bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of Rhizoctonia solani and Cotton Seedling Disease by Laetisaria arvalis and a Mycophagous Insect Proisotoma minuta (Collembola)
Authors: Lartey RobertT. , Curl E. A. , Peterson CurtM. , Williams J. C. 
Published: May 2008

Abstract Laetisaria arvalis and a mycophagous, rhizosphere‐inhabiting collembolan, Proisotoma minuta, were evaluated in sterilized and nonsterilized soil for suppression of Rhizoctonia solani in a greenhouse environment. R. solani was applied to soil at rates between 10 and 150 mg of colonizedoat inoculum/kg soil. L. arvalis was applied directly to soil at 100 mg/kg or as a seed dressing, either alone or in combination with a population of P. minuta at 1000/kg soil. L. arvalis significantly reduced incidence and severity of cotton seedling disease caused by R. solani; the seed treatment provided better suppression than when L. arvalis was applied to soil. Combination of the fungal agent with P. minuta enhanced suppression of R. solani more than with either agent used alone. Control benefit was linearly increased when increased numbers of insects were applied with L. arvalis.
Consecutive and Simultaneous Competition ELISA of Monoclonal Antibodies: Characterization of Epitope Relationships or Immunoglobulin Idiotypes
Authors: Kubanek C. A. , Hill J. H. , Van Deusen R. A. , Durand D. P. 
Published: May 2008

AbstractA panel of monoclonal antibodies prepared against cowpea severe mosaic virus was divided into two groups based upon presence or absence of competition with a biotinylated antibody in competition ELISA. Antibodies that did compete could be further characterized by comparison of competition curves obtained from assays performed in simultaneous and consecutive manners. These two types of competition assays provide an easy method to define intially relationships among epitopes on antigens and to characterize specific immunoreactivity of different antibodies to the antigen.
Biological Control Activity of Three Trichoderma Isolates Against Fusarium Wilts of Cotton and Muskmelon and Lack of Correlation with their Lytic Enzymes
Authors: Ordentlich A. , Migheli Q. , Chet I. 
Published: May 2008

AbstractThe enzymatic activity and the biocontrol ability of two new isolates of Trichoderma spp. (T‐68 and Gh‐2) were compared in laboratory and glasshouse experiments with a previously studied T. harzianum strain (T‐35). In dual culture tests with Fusarium oxysporum f. sp. melonis and F. oxysporum f. sp. vasinfectum, isolates T‐68 and Gh‐2 overgrew the colonies of Fusarium, whereas T‐35 failed to parasitize both wilt pathogens. Under glasshouse conditions, the three isolates of Trichoderma were effective in controlling Fusarium wilt of cotton but only T‐35 was effective against F. oxysporum f. sp. melonis on muskmelon. When the three Trichoderma isolates were grown on liquid media containing laminarin, colloidal chitin or F. oxysporum f. sp. melonis cell walls as sole carbon sources, maximum β‐1,3‐glucanase and chitinase specific activity in the culture filtrates of all fungi was reached after 72h of incubation. When culture filtrates of the three Trichoderma isolates were incubated with freeze‐dried mycelium of F. oxysporum f. sp. melonis or F. oxysporum f. sp. vasinfectum, different concentrations of glucose and N‐acetyl‐D‐glucosamine were released. Overall no correlation was found between enzymatic activity and the biocontrol capability against Fusarium wilt on muskmelon and cotton.
A Simulation Model for Assessing Soybean Rust Epidemics
Authors: Yang X. B. , Dowler W. M. , Tschanz A. T. 
Published: May 2008

AbstractA soybean rust (causal agent Phakopsora pachyrhizt) simulation model was developed for assessing disease epidemics as a part of pest risk analysis. Equations describing environmental effects on disease components were developed by re‐analyzing previous data with a view toward a systems approach. The infection rate was predicted well using dew period and temperature after inoculation as independent variables (R2=0.88, P < 0.0001). The exponential models which used physiological day as an independent variable explained 98% of the variations of latent period and senescence of disease lesions. The simulation model was validated with data from 72 sequential planting experiments during 1980 and 1981 in Taiwan. Time of onset for these epidemics varied from 25—60 days and 50—80 days after planting soybean cultivars TK 5 and G 8587, respectively. The epidemic periods were 75—95 for TK 5 and 100—120 days for G 8587. Variation of epidemics was accurately predicted by the simulator. Predicted disease curves fit well the observed disease curves for the recognized cropping seasons, spring‐ and autumn‐seeded crops. For G 8587, which is very sensitive to photoperiod, the data from spring and autumn gave a better fit compared with data from pre‐summer planting. The model underestimated disease epidemics during the winter, probably because the plant growth model failed to reflect the photoperiod rection of soybean. The simulation model was validated with data from other experiments conducted in three cropping seasons in 1979 and 1980. Determination coefficients of the regression between observed and predicted disease severity were significant.
The Effects of Temperature on the Susceptibility of Potato Plants to Infection and Accumulation of Potato Leafroll Virus
Authors: Syller J. 
Published: May 2008

