bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation Between Induced Resistance and Host Fluorescence in Barley Inoculated with Erysiphe graminis
Authors: Thordal‐Christensen H. , Smedegaard‐Petersen V. 
Published: May 2008

AbstractResistance was induced in barley by virulent and avirulent Erysiphe graminis f. sp. hordei and by E. graminis f. sp. tritici. The diameters of fluorescent haloes and papillae at the site of the primary germ tube of the inducers were larger until 12 hours after inoculation with E g. f. sp. tritici than in the corresponding periods after inoculation with E. g. f. sp. hordei. Fluorescence at the site of appressorial lobes of the inducers developed, gradually from 10 and 12 hours after inoculation with E. g. f. sp. hordei and E. g. f. sp. tritici, respectively. Penetration success of single infection units of the challenger was reduced in cells with inducer fluorescence, suggesting that resistance is principally localized to cells previously attacked by the inducer. But penetration success was independent of the average distance to the ten nearest inducer fluorescences, and penetration failures did also occur in cells without inducer fluorescence, suggesting that the induced resistance to some extent is translocated to other epidermal cells. The average diameter of the fluorescent papillae at the site of unsuccessful challenger infection units increased as a result of induced resistance.
Effect of Foliar Applications of Fungicides on the Phylloplane Mycoflora and Fungal Pathogens of Guava
Authors: Pandey R. R. 
Published: May 2008

Abstract Colletotrichum gloeosporioides and Pestalotia psidii were found to be the dominant pathogens causing leaf spots and fruit diseases of guava. Effects of two fungicides in rainy (wet) and four fungicides in the winter (dry and cool) seasons separately, in concentrations of 500, 1500 and 3000 mg a.i. I−1 (ppm) have been investigated on the pathogens and on composite phylloplane fungi. Benomyl was found most effective against the population of pathogens and checked disease development. However, it was effective only at the schedule of three successive foliar applications. The application of captan did not check P. psidii as effectively as benomyl but it had a marked adverse effect on many of the phylloplane fungi. A signif, icant decrease in the number of fungal species colonizing mancozeb and dichlone‐treated leaves was observed. Lesion measurement and spore germination tests against both pathogens following chemical treatments in vivo and in vitro respectively have also been made.
Pathogenicity of Geographic Isolates of Fusarium oxysporum from Crucifers on a Differential Set of Crucifer Seedlings
Authors: Bosland P. W. , Williams P. H. 
Published: May 2008

AbstractPathogenicity tests with 103 isolates of Fusarium oxysporum from crucifers worldwide were conducted using a standard set of six differential crucifer cultivars. Based on their reaction to the standard differentials, all isolates could be grouped into the five major pathotypes in the three formae speciales, f. sp. conglutinans. f. sp. raphani and f. sp. matthioli. When two additional crucifers, Brassica nigra and B. campestris were added to the differe, ntial set, and the reactions of the host differentials were analyzed, an increased range of virulence profiles was observed, implying the existence of more virulence factors in the F. oxysporum population. An isolate from the U.S.S.R., was identified with virulence capable of overcoming dominant monogenic “type A” resistance in Brassica oleracea suggestive of a potentially new location for this pathotype.
Isolation of a Plasmid from Xanthomonas campestris pv. vignicola
Authors: Ulaganathan K. , Mahadevan A. 
Published: May 2008

AbstractA modified method is described for isolating high yields of plasmids without chromosome contamination from Xanthomonas campestris pv. vignicola (X. c. pv. vignicola), the causal agent of blight disease in Vigna species and also in Phaseolus vulgaris. Applying this method a plasmid of X, c. pv. vignicola was detected representing an estimated molecular weight of 95 megadaltons. Heat curing of the strain revealed that the detected plasmid had no effecton virulence but seemed to influence colony morphology.
Systemic Acquired Resistance Induced in Tobacco Plants by Localized Virus Infection Does Not Operate Against Challenging Viruses That Infect Systemically
Authors: Pennazio S. , Roggero P. 
Published: May 2008

