bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility of Cut Rose Flower Cultivars to Infections by Different Isolates of Botrytis cinerea
Authors: Pie K. , Brouwer Y. J. C. M. 
Published: May 2008

AbstractA method was developed for the inoculation of flowers of cut roses with conidia of Botrytis cinerea. Flower buds were inoculated by spraying of conidial supensions that were ultrasonicated for 10 s. The differences in susceptibility between 8 rose cvs to infections of isolate Bc‐33 and the differences in pathogenicity between 14 5. cinerea isolates to cv. ‘Sonia’ were evaluated. Isolates obtained from rose flowers caused higher infection rates than those obtamed from various other hosts. The CVS ‘Madelon’, ‘Melody’ and ‘Sonia’ were found to be highly susceptible, whereas the cvs ‘Caramboie’, ‘Gabriella’, ‘Pasadena’ and ‘Rubinette’ were only slightly susceptible. The lower disease severity in the less susceptible cvs was based on a retardation of the growth of mfection hyphae in the petals, which may have been due to partial resistance. The formation of symptoms is effectuated already by the initial stages in the infection process. Thus, the apparent existing partial resistance to infections of B. cinerea cannot prevent the loss of ornamental value.
Systemic Infection of Tobacco by Pepper Veinal Mottle Potyvirus (PVMV) Depends on the Presence of Potato Virus Y (PVY)
Authors: Marchoux G. , Delecolle B. , Selassie K. Gebre 
Published: May 2008

AbstractIn single inoculations, both PVY and PVMV replicated in inoculated leaves of Nicotiana tabacum cv. ‘Xanthi nc’ plants, but only PVY infected the tobacco plants systemically, whereas PVMV caused localized infection.A mixed infection by the PVY‐To72 and PVMV‐type strains was experimentally realized in ‘Xanthi nc’ plants. In the presence of PVY, PVMV migrated systemically into the upper leaves of the tobacco plant, as was proved by back inoculation.It would appear that in tobacco, PVY acts as a “helper” virus, providing PVMV with the necessary component factor for migration.In extracts from the co–infected leaves. Immune Electron Microscopy (IEM) revealed phenotypic mixed particles which contained a mixture of coat proteins of PVY and PVMV.The role of the structural and functional interactions between the two viruses, which enable PVMV to migrate systemically in tobacco plants, is discussed.
Variation of Cell‐free Translation Profiles Among Pathogenic Strains of Soybean Mosaic Virus
Authors: Mansky L. M. , Durand D.P. , Bailey T. B. , Hill J. H. 
Published: May 2008

AbstractCell‐free translation products from isolates representing soybean mosaic virus (SMV) strains G1 to G7 and G7a, along with several other SMV isolates, were analyzed. SMV RNAs were translated in both rabbit reticulocyte lysates and wheat germ extracts, yielding approximately 20 translation products for each strain from each translation system. Comparison of translation profiles by the presence or absence of proteins allowed for the formation of distinctive groups from each cell‐free translation system. Groupings formed by analysis of products from rabbit reticulocyte lysates correlated with pathogenicity; groupings formed by analysis of products from wheat germ extracts had no apparent biological significance.
Effect of Microdochium nivale and Low Temperature on Winter Survival of Perennial Ryegrass
Authors: Prończuk Maria , Zagdańska Barbara 
Published: May 2008

AbstractWinter survival of perennial ryegrass (Lolium perenne L.) depends mainly on the plant resistance to low freezing temperature and to snow mould fungi (Microdochium nivale). Field evaluation of these plant characters gave irreproducible results. A comparison of field trials with laboratory tests pointed to the close correlation between the yield level of examined varieties and strains and their resistance to Microdochium nivale and frost. A lack of correlation between snow mould resistance and frost tolerance was shown.
Production and Use of Monoclonal Antibodies to Pseudomonas andropogonis
Authors: Li Xiang , Wong W. C. , Hayward A. C. 
Published: May 2008

