shoots infected with ACMV is recommended for selection of tolerance to the virus. One detopping of ACMV‐infected shoots was sufficient to analyze tolerance level reliably. Out of 521 lines only one was found tobe tolerant, while 144 lines were found to be moderately tolerant. These included the lines ‘Gimbi MA 235’, (02945S × 3119)S MA 219, and ‘Kadanga Malombe’ previously described as resistant to ACMV.
Vergleich eines “glatten” und eines “rauhen” Stammes von Pseudomonas syringae pv. phaseolicola
Authors: Gerwe P.‐G. , Rudolph K. , Köhn S. 
Published: May 2008

AbstractComparison of a “smooth” and a “rough” isolate of Pseudomonas syringae pv. phaseolicolaThe “smooth” (S) wild strain of Pseudomonas syringae pv. phaseolicola was compared with a “rough” (R) variant of low virulence. Both strains grew nearly equally well on a sucrose containing medium with yeast extract and casamino acids, and the strains did not differ markedly in the quantity of produced EPS (= extracellular polysaccharides). Principally the same results were obtained for high and medium concentrations of sucrose, or when sucrose was replaced by glucose or fructose. However, on glucose and fructose considerably lower quantities of EPS were produced.The biological activity of S‐EPS was higher than that of R‐EPS. This difference between the EPS preparations was not as marked as leaf inoculation with both bacterial isolates. After prolonged bacterial culture the EPS‐production increased further, so that the differences between both strains decreased.A different EPS type was produced on the glycerol containing medium of KING B. Variations in the composition of this medium resulted in different morphology of the agar grown cultures, and the relative differences between S and R bacteria changed.When 62 different physiological tests for both bacterial strains were compared, the “rough” bacteria revealed a lowered range of positive reactions, with a few exceptions. However, it appeared unlikely that the reduced virulence of the “rough” bacteria was due to these differences. Obviously, defects in the extracellular products, but not in levan, were responsible for the reduction of virulence.
Mycorrhizal Fungi Prevent Disease in Stressed Pine Seedlings
Authors: Chakravarty P. , Unestam Torgny 
Published: May 2008

AbstractThe common rhizospheric fungus Cylindrocarpon destructans caused severe root damage leading to mortality in light‐starved, stunted seedlings of Pinus sylvestris. This effect was, however, almost fully prevented by the presence of mycorrhizal fungi; i.e. Laccaria laccata, Pisolithus tinctorius, or unidentified species present in small amounts of conifer soil. Protection took place even before visible mycorrhizae were found on the roots. This is the first time that protection ofstressed plants against non‐parasitic (non‐invasive) pathogens has been reported. The results indicate that root protection by mycorrhizal fungi may not only be effective inside the root but probably also extends out into the rhizoplane or rhizosphere.
Characterization of Caper Latent Virus
Authors: Gallitelli D. , Di Franco A. 
Published: May 2008

AbstractA virus with filamentous particles c. 662 nm in length, distantly serologically related to HelVS was isolated from caper (Capparis spinosa) in Southern Italy and characterized as a member of the carlavirus group. Virus particles have asedimentation coefficient of 168 S and a buoyant density in CsCl of 1.31 g × cm−3. They are constituted by a single protein species with a molecular weight of 35.700 which encapsidates a single species of single stranded RNA with the apparent size of 9100 nucleotides. This RNA was infectious constituting the whole viral genome. Virus particles either scattered or in aggregates but no specific cytopathological alterations were seen in infected cells. This carlavirus proved to infect caper symptomlessly and was often isolated in nature from plants without apparent signs of infection. For this reason, the name of caper latent virus (CapLV) is suggested for it. It is also suggested that CapLV be identical with caper vein banding virus, a tentative, member of the carlavirus group superficially described in 1970 from Southern Italy.
Biological Control of Phoma and Pythium Damping‐Off of Sugar‐Beet with Pythium oligandrum
Authors: Walther D. , Gindrat D. 
Published: May 2008