AbstractLocalized infections produced by tobacco necrosis virus (TNV) or tomato mosaic virus (ToMV) in White Burley tobacco induced a systemic acquired resistance in upper, uninoculated leaves. This resistance was effective against challenge infection by TNV or ToMV but not by potato virus Y, necrotic strain (PVYn), tobacco mosaic virus (TMV) or tobacco rattle virus (TRV), viruses giving systemic infections.Systemic acquired resistance against TNV or ToMV was expressed as a reduction in lesion size but not in viral antigen content of the resulting necrotic local lesions. The acquisition of resistance was concurrent with an increased capacity of the resistant leaves to convert 1‐aminocyclopropane‐1‐carboxylic acid into ethylene.Systemic acquired resistance was ineffective to contrast or minimize in whatever way the systemic challenge infection produced by PVYN, TMV or TRV. Severity of symptoms and virus multiplication did not differ in resistant leaves from controls. This result does not allow any optimistic promise on possible application of the systemic acquired resistance against severe viral diseases of crops.
Involvement of Epicatechin in Cultivar Susceptibility of Avocado Fruits to Colletotrichum gloeosporioides after Harvest1
Authors: Prusky D. , Kobiler I. , Jacoby B. 
Published: May 2008

AbstractAvocado cultivars were defined as susceptible and resistant to Colletotrichum gloeosporioides depending upon the length of the incubation period of the disease after fruit softening. In the susceptible cultivars Fuerte, Horshim, Vurtz, Rincon, and Benik, epicatechin concentration of the peel decreased to 60‐130 μg.g−1, fr. wt. at fruit softening and symptoms appeared on the same or one day later. In the resistant cultivars Hass, Nabal, Netaim and Pinkerton, epicatechin concentration was still 632–1740 μg.g−1 fr. wt. when fruit softening and symptoms appeared only 4‐10 days later. When susceptible Fuerte fruits became soft the concentration of the antifungal compound 1‐acetoxy‐2‐hydroxy‐4‐oxo‐heneicosa‐12,15 diene, had decreased to 120 μg.g−1 fr. wt. and symptoms appeared. In resistant Hass fruits, the antifungal diene was still 238 μg.g−1 fr. wt. at fruit softening; and it had further decreased to 159 μg.g−1 fr. wt. when symptoms appeared, four days later. A modified atmosphere and 0.2 M CaCl2 infiltration both delayed softening of Fuerte fruits; but symptom appearance on these fruits was related to diene decrease and not to fruit softening.The results are discussed in relation to the hypothesis that the susceptibility of avocado cultivars to post‐harvest decay by C. gloeosporioides is related to the degradation of the antifungal diene, catalyzed by avocado lipoxygenase, the activity of which is regulated by the decline of its inhibitor epicatechin.
Further Studies on Cynara Rhabdovirus
Authors: Rana G. L. , Franco A. di , Galasso I. 
Published: May 2008

AbstractCynara rhabdovirus (CyRV) was isolated from symptomless artichoke plants in southern Italy using Nicotiana langsdorffii as susceptible host and immune serum to artichoke latent virus to eliminate this virus from inoculum. CyRV can infect several solanaceous species, has thermal inactivation point of 40‐45°C, dilution end point between 10−2 and 10−5 and longevity in vitro at 4 and 20°C of 4‐5 days and 6‐24 h, respectively. It was purified and used for preparing antisera with homologous titre varying from 1: 16 to 1: 64. In decoration tests, the virus did not react against antisera to eggplant mottled dwarf virus (EMDV) and its antiserum did not decorate ivy vein clearing virus (IVCV). Ultrastructural aspects of CyRV infection in Datura stramonium and Nicotiana glutinosa were very like those described for the same virus in the past except for presence of longer virions which were often encountered in infected cells during this study.
Effect of Wheat Streak Mosaic Virus Infection on Total DNA and Chloroplast Ribosomal RNA in Wheat Leaves
Authors: Brakke Myron K. , White J. L. , Samson R. G. , Joshi J. 
Published: May 2008

AbstractThe amount of chloroplast 23s rRNA relative to either DNA or to cytoplasmic 28s rRNA was reduced in young wheat leaves infected with wheat streak mosaic virus.Chlorophyll was reduced in infected leaves. Fresh weight per leaf and DNA content per leaf were reduced in infected leaves, but DNA per g was increased.Cytoplasmic ribosomal RNA appeared to degrade more slowly during senescence in infected leaves than in uninfected. Virus was undetectable by density gradient centrifugation in systemically infected leaves less than 6 cm long and reached its highest concentration when young leaves reached their maximum size. Mosaic developed in leaves that became infected when 5 cm long or less. Since the entire leaf eventually developed mosaic, the events leading to mosaic occur after cell division, which is limited, to the basal cm of young leaves.
Induction of Pathogenesis‐related Proteins in Barley during the Resistance Reaction to Mildew
Authors: Bryngelsson T. , Gustafsson M. , Leal M. Ramos , Bartonek E. 
Published: May 2008