Abstract Pseudomonas andropogonis is an important pathogen of worldwide distribution in ornamental and other plant species from 15 families. This paper reports the production and characterization of monoclonal antibodies (MAbs) to P. andropogonis and evaluation of their use in the detection of the pathogen in carnation cuttings. Ten stable hybridoma cell lines were produced. Results of indirect ELISA and indirect immuno‐fluorescence showed that MAb 6B3 was specific for P. andropogonis; MAb 3D5W1 reacted with both P. andropogonis and P. caryophylli; six other MAbs reacted with all strains of seven species of rRNA group II pseudomonads tested except P. solanacearum and P. pickettii. Eight of the ten MAbs failed to cross‐react with other non‐fluorescent or fluorescent pseudomonads, xanthomonads and other bacteria tested. P. andropogonis was similar in protein profile to other rRNA group II pseudomonads tested except P. solanacearum and P. pickettii. Epitopes were clearly located within the cell by immunogold labelling. Of four MAbs that were isotyped, two possessed IgGl and two the IgM heavy chain. P. andropogonis was readily detected by combining immunofluorescence and detached carnation leaf assay using an initial inoculum of 4 × 10° colony forming units (cfu) ml−1 after enrichment at room temperature for 4 days.
Physiological Responses of Tomato Plants Grown in Fusarium Suppressive Soil
Authors: Tamietti G. , Ferraris L. , Matta A. , Abbattista Gentile I. 
Published: May 2008

AbstractTomato plants grown in a Fusarium wilt suppressive soil and in the same soil steamed and amended with non‐pathogenic Fusarium strains were protected from subsequent infection with Fusarium oxysporum f. sp. lycopersici.Protected plants had higher laminarinase, chitinase, N‐acetyl‐glucosaminidase and β‐l, 4‐glucosidase activity than unprotected plants grown in steamed unamended soil. Higher peroxidase and polyphenoloxidase activity and higher content of phenols were also associated with suppressive soil conditions, although in a less consistent way.Among 5 non‐pathogenic Fusarium strains, strain 5a1 was the most suppressive and enhanced enzyme activity more than did the other strains, whereas strain T was inactive and did not induce changes in activity.These results are in accordance with previous work showing that induced resistance is associated with enhanced activity of glycosidases and phenol oxidizing enzymes, and increased phenols content. It is suggested that induced resistance is part of the mechanism of the natural suppressiveness of soil and that this resistance is induced by non‐pathogenic Fusarium strains.
Cross‐reactive Antigens between Xanthomonas campestris pv. citri Pathotypes and Citrus Species
Authors: Bach Erna E. , Alba Aluisio P. C. 
Published: May 2008

AbstractCross‐reactive antigens were detected in crude and semi‐purified preparations from acetone powder of Citrus aurantifolia and Citrus sinensis leaves with antisera to Xanthomonas campestris pv. citri pathotypes A and C by DAS‐ELISA. Antiserum to X. campestris pv. citri pathotype C revealed an antigenic disparity between C. aurantifolia (susceptible host to pathotype C) and C. sinensis (resistant host to pathotype C) whereas antiserum to X, campestris pv. citri pathotype A did not reveal any antigenic disparity between these hosts, both susceptible to pathotype A. The occurrence of “key” cross‐reactive antigens in Citrus species and X. campestris pv. citri and their possible involvement in such interaction are discussed.
Effect of Coronatine on Plant Cell Cultures
Authors: Perner B. , Schmauder H.‐P. 
Published: May 2008

AbstractThe effect of the phytotoxin coronatine, formed by pathovars of Pseudomonas syringae, on the plant cell cultures of Lycopersicon peruvianum, Lycopersicon esculentum, Chenopodium album and Solanum tuberosum was investigated. The parameters studied were growth, triphenyltetrazolium chloride activity (test for reductases), cell protein content and activities of polyphenol oxidase and peroxidase, both within the cells and in the culture liquid. The cultures of Lycopersicon peruvianum and Lycopersicon esculentum cultures were more sensitive than Chenopodium album and Solanum tuberosum. The more resistant cultures possess a high level of extracellular polyphenol oxidase.
Cellular Fatty Acid Composition of Nine Pathovars of Xanthomonas campestris
Authors: Wells J. , Civerolo E. , Hartung J. , Pohronezny K. 
Published: May 2008

AbstractCellular fatty acids of 80 strains of Xanthomonas campestris, representing 9 different pathovars, were analyzed by gas‐liquid chromatography and mass spectrometry. A total of 48 fatty acids were identified, the most important being the 16:0 (averaging at least 4.5 % of the total), the cis‐ and trans‐ 9 16 : 1 (over 14.4 %), and the iso and anteiso 15 : 0 (over 30 %). Other major fatty acids (averaging over 1 % of total) were the saturated 14 : 0 and 15 : 0, the hydroxy‐substituted iso 3‐OH 11 : 0, 3‐OH 12 : 0 and iso 3‐OH 13 : 0, and the branch‐chained iso 11 : 0, iso 16 : 0, iso 17 : 1, iso 17 : 0 and anteiso 17 : 0. Of 33 minor fatty acids detected and identified, only 7 have been previously reported in the xanthomonads. Significant differences in mean percentages of 5 major fatty acids and 4 (chemical) class totals were detected among pathovars, which statistically segregated into three groups by rank analysis. X. campestris pv. dieffenbachiae was in a group by itself; pvs. campestris, citri (pathotypes A and B), manihotis, phaseoli, pruni and vesicatoria were in a seond group, and pvs. glycines, begonia and citri (pathotype E) were in a third.
Aggregation of Colletotrichum acutatum in Response to Simulated Rain Episodes
Authors: Madden L. V. 
Published: May 2008

