bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro Analysis of Defence Mechanism in the System Solanum tuberosum‐Alternaria alternata
Authors: Pellegrini M. G. , Garbuglia A. R. , Guerrazzi S. , Bogani P. , Bettini P. , Storti E. , Simeti C. , Buiatti M. , Broggio M. , Nascari G. 
Published: May 2008

AbstractIn a preliminary study on the interaction between an Alternaria alternata pathotype and Solanum tuberosum a series of parameters, indicative of active and passive defence processes, was investigated in vitro using tolerant (Chiquita) and susceptible (Superior) cultivars. Ion leakage experiments along with growth of suspension cultures and plating efficiencies in the presence of fungal culture filtrates suggest that toxin tolerance is a valuable character in distinguishing between resistant and susceptible genotypes. As far as active defence was concerned, although TLC patterns suggested the synthesis of different fluorescent compounds, probably phenolic acid, when fungal elicitors were applied to Chiquita or susceptible tissue,cultures, no consistent pattern suggesting a relationship with defence could be observed. On the other hand, peroxidase isozyme analysis after different dual culture periods showed the activation of ionically and covalently bound peroxidases in the prese,nce of the pathogen only in cv. Chiquita.
An Inflorescence Disease of Amaranthus spp. in Nigeria Associated with Choanephora cucurbitarum
Authors: Adebanjo A. 
Published: May 2008

Abstract Symptoms of a devastating inflorescence disease of Amaranthus spp. associated with Choanephora cucurbitarum are described. It is characterized by extensive blighting of the inflorescence head and is often accompanied by inflorescence dieback and severe breaking of the floral head. In fields with severe infestation and under favourable conditions the inflorescence heads may be completely cut off. Such a plant will not produce any seeds or the yield may be reduced to half or less.Laboratory experiments confirm observations made in the field that the fungus is aggressively pathogenic on the apical region of the inflorescence. Usually, the green young inflorescences are more susceptible.
Occurrence of Eggplant Mottled Dwarf Virus in Jordan
Authors: Al‐Musa A. M. , Lockhart B. 
Published: May 2008

Abstract A virus isolated from stunted eggplant (Solanum melanogena L.) with severe vein yellowing, was identified as a strain of eggplant mottled dwarf rhabdovirus (EMDV‐J) on the basis of host range, transmissibility and serology.The isolate is seemingly a unique strain of eggplant mottled dwarf virus that differs from the reported strains in the host range.The virus was recovered from Withania somnifera, a perennial plant, which suggests the availability of a virus reservoir at times when the Jordan valley is practically free from cultivated eggplants.
Beziehungen zwischen dem Wirkungsgrad antiphytoviraler Substanzen und dem Niveau der quantitativen Sortenresistenz sowie der Virulenz von Virusisolaten an Virus/Wirt‐Systemen der Kartoffel
Authors: Bittner Heide , Schenk G. 
Published: May 2008

Abstract Relationship between the efficiency of antiphytoviral substances, the degree of quantitative resistance of cultivars, and the virulence of virus isolates on virus/host‐systems of potato. In vitro systematically infected with potato virus S, potato virus M or potato virus X stem cuttings of different potato varieties were treated with 2,4‐dioxohexahydro‐1,3,5‐triazine and Ribavirin. The reduction of virus replication by chemotherapy differed between varieties depending on their level of quantitative resistance and the virulence of virus isolates.An increasing resistance level of cultivars and a decreasing virulence of the virus isolates resulted in a relative enhancement of the inhibitory of the antiphytoviral substances.
Effect of Some Factors on Detectability of Virulence Genes in Phytophthora infestans (Mont.) de Bary
Authors: Sujkowski LudwikS. 
Published: May 2008