AbstractChanges in the soluble protein pattern of leaves of eight lines of barley, carrying different resistance genes to mildew, were analysed by SDS‐polyacrylamide gel electrophoresis and isoelectric focusing. Apparently new host proteins were induced by Erysiphe graminis f. sp. hordei in the incompatible reaction which were not present in the immune or susceptible response. These proteins are of low molecular weight, 13,500–27,500 d, and have either very low or very high isoelectric points. Thus, they resemble the pathogenesis‐related proteins found in many dicotyledonous species.
Resistance to Leptosphaeria maculans in Hybrids of Brassica oleracea and Brassica insularis
Authors: Mithen R. F. , Lewis B. G. 
Published: May 2008

AbstractThe inheritance of hypersensitive resistance to Leptosphaeria maculans in a cross between B. oleracea var. alboglabra and B. insularis was studied. Analyses of F1 and F2 progeny suggested that resistance is determined by two dominant, independently‐segregating genes. F1 hybrids were semifertile but normal levels of fertility were restored in a proportion of the F2 progeny.
Phyllody Disease of Crotalaria saltiana in the Sudan: Transmission to Catharanthus roseus and Detection of MLOs by Fluorescence and Electron Microscopy
Authors: Dafalla G. A. , Cousin M. T. 
Published: May 2008

AbstractPhyllody disease of Crotalaria saltiana Andr. first noted in the Sudan in 1962, was recently observed in many localities in the Gezira province in the central region of the country. Diseased plants generally exhibited stunting and excessive proliteration of lateral shoots (witches' broom growth) with small and chlorotic leaves. Morphological transformations of flowers were the most striking symptoms. Floral segments showed various stages of virescence and phyllody as a part of a complete transformation of floral buds into leafy branches. The Crotalaria phyllody agent was transmitted by grafting to faba bean (Vicia faba L.) and with dodder from the latter to periwinkle (Catharanthus roseus). The symptoms reproduced in C. roseus resembled those induced in it by the faba bean phyllody MLO (mycoplasma‐like organism), suggesting a close relationship between the two agents. Fluorescence and electron microscopy were used to detect and characterize MLO in diseased plants. Fluorescence reactions in sieve tube elements were observed in sections stained with the DNA‐binding fluorochrome Bisbenzimid H 33258. Electron microscope observations in corresponding zones permitted the visualization of wall‐less pleiomorphic MLOs confined to sieve tube elements of the phloem tissues of diseased plants.
Pathogenicity of Race‐1 and Race‐2 Tomato Wilt Isolates of Verticillium dahliae from Different Geographical Origins
Authors: O'Garro L. W. , Clarkson J. M. 
Published: May 2008

AbstractFourteen race‐1 and race‐2 isolates of Verticillium dahliae from North America, Europe and Australia were screened against the near isogenic pair of tomato cultivars Roma and Roma VF. The foliar symptoms, extent of stunting and vascular colonization were assessed. Race‐1 isolates were significantly more pathogenic on Roma which lacks the Ve resistance gene. Race‐2 isolates from N. America were more pathogenic than those from Australia. All isolates tested colonized both cultivars to some extent although the level of colonization by race‐1 isolates was significantly higher in Roma than in Roma VF. All race‐1, and the majority of race‐2, isolates caused stunting of Roma. No isolates stunted Roma VF.
Dependence of the Effectiveness of Induced Resistance on Environmental Conditions
Authors: Falkhof A.‐G. , Dehne H.‐W. , Schönbeck F. 
Published: May 2008

AbstractResistance induced by microbial metabolites against powdery mildew on barley always proved to be highly effective particularly under practical conditions in field. The results obtained in the present study demonstrate that the successful induction of resistance requires a conditioning of plants by the environmental conditions acting prior to the application of the inducer. If plants were grown in the greenhouse or outdoors, the infection densities were efficiently reduced after the treatment with the inducer. In contrast to this the disease intensities were not reduced on plants grown at constant temperature, light and humidity conditions. Frequently changing temperatures and the daily courses of temperature, normally occurring in greenhouse or outdoors, were substantiated as the most important factors for a successful induction of resistance. The conditioning of the plants under these temperature conditions depended on light energy, especially in just developing leaves. The dependence of the induced resistance on the environmental conditions was proved with other host‐pathogen‐relationships as well as with barley and powdery mildew.
Characterization of Isolates of Bacterial Blight of Cotton (Xanthomonas campestris pv. malvacearum) from Nicaragua
Authors: Zachowski A. , Rudolph K. 
Published: May 2008