AbstractFlooding freshly harvested oospores in sterile distilled water (SDW) for several days enhanced germination in 3 out of 4 isolates of Phythium oligandrum. Treatment of SDW‐flooded oospores with myo‐inositol increased germinability during the first 20 days of storage at 15°C. Seed dressing with oospores of P. oligandrum controlled pre‐ and post‐emergence damping‐off of sugar‐beet caused by soil‐borne P. ultimum and seed‐borne Phoma betae. For some isolates, flooded oospores in SDW and treatment with myo‐inositol increased efficacy of the seed dressing. However, no significant control of damping‐off caused by Rhizoctonia solani was observed.On corn‐meal agar, P. oligandrum coiled around and penetrated hyphae of P. ultimum and R. solani, but did not interfere with Ph. betae.
Detection of Avocado Sunblotch Viroid in Spain by Double Polyacrylamide Gel Eletrophoresis
Authors: López‐Herrera C. , Pliego F. , Flores R. 
Published: May 2008

AbstractAvocado sunblotch viroid (ASBV) was detected in samples of young leaves and flowers of the avocado cultivars ‘Hass’ and ‘Fuerte’ grown in southern Spain. Partially purified nucleic acid preparations, obtained by cellulose chromatography, were analyzed by double polyacrylamide gel electrophoresis. This technique, consisting of two consecutive electrophoresis cycles under nondenaturing and denaturing conditions, followed by silver staining of the gel, allowed the selective and sensitive identification, of ASBV. This is the first report on the occurrence of the causal agent of avocado sunblotch in Spain.
Soil Suppressiveness to Fusarium Wilt of Melon, Induced by Repeated Croppings of Resistant Varieties of Melons
Authors: Sneh B. , Pozniak D. , Salomon D. 
Published: May 2008

AbstractA field soil, artificially infested with pathogenic isolates of Fusarium oxysporum f. sp. melonis was continuously used for screening resistant varieties of melon to Fusarium wilt. After 9–10 years of continuous cropping with resistant varieties, the soil had developed induced suppressiveness. Seven to 9 experimental replantings of the induced suppressive soil with the susceptible cultivar of melon, ‘Ein‐Dor', nullified its suppressiveness. This was expressed by 90 % disease incidence. Only 2 replantings were required to obtain the same disease incidence in an adjacent field of a conducive soil. Nonpathogenic isolates of F. oxysporum, isolated from the rhizospheres of melon seedlings, induced various degrees of soil suppressiveness when added to soil at various ratios to the pathogenic isolate.
Ultrastructure and Development of Sclerotia of Botrytis cinerea Pers. in vitro
Authors: Nair N. G. , Martin A. B. 
Published: May 2008

AbstractThe development of sclerotia of Botrytis cinerea was examined at four stages during their maturation. The surface structure developed a network of profusely branched hyphae through their coalescence to a compact sclerotial body which was maturated by the deposition of melanin pigment.A characteristic feature of the hyphal cells of B. cinerea during the later stages of development was the presence of paramural bodies (plasmalemmasomes and lomasomes). Electrondense bodies with a limiting double‐membrane congregated against the transverse septa of hyphal cells as sclerotia matured and may migrate from cell to cell through septal pores. We suggest that these and the lipid bodies found in hyphal cells may have a storage function in the resting sclerotia.
Tetracycline Therapy of Clove Trees affected by Sudden Death Disease in Zanzibar
Authors: Dabek A. J. , Martin P. J. 
Published: May 2008

AbstractRepeated trunk injections of tetracycline hydrochloride and oxytetra‐cycline over a 27 month period, retarded the rate at which clove trees in Zanzibar, died from sudden death (SD) disease. This result provides additional support for an MLO aetiology for SD, but indicates that the tetracycline formulations and method of application, as described here, is not a feasible method of SD control in the field. Bioassay of leaf discs and root sections using agar plates seeded with Bacillus subtilis, at various times after injection, indicated that antibiotic distribution to the canopy was extensive, but that down to the roots was minimal. The proportion of leaf discs showing tetracycline activity declined over a 54 day period post‐injection, from 75,% to 17%. Mean tetracycline levels in leaves per tree peaked at 2.4 μg/ml, 21 days after injection. The highest individual leaf disc level was 7 μg/ml. Most trees maintained concentrations of tetracycline inhibitory to B. subtilis growth for 2,1–41 days.
Isolation and Characterization of a Geminivirus Causing Yellow Mosaic Disease of Horsegram (Macrotyloma uniflorum [Lam.] Verdc.) in India*
Authors: Muniyappa V. , Rajeshwari R. , Bharathan N. , Reddy D. V. R. , Nolt B. L. 
Published: May 2008