AbstractTemperature both before and after aphid inoculation with potato leafroll virus (PLRV) greatly influenced the susceptibility of potato plants to infection and virus accumulation, as evaluated with ELISA using cultivars with different ratings for the resistance to PLRV. Pre‐incubation at 15 compared to 27 °C increased the susceptibility of plants to infection and a subsequent PLRV accumulation. The virus was detected by ELISA in a greater proportion of plants and reached a higher concentration, when the plants were kept at 27 than at 15 °C after inoculation. The mean ELISA values obtained with PLRV‐infected plants in the 15/27 combination of the pre‐/post‐inoculation temperatures over the period 1—6 wks after inoculation were significantly higher than those in the 27/27, 15/15 and 27/15 treatments, and the values obtained in the 27/27 treatment were significantly higher than those in the 15/15 and 27/15 ones. A hypersensitive‐like intolerance reaction to PLRV occurred in the resistant cv. Irga only in the plants kept at 27 °C after inoculation.
The Effect of Bacillus subtilis on in vitro Growth and Pathogenicity of Agrobacterium tumefaciens
Authors: Hassanein F. M. , El‐Goorani M. A. 
Published: May 2008

AbstractFive isolates of Bacillus subtilis isolated from the soil, were found to be antagonistic to 6 isolates of Agrobacterium tumefaciens in vitro.Inoculation of B. subtilis in wounded castor bean plants 30 min before or simultaneous inoculation with A. tumefaciens resulted in excellent control of the crown gall symptoms on the host within 50 days of inoculation.Application of B. subtilis 30 min after inoculation with A. tumefaciens did not result in appreciable disease reduction.Treatment of the tested plants by B. subtilis did not induce any phytotoxic injury or growth retarding side effects.It appears that B. subtilis could potentially be incorporated for crown gall control. However, further tests are needed to test this biological control agent with other plant species especially fruits, nuts and vine nursery stock.
Localization of Closteroviruses on Grapevine Thin Sections and Their Identification by Immunogold Labelling
Authors: Faoro F. , Tornaghi R. , Belli G. 
Published: May 2008

AbstractDifferent fixation and embedding procedures have been tested in order to facilitate closterovirus identification on thin sections of leafroll‐affected grapevine plants. Standard fixation with glutaraldehyde followed by osmium tetroxide proved to be the most reliable for cytopathological studies while simultaneous fixation with glutaraldehyde, picric acid and osmium tetroxide facilitated the discrimination between aggregates of P‐proteins and virus particles in routine e. m. work. However the identification of every single virion among P‐protein filaments was only possible by means of post‐embedding immunogold labelling carried out on non‐osmicated tissues embedded in London Resin White. This technique has also been applied to both section sides thus allowing the identification of different closteroviruses contemporaneously present in the same phloem tissue. Numerous ultrastructural observations of different grapevine cultivars infected with either GVA, or GLRaV‐I or GLRaV‐III evidentiated the presence of some recurrent and peculiar cytopathic effects that can be used as diagnostic parameters for at least two of the above viruses.
Pseudomonas syringae pv. syringae as One of the Factors Affecting the Ice Nucleation of Grapevine Buds in Controlled Conditions
Authors: Luisetti J. , Gaignard J. L. , Devaux M. 
Published: May 2008

AbstractIce nucleation in grapevine buds (cv. Pinot noir) was studied in freezing chamber in container grown plants. The ice nucleation of individual 278 buds at different stages of their development (between stage B and stage E according to Baggiolini scale) was measured by differential thermal analysis. Treatments were applied to plants to modify the Pseudomonas syringae pv. syringae content of buds and alter their water potential.Based on the results it was pointed out that (i) the ice nucleation temperatures of buds were generally normally distributed, (ii) the probability of bud nucleation at a given temperature was, to a certain extent, dependent on the amount of Pseudomonas present, (iii) the modification of water potential following an artificial rain led to a signification increase of the probability of bud nucleation and (iv) the nucleation probability did not increase significantly with the bud development between stage B and stage E.
Systemic Acquired Resistance to Virus Infections and Ethylene Biosynthesis in Asparagus Bean
Authors: Pennazio S. , Roggero P. 
Published: May 2008