Abstract Inoculum concentration, length of incubation period and passages on leaves of potato R–genotypes were found to influence the detectability of virulence genes in Phytophthora infestans.At lower inoculum concentrations, only a few virulence genes were detected, these were usually 1 and 4. Coupled with an increase of the inoculum dose a gradual increase was found in the number of detected genes and their multiple combinations. An increased incubation time also resulted in the detection of additional virulence genes and their combinations. Two successive passages on respective potato R‐genotypes produced a 2‐‐3 fold rise in the number of detected genes.To explain this phenomenon, a hypothesis has been proposed which suggests that for a virulence gene to be detected, certain infection thresholds have to be reached, which may be different for particular differential host genotypes or virulence genes.
Histology of Disease Development in Resistant and Susceptible Cultivars of Chickpea (Cicer arietinum L.) Inoculated with Spores of Ascochyta rabiei
Authors: Höhl B. , Pfautsch M. , Barz W. 
Published: May 2008

Abstract Histological studies were performed on a compatible and an incompatible interaction between chickpea (Cicer arietinum L.) plants and the fungus Ascochyta rabiei (Pass.) Labr. The time course of infection, development on leaflets and stems of susceptible (ILC 1929) and resistant (ILC 3279) plants was monitored by light or scanning electron microscopy with the aim to compare histological changes as the basis for further work on biochemical changes in this plant‐pathogen interaction.Spores of A. rabiei began to germinate from 12 hpi on and developed a polar germ tube; fungal colonization, secretion of a mucilaginous exudate and appressoria formation (1–3 dpi) were identical on both cultivars. Leaves of susceptible plants were invaded by the fungus directly through the cuticle, the fungus then spread subepidermally followed by a rapid collapse of the leaf tissue (4–6 dpi). Development of leaf spots and fungal pycnidia could be observed 6–8 dpi. The resistant cultivarrapidly responded (24–48 hpi) to fungal infection and cells of the palisade parenchyma exhibited autofluorescence. In later stages of the infection (4–5 dpi) fluorescent areas developed to small necrotic spots all over the leaflet. These necrotic areas, were the result of cell death and a subsequent change in the leaf structure and were characterized by the accumulation of phenolic compounds. Leaves of the resistant cultivar were invaded by the fungus to less than 5%.
Some Etiological Characteristics of Xanthomonas campestris pv. sesami and Disease Reaction of Different Sesame Cultivars
Authors: Abdel‐Rahim A. M. , Adam F. S. 
Published: May 2008

Abstract Isolates of X. campestris pv. sesami used in the present work behaved almost similarly on the basis of their morphological, biochemical and physiological characterization. The studies failed to differentiate any strains within the isolates.Pathogenicity of the isolates to sesame plants was proved by inoculation experiments. When other plant species were inoculated infection did not occur.The levels of resistance of some naturally selected sesame cultivars were investigated following artificial infection with the pathogen. Seven cultivars proved resistant, three (cvs Tozi 3, S‐76F2‐22 and K 112) were highly resistant.
Comparison of Polyclonal Antisera in the Detection of Tomato Spotted Wilt Virus Using the Double Antibody Sandwich and Cocktail ELISA
Authors: Resende R.deO. , Avila A. C.de , Goldbach R. W. , Peters D. 
Published: May 2008

AbstractDifferent polyclonal antisera and enzyme‐linked immunosorbent assay (ELISA) procedures have been tested for their potential to detect tomato spotted wilt virus (TSWV). The virus could efficiently be detected in high dilutions of sap from infected plants, and at low concentrations of purified virus and nucleocapsid protein preparations in the cocktail ELISA and the double antibody sandwich ELISA (DAS‐ELISA). Amounts of 1 to 3 ng of virus protein still gave positive readings using purified preparations, while sap could be diluted approximately 100,000 times. Differences in the detection level were observed using nucleocapsid protein antiserum (anti‐N‐serum) and the antiserum against intact virus particles (anti‐TSWV‐serum), but both antisera showed to be powerful sera for the detection of TSWV. Using anti‐N‐serum, TSWV could be detected in highly diluted extracts of different hosts, and also in leaf extracts or intact tissues stored for 30 days under different conditions. These results indicate that the TSWV nucleocapsid protein remains antigenic for long periods.
Cellular Damage to Phytophthora infestans in Tomato Leaves Treated with Oxadixyl: an Ultrastructural Investigation
Authors: Jiang Yong , Grossmann F. 
Published: May 2008