AbstractThe influence of rain splash dispersal on the aggregation and variability of spores of Colletotrichum acutatum, the causal agent of strawberry anthracnose, was studied with simulated rain over a soil surface. In the first experiment, rains with intensities of 15 and 30 mm/h were generated and sampling plates, with a selective medium for Colletotrichum, were positioned under rainshields at both 20 and 60 cm from an inoculum point source (five infected fruit) for 1‐min exposure periods. Number of colonies growing in plates were used to measure spore density. For each distance, time, rain intensity, and replication, the mean (m), variance (v), and Lloyd's index of patchiness (LIP) were calculated. Estimated (LIP) exceeded 1, indicating the high variability and clustering of colonies, and hence spores, resulting from splash dispersal. LIP increased with distance from the source and with rain intensity at the greater distance. Aggregation was further quantified by Taylor's power law describing the linear relation between ln (v) and ln (m). The slope (b) of the relation for all data points was 1·67, which was significantly (P < 0·01) greater than 1, a further indication of clustering. Distance form the source had a slight positive effect on b. Colony means (Y) were transformed to Y*=Y1/5 based on an approximate b of 1·6. Analysis of Y* indicated an expected significant main effect of rain duration and a significant interaction of distance and rain intensity. In another experiment, six infected fruit and the sampling plates were uniformly placed over the surface. LIP again exceeded 1, and Taylor's b equaled 1·63. In a final study, the inoculum source and sampling plates were raised 46 cm above the soil surface. There was a drastic reduction in Y* compared to surface values, supporting the prior hypothesis that surface topography strongly affects splash dispersal. Results indicate that the physical process of splash dispersal produces a degree of aggregation similar to that produced by population dynamic and other ecological processes.
Use of Rhizobia in the Control of Root Rot Diseases of Sunflower, Okra, Soybean and Mungbean
Authors: Ehteshamul‐Haque Syed , Ghaffar A. 
Published: May 2008

AbstractBiocontrol potential of Rhizobium and Bradyrbizobium against soilborne root infecting fungi was tested. In vitro tests Rhizobium meliloti inhibited growth of Macrophomina phaseolina, Rhizoctonia solani and Fusarium solani while Bradyrhizobium japonicum inhibited M. phaseolina and R. solani producing zones of inhibition. In field R. meliloti, R. leguminosarum and B. japonicum used either as seed dressing or as soil drench reduced infection of M. phaseolina, R. solani and Fusarium spp., in both leguminous (soybean, mungbean) and non‐leguminous (sunflower and okra) plants.
Ultrastructure of Tobacco Ringspot Virus‐Induced Local Lesions in Lima Bean Leaves
Authors: White J. A. , Sehgal O. P. 
Published: May 2008

AbstractTobacco ringspot virus (TRSV), a nepovirus, induced unusually large, expanding lesions in the primary leaves of lima bean (Phaseolus lunatus cv. Nemagreen). During the course of lesion development, two phases were identified on the basis of ultrastructural observations. In the primary phase, cytological changes followed a pattern that was characteristic of compatible or systemic nepovirus infections. Such changes included the formation of large, membranous inclusion bodies in the cytoplasm of mesophyll parenchyma and the accumulation of phytoferritin in the stroma of chloroplasts. The cells maintained their structural integrity and appeared metabolically active. The secondary phase was degradative in nature. Ultrastructural changes observed during this phase were representative of those that occur in a virus‐induced incompatible or hypersensitive (necrotic) reaction. Such changes included rounding of chloroplasts, vesiculation and disintegration of the plasma membrane and tonoplast, degeneration of cell organelles, and generalized plasmolysis. Subsequently, the cell walls collapsed, developing folds and loops around the shrunken cytosol. The collective result of these two ultrastructurally distinctive phases was the production of large necrotic lesions in the inoculated leaf, but no systemic viral spread.
The Effect of Environmental Conditions on the Expression of Disease in Cultured Tissues of Brassica napus ssp. oldfera Infected with Leptosphaeria maculans
Authors: Gretenkort Marie A. , Ingram D. S. 
Published: May 2008