AbstractHorsegram yellow mosaic disease was shown to be caused by a geminivirus; horsegram yellow mosaic virus (HYMV). The virus could not be transmitted by mechanical sap inoculation. Leaf dip and purified virus preparations showed geminate virus particles, measuring 15‐18 * 30 nm. An antiserum for HYMV was produced and in enzyme‐linked immunosorbent assay (ELISA) and immunosorbent electron microscopy (ISEM) tests HYMV was detected in leaf extracts of fieldinfected bambara groundnut, french bean, groundnut, limabean, mungbean, pigeonpea and soybean showing yellow mosaic symptoms. Bemisia tabaci fed on purified HYMV through a parafilm membrane transmitted the virus to all the hosts listed above but not to Ageratum conyzoides, okra, cassava, cowpea, Croton bonplandianus, Lab‐lab purpureus, Malvastrum coromandalianum and tomato. No reaction was obtained in ELISA and ISEM tests between HYMV antibodies and extracts of plants diseased by whitefly‐transmitted agents in India such as A. conyzoides yellow mosaic, okra yellow vein mosaic, C. bonplandianus, yellow vein mosaic, M. coromandalianum yellow vein mosaic, tomato leaf curl and cassava mosaic. HYMV was also not found to be related serologically to bean golden mosaic, virus.
Production and Regeneration of Protoplasts from Pseudocercosporella herpotrichoides (Fron) Deighton
Authors: Hocart M. J. , Lucas J. A. , Peberdy J. F. 
Published: May 2008

AbstractThis paper describes the development of a system for protoplast isolation from this pathogen using the commercially available, hydrolytic enzyme preparations Rhozyme HP150, Driselase and Cellulase CP. An analysis of the active components of these enzymes believed to be involved in protoplast release has been made. Factors affecting protoplast release including mycelial age, enzyme concentration and choice of osmotic stabilizer have been optimised, and conditions for high frequency protoplast regener, ation have been determined. The possible significance of the interaction of the several components of each enzyme is discussed. The developments described in this paper can now be exploited in genetic studies in this imperfect fungus.
Studies on the Extracellular Polysaccharides (EPS) Produced in vitro by Pseudomonas phaseolicola
Authors: Gross M. , Rudolph K. 
Published: May 2008

AbstractNative EPS produced by Pseudomonas syringae pv. phaseolicola in vitro was separated by ion exchange chromatography on DEAE fractogel into three different polysaccharide fractions.A neutral polysaccharide eluting with the void volume yielded only fructose upon hydrolysis and exhibited an IR spectrum similar to authentic levan. At about 300 mM KCl a mannuronan eluted. Comparison with authentic alginate by IR spectroscopy, elution behaviour during DEAE‐fractogel column chromatography, and monomer composition (mannuronic acid and traces of guluronic acid) confirmed the identity of this fraction as a bacterial alginate. It contained about 56 mol% acetyl groups. A third polysaccharide eluted at about 160 mM KCl. Its monomeric composition (rhamnose, fucose, glucose, and amino sugars), elution behaviour upon DEAE‐fractogel column chromatography, and TLC patterns, closely resembled the sugar moiety of lipopolysaccharides (LPS) from, Pseudomonas syringae pv. phaseolicola.The protein component of crude EPS represented a fourth macromolecular fraction. It was not covalently linked to any of the polysaccharides since it could be removed from the EPS by phenol extraction.
Individual and Combined Effects of Certain Pesticides on Rhizoctonia solani, Sheath Blight Pathogen of Rice
Authors: Singh U. D. , Sethunathan N. 
Published: May 2008