AbstractSeeds from cotton plants infected with Xanthomonas campestris pv. malvacearum were collected in different parts of Nicaragua in 1986. When the seeds were homogenized the pathogen could not always be identified by dilution plating. Therefore, an enrichment of bacteria on the natural host was induced before isolation. The cotton seeds were shaken with water and sand for 2 days and then sown in sand for germination. Rather often the developing cotyledons showed typical water‐soaked spots, from which the pathogen could be isolated easily. This new method needed more time but made it possible to detect a low level of bacterial infestation. Altogether, 42 bacterial isolates were obtained.For inoculation experiments suspensions with 5x105 CFU ‐ ml−1 were infiltrated into cotton leaves. Incubations of inoculated plants in growth chambers, but not in greenhouses, resulted in typical and uniform disease symptoms (water‐soaked leaf spots). Nine of the ten cotton differentials tested were highly susceptible to all the 42 bacterial isolates. Since only line 101‐102B proved to be resistant, the Nicaraguan isolates of bacterial blight of cotton were characterized as race 18, of the pathogen. The main cotton cultivars grown in Nicaragua (H‐373 and G‐286) were strongly affected by the isolated bacterial strains. In order to reduce the disease incidence in Nicaragua, the cultivation of resistant cotton varieties is suggested.
Stimulation of Fruit Ethylene Production by Wounding and by Botrytis cinerea and Geotrichum candidum Infection in Normal and Non‐Ripening Tomatoes
Authors: Barkai‐Golan Rivka , Lavy‐Meir Gila , Kopeliovitch E. 
Published: May 2008

AbstractInoculations with both Botrytis cinerea and Geotrichum candidum stimulated ethylene evolution in the pre‐climacteric normal tomato fruit and the non‐ripening nor mutant which did not show any rise in ethylene when uninfected. In the post‐climacteric normal fruits, new peaks in ethylene production were formed. The rise in ethylene evolution in all types of infected fruits has already been detected during the incubation period of the disease. Ethylene peaks were detected earlier and were higher in fruits infected with B. cinerea than with G. candidum, coinciding with the faster rate of growth of the former. Mechanical wounding also stimulated ethylene synthesis by the non‐ripening fruits, production being directly proportional to wound dimension. Considerably higher rates of ethylene were recorded for infected fruits than for mechanically‐injured fruits in which wound dimensions were similar to those of lesion development.Applying aminoxyacetic acid at the site of inoculation inhibited ethylene production by 55–60 % in the normal fruits and by about 80 % in the nor mutant fruits. A similar pathway of ethylene synthesis was suggested for normally ripening tomato fruit and non‐ripening infected tissues.
Transmission of a New Mycoplasma‐Like Organism (MLO) from Cuscuta odorata (Ruiz et Pav.) to Herbaceous Plants and Attempts to its Elimination in the Vector
Authors: Heintz W. 
Published: May 2008

AbstractA new MLO‐type, originating from a holoparasite plant Cuscuta odorata (Ruiz et Pav.) causing stunting and reduction of flower‐ and leaf size on Catharanthus roseus (L.) G. Don. (HEINTZ 1986) was transmitted to Apium graveolens L., Plantago major L., Bellis perennis L. and Cirsium japonicum hybrid. The observed symptoms on the test plants probably caused by the MLO have not yet been described in the literature. The symptomatology on these herbaceous plants gives further data in order to classify the MLO as a new one which is named Guscuta latent MLO (Cl‐MLO). Attempts to transmit the pathogens by the leafboppers Euscelidius variegates (Kirschbaum) and Euscelis lineolatus (Brullé) failed. It also was impossible to elimmate the MLO completely from Cuscuta odorata by heat treatment and antibiotic application. However, we succeeded in eliminating the pathogens from Catharanthus roseus by heat treatment.
Occurrence in Soil and Primary Infections of Pseudomonas corrugata Roberts and Scarlett
Authors: Scortichini Marco 
Published: May 2008