AbstractAs a basis for devising an in vitro screening programme, culture conditions were optimized so that tissue cultures from two resistant cultivars of Brassica napus ssp. oleifera (Mikado, Bienvenu) and two susceptible cultivars (Lesira, Ceres) could be differentiated using a disease scoring scheme, when inoculated with Leptosphaeria maculans. Tissues inoculated included thin cell layer explants from soil‐grown plants and in vitro‐grown shoot cultures and callus tissue formed on such explants. The period of incubation and the incubation temperature were of importance in the development of differential disease reactions. Increasing temperature generally resulted in an increase in infection and too great an incubation period resulted in total overgrowth of the tissue. Increasing concentrations (1 × 10−6 M‐1 ×10−4 M) of the auxins 1‐naphthylacetic acid (NAA), 2,4‐dichlorophenoxyacetic acid (2,4‐D) and mdole‐3‐acetic acid (IAA) in the culture medium, resulted in a decrease in disease score of the thin cell layer (TCL) explants from soil‐grown plants. The cytokinins examined 6‐benzyl‐aminopurine (BAP) and 6‐4‐hydroxy‐3‐methyl‐2‐enylaminopurine (zeatin), reduced the extent of infection of the TCL explants when used in combination with the auxin NAA. Medium containing NAA at a concentration of 1 × 10−6 M in combination with BAP at a concentration of 1× 10−6 or 1 × 10−4 M allowed differentiation of the disease reactions of the resistant and susceptible cultivars, when the explants were incubated for 10 days at 20 °C after inoculation. Similar conditions of incubation and the addition of NAA (1 × 10−6 M) combined with BAP (1 × 10−6 M) to the medium also allowed the differentiation of the disease reactions on TCL explants from stems of in vitro shoot cultures of the cultivars Mikado and Lesira. Increasing concentrations of the auxin NAA and the cytokinin BAP resulted in a reduction in the mean disease score of the callus tissue produced on TCL explants from soil‐grown plants, and NAA (1 × 10−5 M) combined with BAP (1 × 10−6 or 1 × 10−5 M) allowed differentiation of resistance and susceptibility in callus tissues when incubated for 5 days at 20 °C. 2,4‐D did not allow differentiation of the cultivars. This was in contrast to the inoculation of callus tissue attached to TCL explants of in vitro shoot cultures, where combinations of 2,4‐D and BAP at concentrations of 1 × 10−6 M allowed differentiation of the resistant and susceptible cultivars.These findings provide a basis for designing selection protocols of value in both traditional as well as in vitro breeding programmes to select lines of oilseed rape with resistance/novel resistance to L. maculans.
Severe Erwinia‐Caused Damage on Opuntia ficus‐indica in Italy
Authors: Varvaro L. , Granata G. , Balestra G. M. 
Published: May 2008

Abstract Erwinia carotovora subsp. carotovora. was consistently isolated from diseased tissues of prickly pear cactus (Opuntia ficus‐indica) in Sicily. The bacterium was identified on the basis of morphological, cultural, biochemical and physiological characters as well as on the basis of pathogenicity. Symptoms were observed on cladophylls and fruit: watersoaked spots became brown and coalesced; the external tissue became dry and frequently cracked; the internal tissue turned brown to almost black. The disease was first localized in a few plantations, then seriously spread to all the modern intensive cultivations of prickly pear cacti.
Resistance of Sclerotinia minor Isolates to Cyclic Imides in Lettuce Field Soils of Roussillon, France
Authors: Davet P. , Martin C. 
Published: May 2008

AbstractLettuce drop caused by Sclerotinia minor Jagger is the most common disease affecting lettuce crops during the fall and winter in Roussillon. Spraying of cyclic imide fungicides (iprodione, vinclozolin, and less commonly procymidone) generally provides satisfactory protection. However, since about 1985, the mean field efficacy of iprodione and vinclozolin has significantly decreased, whereas that of procymidone is currently not in question. The appearance of fungicide‐resistant isolates of S.minor could explain the reduced efficacy of these fungicides. We thus looked for iprodione and procymidone‐resistant isolates of S.minor in these problem fields. The investigations were earned on for over 3 years. Most of the isolates showed fungicide sensitivity (iprodione IC 50 = 0.17 mg 1−1), about one quarter showed average resistance (iprodione IC 50 = 0.59 mg 1−1) and a few were found to be highly resistant. Resistant isolates were also obtained in vitro when using high fungicide concentrations. Moreover, isolates resistant to iprodione were found to be resistant to procymidone. The most highly resistant isolates produced fewer and larger‐sized sclerotia than the sensitive isolates, they were also more quickly inhibited by high osmotic pressures. Field variability was quite low: 73 of 74 isolates obtained from one field were found to be sensitive, with only one showing mild resistance. There did not seem to be any correlation between the observed decrease in the field efficacy of iprodione and the presence of resistant isolates.
Compatible and Incompatible Interactions Between Callus Tissue and Mycorrhizal or Pathogenic Fungi
Authors: Sbrana Cristiana , Giovannetti Manuela , Buiatti Marcello , Storti Emanuela 
Published: May 2008