AbstractThe effect of different pesticides (fungicide, herbicide and insecticide) on the mycelial growth and formation and germination of sclerotia of sheath blight pathogen of rice, Rhizoctonia solani Kühn was studied in nutrient medium and in natural soil. Among the herbicides and insecticides, fenitrothion (insecticide) and thiobencarb (herbicide) were the most effective in inhibiting the mycelial growth and sclerotial formation. These pesticides effected significant inhibition of both mycelialgrowth and sclerotial formation at 7.5 to 10μg/ml concentration while fungicides carbendazim and tolclofosmethyl effected almost complete inhibition at 2.5 μg/ml. Interestingly, a synergistic increase in the toxicity to mycelial growth, sclerotial formation and sclerotial germination was noticed when the fungicide, mancozeb and the herbicide, thiobencarb were applied at subtoxic concentration in combination. Such synergistic interactions between pesticides in a combination leading to increased toxicity suggest that under the current practice of applying fungicides, herbicides and insecticides either simultaneously or in rotation, certain combinations may help in reducing the dose of a fungicide in disease control.
Interaction of Apple Cultivars with Populations of Cedar‐Apple Rust
Authors: Korban S. S. , Chen H. , Ries S. M. 
Published: May 2008

AbstractFive physiological populations of Gymnosporangium juniperi‐virginianae Schw. were identified on the basis of pycnial and aecial lesion formation when seven apple cultivars grown in a glasshouse were inoculated with basidiospores of rust populations collected from six locations in the U.S.A. The relationship between cultivars and rust populations was explored quantitatively using the parameters N, D, and DR, where N was the highest number of pycnial lesions on a leaf/plant; D was the largestdiameter measurement of pycnial lesions on a leaf/plant; and DR, the disease rating, was proportional to the diseased area of the leaf and calculated as ND2. Statistically significant differences among cultivars over all rust populations for variables N, D, and DR were obtained, indicating the possible existence of race non‐specific resistance in apple to cedar‐apple rust. Moreover, significant differences among the rust populations over all cultivars for variable N and DR were obtained, confirming the existence of physiologically different rust populations of the pathogen. A change in the pathogenicities of these physiological populations must have occurred over time (10‐year period). A significant interaction between cultivars and rust populations was observed for lesion size (D) only, indicating a probable existence of race specific resistance in apple as well.
Components of Resistance to Bacterial Blight Disease of Rice
Authors: Nayak P. , Rao A. V. Suriya , Chakrabarti N. K. 
Published: May 2008

AbstractStudies on the genetic variation, correlation, correlated response and path analysis were conducted on 8 rice cultivars to bring out the association and channelling of the pathway of different components of resistance to Xanthomonas campestris pv. oryzae. High genotypic coefficient of variation coupled with high heritability and genetic gain was observed for lesion size (LS) and the area under disease progress curve (AUDPC) indicating the predominance of additive gene effects. There was a strong association among all the components both at genotypic and phenotypic levels. Genotypic correlations were higher than the corresponding phenotypic correlations indicating the modifying effect of environment on association of components at genotypic level. Maximum correlated response and relative selection efficiency on AUDPC was observed through indirect selection for LS followed by the number of bacteria per unit leaf area (NB). Path analysis revealed highest direct effect of LS on AUDPCboth at genotypic and phenotypic levels. Indirect effects of fairly high magnitude were also exerted by incubation period (ICP) and NB towards AUDPC.
Purification of Phytohaemagglutinins from Phaseolus vulgaris and their Interaction with Plant Pathogenic Bacteria
Authors: Castresana M. C. , Serra M. T. , Tejerina G. 
Published: May 2008