AbstractSystemic acquired resistance (SAR) was induced in asparagus bean following inoculation with tobacco necrosis virus (TNV) or tobacco rattle virus (TRV), viruses that produce a hypersensitive reaction in this plant. SAR was expressed against challenge by TNV as reduction in lesion size, but not as inhibition of viral antigen accumulation.Systemic stimulation of ethylene‐forming enzyme (EFA) activity, in the absence of any ethylene increase or 1‐aminocyclopropane‐1‐carboxylic acid (ACC) accumulation, was associated with SAR. Formation of local necrotic lesions was necessary for both induction of SAR and stimulation of EFA, because early removal of inducer leaves prevented both events. SAR was expressed at rather constant level between 7 and 12 days after inducing infection. EFA stimulation declined with time and was no longer detected 7 days after inducing infection.SAR was not expressed against cucumber mosaic virus, that infect asparagus bean systemically. Prior inoculation with TNV or TRV was ineffective to reduce CMV antigen content or to minimize the pathogenic effect of this virus in systemically infected leaves.
Isozyme Variability in Isolates of Some Facultative Phytopathogenic Fungi
Authors: Newton A.C. 
Published: May 2008

AbstractGel electrophoresis was used to examine the variation in isozymes within and between the facultative pathogen species Septoria nodorum, Ustilago maydis and Rhynchosporium secalis. Variation was found in all three species, U. maydis being the most variable. The variation between isolates of R. secalis was sometimes unstable, reflecting variability in other characters. The determinants of isozyme variability, particularly in relationship to the general biology of different fungi, are discussed.
Immunocytochemical Evidence for the Presence of Barley Thionins in Rachis and Stalk of Wheat: Decrease of Antibody Binding at Fusarium culmorum Penetration Sites
Authors: Ebrahim‐Nesbat F. , Apel K. , Heitefuss R. 
Published: May 2008

AbstractIn thin sections of wheat rachis and stem, embedded in Spurr's resin, prefixed with glutaraldehyde and postfixed with osmium, large amounts of barley thionins were localized in cell walls with anti‐thionin‐protein A/gold. Reduced binding to thionin was detected in cell walls penetrated by Fusarium culmorum, suggesting that cell wall thionins were degraded by the fungus.
Barley Yellow Striate Mosaic Virus as the Cause of a Major Disease of Wheat and Millet in Iran
Authors: Izadpanah K. , Ebrahim‐Nesbat F. , Afsharifar A. R. 
Published: May 2008

AbstractBarley yellow striate mosaic virus (BYSMV) was identified in Iran by electron microscopy and serology. The virus was widespread in the Fars province causing mosaic, stunting and head sterility in wheat and mosaic symptoms in Setaria spp. In 1989, about 1/3 of wheat plants in the Bajgah Experiment Station, 15 km north of Shiraz, were infected. The yield in individual plants was drastically affected. Rhabdovirus particles were consistently observed in leaf‐dip preparations and thin sections from the infected plants. The virus was transmitted by Laodelphax stritellus to wheat. It reacted with BYSMV antisera from Italy and Morocco but not with antisera to several other rhabdoviruses of gramineous plants.
The Association of Peroxidase Activity and Resistance of Maize to Exserohilum turcicum
Authors: Shimoni M. , Bar‐Zur A. , Reuveni R. 
Published: May 2008