AbstractTissue cultures of Nicotiana tabacum were utilized to investigate the mechanisms associated with host specificity and non‐host incompatibility in mycorrhizal and pathogenic fungi. They were tested for expression of resistance to different species of mycorrhizal fungi and to a fungal pathogen of tobacco, Thielaviopsis basicola, by monitoring the production of callose, phenolic compounds and peroxidases in dual cultures. Tobacco cells reacted to the presence of all the mycorrhizal fungi with callose deposits, whereas callose was nearly always absent in tobacco cells inoculated with their pathogen T. basicola. The broad‐host range ectomycorrhizal fungi Hebeloma crustuliniforme, Lac‐caria laccata and Suilhis granulatus elicited less intense responses than did Hymenoscyphus ericae. The results obtained for phenolic production and peroxidase activity were consistently similar to those obtained for callose deposition. They showed that H. ericae, an endomycorrhizal symbiont of Ericaceae, was highly incompatible with tobacco cells and that the tobacco pathogen T. basicola did not elicit strong reactions in the cells of its host. In this paper, the possibility of utilizing callus cultures as a simple model system to study both the different degrees of compatibility and the early events of recognition between mycorrhizal fungi and their host or non‐host plants is discussed.
Effect of UV‐C on Phytoalexin Accumulation and Resistance to Botrytis cinerea in Stored Carrots
Authors: Mercier Julien , Arul Joseph , Julien Chantal 
Published: May 2008

AbstractThe effect of UV‐C (220–280 nm) on the accumulation of phytoalexin and resistance to Botrytis cinerea was studied in cold‐stored carrots. Carrots were surface‐wounded, treated with a range of UV doses and stored at 1 °C for 25 days in lots of 22 roots. The level of the phytoalexin, 6‐methoxymellein, in each lot was then assayed in the peel of eight roots. Twelve of the remaining roots were subsequently inoculated with mycelial plugs to evaluate their level of disease resistance. The elicitation of 6‐methoxymellcin by UV increased significantly the resistance of the roots to B. cinerea. The effect of UV in freshly harvested carrots was curvilinear, showing an optimum between 0.44 and 0.88 Merg/cm2. However, only a linear relationship was observed with aged (stored for 4 months at 1 °C) carrots for the same doses, suggesting a modification in the response to UV with age. Wounding was necessary for carrots kept at 1 °C to respond to UV treatment. Neither UV nor wounding alone caused any elicitation at this temperature. Since unwounded roots could respond to UV at 20 °C, it is hypothesized that the level of physiological activity of the roots determines their response to UV. An increase in the physiological activity by higher temperatures or wounding would allow the elicitation process to take place. Since UV irradiation can increase the level of disease resistance in treated tissues, this treatment has potential as an alternative method for the control of post‐harvest diseases m carrots.
A Comparison of Screening Techniques for Resistance to Verticillium Wilt in Alfalfa (Medicago sativa L.)
Authors: Yu Kang‐Fu , Christie B. R. , Pauls K. P. 
Published: May 2008

AbstractThree screening tests for resistance to Verticillium wilt in alfalfa using stem cuttings were compared including: stem infusion with a fungal culture filtrate (SIF), leaf injection with a spore inoculum (LII) and stem infusion with a spore inoculum (SII). The disease severity indice (DSI) determined by the three tests were very similar on average and were significantly correlated for a population of 142 plants regenerated from tissue culture. The DSIs determined by the LII test were also significantly correlated with the DSIs determined by the North American Standard test in a population of 20 Vertus (c.v.) plants. The results suggest that the assays using stem cuttings are effective for determining resistance to Verticillium wilt in alfalfa. Because they are nondestructive and quicker than the North American Standard test, these methods should find application in alfalfa breeding.