AbstractThe occurrence of Pseudomonas corrugata in soil has been checked. Semiselective medium TNR (a modified SNR) permitted to isolate the causal agent of “tomato pith necrosis” from that source. The average soil population of the bacteria was 3.1 × 104 CFU × g of soil. P. corrugata was also isolated from plants sowed in the naturally infected soil. It was supposed that primary infections came from here.
Direct Introduction of Fluorescein Isothiocyanate‐conjugated Albumin into Intact Macroconidia of Fusarium oxysporum f. sp. lycopersici by Electroporation
Authors: Matsuda Y. , Toyoda H. , Nishiguchi T. , Ouchi S. 
Published: May 2008

AbstractAn electroporation procedure for the introduction of fluorescein isothiocyanate‐conjugated albumin into intact macroconidia of Fusarium oxysporum f. sp. lycopersici was performed in this paper. FITC‐albumin was used to establish an efficient electroporation procedure because its presence in spores could be easily detected by fluorescence microscopy. The uptake of fluorescein isothiocyanate‐conjugated albumin into spores was successfully mediated by high voltage electrical pulses at field strength of 10 KV/cm. In electroporation of 106 macroconidia per ml with the present system, 1.2 × 105 spores incorporated the protein, and then 3.1 × 104 normally germinated, elongated vegetative hyphae, and produced spores.
Roditis Leaf Discoloration ‐ A New Virus Disease of Grapevine: Symptomatology and Transmission to Indicator Plants
Authors: Rumbos I. C. , Avgelis A. D. 
Published: May 2008

AbstractThe symptoms and some characteristics of an unreported disease of grapevine, which was observed during the last years on the cv. ‘Roditis’ in central Greece, are described. The disease is transmissible to V. vinifera‘Mission’ and to some herbaceous test plants. The constant association of a virus to naturally infected plants cv. ‘Roditis’ and chip‐budding infected indicator plants cv. ‘Mission’ supports the evidence that the disease is caused by a virus.
Epidemics of Diseases and Pests of Winter Wheat at Different Levels of Agrochemical Input
Authors: Daamen R. A. , Wijnands F. G. , Vliet G. vander 
Published: May 2008

AbstractThe cropping system with winter wheat has changed considerably during the past fifteen years in the Netherlands. Crop biomass has been increased by use of new cultivars and higher levels of fertilizers and pesticides. The question which arises is to what extend the level of fertilization affects epidemics of pests and diseases, compared to the well‐known effects of pesticides and cultivars. Epidemics observed in the winter wheat fields of the Development Farming System project (DFS) at Nagele, in 1984 and 1985 provided data for this analysis. Higher levels of fertilization stimulated epidemics of yellow rust, mildew, snow mould, leaf miners and cereal leaf beetles in the fields. The magnitude of the effect was comparable to those of the pesticides used and the cultivars sown. The level of fertilization showed no effect on five other species. How these interrelations between cropping practices and the associated development of pests and diseases can be used to design an integrated approach towards cereal cropping and breeding is discussed.
Dracaena Leaf Proliferosis, a Newly Recorded Disease Affecting Dracaena sanderiana in Egypt
Authors: Wagih E. E. , Shehata M. R. A. , Farag Samia A. , Dawood M. K. 
Published: May 2008

AbstractDracaena leaf proliferosis is a newly reported disease affecting Dracaena sanderiana in Egypt. A cause and effect relationship between this disease and the fungus,Fusarium proliferatum var. minus has been established. In addition to D. sanderiana the fungus was found to be pathogenic, when tested in the laboratory, to several other members of the family Liliaceae. While the in vitro growth of the fungus is optimum at 25 °C, symptom expression is best at 30°C. Twelve fungicides were tested for their in vitro effect on fungal growth. Benlate, Rubigan, Saprol, Cercobin and Vitavax‐200 came first on the list and inhibited growth at 2.5, 12.0, 55.0, 75.0, and 94.0 μg/ml, respectively. Although, Benlate was the most effective fungicide in this respect it failed to demonstrate similar effect on disease development when applied to plants artificially inoculated with the fungus. Fungal growth was completely inhibited on PDA medium by a bacterium belonging to Bacillus sp. but when the bacterium at a concentration of 1 × 1011 cell/ml was applied 24 h before, at the same time with, or 24 h after inoculation no control of the disease was achieved. Naturally‐infected plants could, however, be freed from infection when subjected to a hot air treatment at 35 ± 5 °C during day time and 25 ± 5° C at night for 3 months.