AbstractPeroxidase activity in leaves of maize (Zea mays L.) differing in susceptibility to Exserohilum turcicum has been investigated in relation to their resistance to Northern Leaf Blight (NLB) caused by the fungal pathogen E. turcicum. In non‐inoculated plants, high peroxidase activity was detected in leaves of the resistant isolines B37HtN and B73HtN as compared with the susceptible isolines B37 and B73 and the sweet corn variety Jubilee. After inoculation with E. turcicum, peroxidase activity increased in both susceptible and resistant isolines B73 and B73HtN. However, marked enhancement of peroxidase activity was detected 6 days after inoculation and became remarkable in isoline B73HtN, although symptomes started to show up in both susceptible and resistant plants only 10 days after inoculation.Using polyacrylamide gel electrophoresis separations, different banding pattern of isoperoxidases was found in the susceptible plants as compared with the resistant ones. In non‐inoculated plants, three differential bands which appeared in the resistant isoline B37HtN, were absent in the susceptible Jubilee plants, and were as traces in the isoline B37. These bands first appeared in Jubilee and as clear bands in B37, only after inoculation with E. turcicum. The association of these isoperoxidases and resistance of maize to E. turcicum is discussed.
Gehalt an Beet Necrotic Yellow Vein Virus (BNYVV) in der Hauptwurzel von Zuckerrübenpflanzen verschiedener Sorten und deren Leistung unter Rizomaniabefall im Feld
Authors: Bürcky K. , Büttner G. 
Published: May 2008

AbstractBNYVV concentration in the tap roots of sugar beet varieties grown in rhizomania‐infested fieldsDuring plant development, the BNYVV concentration in several commercially available rhizomania‐tolerant sugar beet varieties and one susceptible variety was examined as an index of the intensity of infection. The root weight, sugar content and sugar yield of the same varieties in fields naturally infested with rhizomania were also measured.Significant negative correlations were found between the average virus concentration in the tap root and yield parameters in infested fields. These were largely independent of the growth stage of beet plants used for virological investigations. However, the negative correlations between virus concentration and yield were not significant if rhizomania‐tolerant varieties only were compared.The possibility that virus concentration might be used as a criterion for selection in addition to yield performance is discussed. This may lead to selection that is targeted more directly at rhizomania resistance and thereby accelerate breeding work.
Variation in Pathogenicity and Virulence of Strains of Xanthomonas campestris pv. glycines, the Incitant of Bacterial Pustule of Soybean
Authors: Hokawat S. , Rudolph K. 
Published: May 2008

AbstractStandardized methods were developed to determine the pathogenicity and the degree of virulence of Xanthomonas campestris pv. glycines (Xcg) as well as the reaction of soybean plants in the greenhouse. A glass atomizer is described which allowed uniform inoculation without damaging the leaves. Optimum bacterial concentration was determined as 6 × 106 CFU/ml for the pathogenicity test and 1.3 × 105 CFU/ml for the virulence test. A total of 64 isolates were tested. Forty‐five strains were designated as pathogenic, six of which were considered highly virulent. It was shown, for the first time, that large differences in the virulence of Xcg strains exist.All the highly virulent strains of Xcg were fresh isolates from diseased soybean leaves collected in Thailand. On the other hand, all the “old” cultures from bacterial collections possessed a low or very low virulence. Decrease of virulence of the pathogen did not occur very fast, however, that is: not within 2 years when stored on YDC‐agar slants. Therefore, the bacteria may be kept on slants at 15 °C for short time storage, but the strains should be preserved permanently as lyophilized cultures.
Differential Reactions Between the Genus Brassica and Aggressive Single Spore Isolates of Leptosphaeria maculans
Authors: Badawy H. M. A. , Hoppe H.‐H. , Koch E. 
Published: May 2008

AbstractBased on sirodesmin production and pathogenicity tests with Brassica cotyledons, strains of Leptosphaeria maculans were classified as aggressive (pathotype group A), or non‐aggressive (pathotype group NA). NA strains caused no differential reactions. However, the pathotype group A could be divided into 5 sub‐groups. AO isolates caused non‐sporulating lesions with dark margins while Al isolates sporulated on cotyledons of most Brassica hosts tested. Only the cv. Erfurter Zwerg (B. oleracea var. botrytis) reacted resistant against AO and Al strains. A2 isolates caused resistance reactions on cotyledons of the cvs. Quinta (B. napus var. oleifera) and Runde (B. rapa var. rapa). A3 and A4 isolates were not detectable in our material. Isolates of these pathotype groups, supplied by Dr. P. H. Williams, Madison, USA, caused differential reactions on the oilseed rape cvs. Glacier, Quinta and Jet Neuf. In glasshouse and field experiments strains of pathotype groups Al, A2 and NA were tested on true leaves and hypocotyls of different oilseed rape cultivars. The low aggressiveness of NA isolates was evident under all experimental conditions. A2 strains caused resistance reactions not only on cotyledons but also on true leaves and hypocotyls of Quinta. Moreover, compared with Al, pathotype group A2 was more aggressive on hypocotyls of Jet Neuf. The resistance of this cultivar against Al isolates was clearly visible on hypocotyls and true leaves but not on cotyledons.
Susceptibility of Grafted Malus Taxa and Hybrids to Apple Proliferation Disease
Authors: Kartte Sylvia , Seemüller E. 
Published: May 2008