AbstractErythrocytes and different strains of plant pathogenic bacteria agglutinated with aqueous and saline 1M NaCl extracts from Phaseolus vulgaris L. seeds, which showed similar gel electrophoretic patterns of proteins.Haemagglutinating activity in aqueous extracts was inhibited by some carbohydrates, especially N‐acetyl‐D‐galactosamine, D‐galactose and lactose. The agglutinin in this extract was purified by utilizing its ability to bind to Pseudomonas pisi cells followed by its removal from the bacteria by 0.3M galactose.Mitogenic activity of purified agglutinin was calculated as incorporation of 125I‐iododesoxy‐uridine into DNA of lymphocytes in vitro, which gave values between 25 and 50 μg/ml. The molecular weight of the subunits was found to be 31,500, estimated by mobility in SDS‐PAGE.A solid phase competition‐binding radioimmunoassay for bean agglutinin was developed in order to determine the affinity of this lectin in bean plants to phytopathogenic bacteria. The highest level of affinity was associated with the system formed by, Ps. pisi and lectin from fresh seeds.
Analysis of Virulence in Populations of Wheat Powdery Mildew in Europe
Authors: Limpert E. , Felsenstein F. G. , Andrivon D. 
Published: May 2008

AbstractRandom samples of spores of wheat powdery mildew were collected from the atmosphere by means of a jet spore sampler while driving through selected wheat growing areas in Europe in 1986. Their single colony progenies were tested in the laboratory forvirulence against wheat differential varieties with powdery mildew resistances Pm2, Pm4b, Pm8, Mli and the combinations Pm2+Pm6, Pm4b+Pm8 and Pm2+Pm4b+Pm8. There were regional differences in virulence frequencies. Virulence on Pm2, Pm2+Pm6 and, less expressed, on Pm4b was most frequent in England and decreased mainly to the east, whereas the reverse was true for Pm8. Virulence to Mli was generally high, and to the combined genotypes generally low. The results suggest that large parts of Europe are an epidemiological unit. The data are discussed with respect to selection caused by the varieties grown, as well as to the influence of wind distribution on the composition of the pathogen population.
Demonstration of Levan and Alginate in Bean Plants (Phaseolus vulgaris) Infected by Pseudomonas syringae pv. phaseolicola
Authors: Gross M. , Rudolph K. 
Published: May 2008

AbstractA simple method for the extraction of extracellular polysaccharides (EPS) from plant tissue was developed. The polysaccharides of bacterial and plant origin present in the crude leaf extracts were separated by column chromatography on DEAE‐fractogel, and the bacterial polymers were identified by IR spectroscopy.In extracts from infected leaves as well as in exudates (ooze) from leaf axils, alginate (an acetylated mannuronan) and levan (β‐2,6‐fructofuranan) were detected as the major components amounting up to 80% of the crude extracts. A race‐1 isolate of P. phaseolicola synthesized both levan and alginate in about equal amounts in planta, whereas a race‐2 strain produced EPS composed almost solely of alginate.Extraction of healthy leaves yielded low amounts of complex polysaccharides. These consisted mainly of galactose, arabinose, and galacturonic acid. Neither fructose nor mannuronic acid were detected.Kinetic studies indicated that the main production of bacterial EPS in planta was correlated with the appearance of the water‐soaked symptom in leaves. However, before water‐soaking became apparent, alginate was detected in infected leaves (1, day after inoculation). The high amount of extractable material (ca. 50 mg levan plus alginate per g of dry weight of diseased tissue) suggests that the bacterial EPS is responsible for the typical water‐soaked appearance of lesions after bacterial infection.Since alginate was predominantly synthesized by the more virulent race‐2 isolate, this component of bacterial EPS was suspected to be a decisive factor of virulence of P. phaseolicola. A possible function of alginate during pathogenesis is discussed.
Observation of Flagellate Protozoa (Phytomonas sp.) in Cocos nucifera, Cecropia palmata and Euphorbia hirta
Authors: Leeuw G. T. N. De , Kastelein P. 
Published: May 2008

AbstractTrypanosomatid flagellates (Phytomonas sp.) were detected in the sieve tubes of ‘hartrot'‐diseased coconut palms (Cocos nucifera) and in the laticifers of Cecropia palmata and Euphorbia hirta plants occurring as weeds in and around coconut plantations with diseased palms. The possible interrelationship and transmission by insect vectors of these protozoa is discussed.