AbstractSeedlings of a great number of Malus species, subspecies, cultivars and hybrids were graft‐inoculated with the apple proliferation MLO. The scion cultivars were M. pumila cv.‘Cox's Orange Pippin’and‘Golden Delicious’. The grafted trees responded very differently to infection. According to recovery rate, witches’broom formation, mortality, and development of the MLO population, the tested material could be divided into 5 groups. Group I corresponds to the domestic apple M. pumila and is characterized by a low recovery rate, a low mortality, a high frequency of witches’broom formation, and a high MLO titer. Group II differs from group I mainly by a higher mortality. In group III, mortality is like in group II but recovery is higher while witches’broom formation and MLO titer are significantly lower. Group IV is characterized by a mortality of more than 50 %. Both witches’broom formation and the numbers of MLOs in the phloem are usually low. In group V, most of the trees recovered or showed never symptoms while mortality was low. After inoculation the MLO population was low or appeared degenerate. During recovery the number of MLO‐positive samples decrease so that by the end of the observation period the organisms could not longer be detected in most cases. Group V consists of apomictic rootstock selections deriving from crosses of M. sieboldii and M. sargentii with M. pumila. Due to the combination of low mortality with the apparent elimination of the MLOs within a few years this group fulfills the requirement of resistant rootstocks suitable for controlling apple proliferation.
Histopathology of Apple Proliferation in Malus Taxa and Hybrids of Different Susceptibility
Authors: Kartte Sylvia , Seemüller E. 
Published: May 2008

Abstract Malus taxa and hybrids (“taxa”) grafted with M. pumila cv.‘Golden Delicious’differ significantly in their susceptibility to apple proliferation which is caused by a mycoplasma‐like organism (MLO). These differences are correlated with the severity of anatomical aberrations and the numbers of MLOs in the phloem. The roots of declining trees of highly susceptible taxa with a mortality of more than 50 % are characterized by extensive phloem necrosis and the depletion of starch. MLOs are either not detectable or are present in low numbers, or the population appears degenerate when viewed by fluorescence microscopy. In comparable trees of a hybrid of M. sieboldii×M. pumila which shows a high recovery rate, both phloem necrosis and starch depletion are less pronounced, and the MLO numbers are low or the organisms are not detectable. Decline‐tolerant taxa such as M. silvestris or M. pumila×M. baccata are little affected. Their phloem conditions and starch content do not differ significantly from that of healthy trees. However, the MLO titer is high. The histopathology of the scion cultivar of all groups examined is rather similar to that of the roots of the decline‐tolerant taxa. Only in a late stage of decline, phloem necrosis increases while starch content and MLO numbers decrease in the scions grafted onto highly susceptible stockls.
Secretion of Extracellular Enzymes by Verticillium psalliotae Treschow and Verticillium lecanii (Zimm.) Viégas During Growth on Uredospores of the Soybean Rust Fungus (Phakopsora pachyrhizi Syd.) in Liquid Cultures
Authors: Saksirirat W. , Hoppe H.‐H. 
Published: May 2008

AbstractTwo isolates of the mycoparasite Verticillium psalliotae grew rapidly in liquid cultures on autoclaved uredospores of the soybean rust fungus (Phakopsora pachyrhizi Syd.) as sole carbon source and secreted β‐l,3‐glucanase, chitinase, and protease activities into the medium. One isolate of Verticillium lecanii grew slowly, failed to produce measurable chitinase activity and secreted lower specific activities of β‐l,3‐glucanase and protease, compared with V. psalliotae. The tested isolates of V. psalliotae and V. lecanii produced comparable levels of lipolytic activity. Amylolytic activity was secreted by V. lecanii but not by V. psalliotae. The isolates of V. psalliotae and V. lecanii used in our experiments differed clearly in protein and protease pattern, determined by electrophoresis on polyacrylamide gels. The results indicate that the rapid growth of V. psalliotae on autoclaved uredospores in liquid culture and on uredosori is probably based primarily on nutrients made available to the mycoparasite by activities of β‐1,3‐glucanases, chitinases and proteases.