AbstractUltrastructural observations showed massive accumulation of electron dense deposits adjacent to plasmalemma and mitochondria and mitochondrial degeneration, which probably leads to cell death, in some hyphae and haustoria of Phytophthora infestans in infected tomato leaves treated with the systemic fungicide oxadixyl (8 μg/ml). However, no changes in the endoplasmic reticulum and number of ribosomes were observed. The cell walls of some hyphae were markedly thickened after oxadixyl treatment. Degenerated haustoria were partly present in intact host cells. Evidently, fungal cell damage by treatment with oxadixyl is not correlated with host cell damage.
Neither Indole Acetic Acid nor Bacteriocin is Apparently Involved in the in vitro Antagonism between the Virulent and the Avirulent Strains of Pseudomonas solanacearum
Authors: Wagih ElsayedE. 
Published: May 2008

AbstractAn avirulent strain of Pseudomonas solanacearum could inhibit the growth of its virulent parent on L‐tryptophan‐containing glycerol nutrient agar (TGNA) medium. It was, also, capable of inhibiting, though to a less degree, Corynebacterium fascians and Pseudomonas marginata, out of five other bacterial species tested. While P. marginata was partially inhibited by the avirulent strain it was totally insensitive to indole‐3‐acetic acid (IAA) up to a concentration of 300 μg/ml. Additionally, Erwinia carotovora var. atroseptica which was totally unaffected by the avirulent strain showed a spectrum of sensitivity to IAA concentrations close to that of the virulent strain. No DNA, RNA, or IAA could ever be detected in the inhibition area and, thus, it is almost certain that the inhibiting agent produced by the avirulent strain is not IAA as was previously speculated. This inhibiting agent was insensitive to autoclaving and to the enzymes, pronase, trypsin, DNAse, and RNAse. P. solanacearum bacteriocin was detected by polyacrylamide gel electrophoresis in the medium near the avirulent growth line and not throughout the inhibition area. This supports the conclusion that bacteriocin alone cannot be held responsible for the inhibition phenomenon observed and leaves the nature of this inhibiting agent unknown.
Suppression by Citrus Exocortis Viroid Infection of the Naturally Occurring Inhibitor of the Conversion of 1‐aminocyclopropane‐1‐carboxylic Acid to Ethylene by Tomato Microsomes
Authors: Bellés J. M. , Conejero V. 
Published: May 2008

AbstractCitrus exocortis viroid (CEVd) infection of tomato cell cultures suppresses the constitutive inhibitor which blocks the conversion of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) to ethylene by tomato microsomes. The inhibitor is associated to microsomal membranes and is also found in the water soluble fraction co‐isolated from the cells. The inhibitory effect is concentration dependent, heat stable and could be removed from solution by dialysis. Its possible relationship with regulation of the viroid‐induced ethylene production is discussed.
Effect of Sowing Time on the Incidence of Bud Blight in Soybean (Glycine max L. Merr.)
Authors: Almeida ÁLvaroM. R. , Corso Ivan C. 
Published: May 2008

AbstractThe incidence of soybean bud blight in soybeans in Brazil is sporadic in most of the production areas but is endemic in a few others. Tobacco streak virus (TSV), the causal agent, is transmitted by thrips. The vector population starts declining everytime the amount of accumulated rain is over 300 mm. A four year trial (1986—1990) indicated that by delaying the sowing time it was possible to drastically reduce the incidence of the disease, allowing farmers to grow a cash crop. Significant correlations were observed between percentage of infection, number of days with rain, total of accumulated rain and total of thrips surveyed. A multiple linear regression (y = 23.93 + 0.7 × 1—0.06 × 2) that accounted for 80 % of the variation was obtained, considering percentage of infected plants (y), total of thrips (×1) and total of accumulated rain (×2). Results indicated that farmers should sow during the month of December, in areas where the disease is endemic.
Acquired Resistance in Hypersensitive Tobacco Operates by Limiting Cell‐to‐Cell Spread of Virus Infection without Affecting Virus Multiplication
Authors: Pennazio S. , Roggero P. 
Published: May 2008

AbstractLocalized and systemic acquired resistance against tobacco mosaic virus (TMV) or tobacco necrosis virus was induced when local lesions were produced in leaves of Xanthi‐nc tobacco by mechanical inoculation with TMV. Both types of resistance were characterized by reduction in the size of lesions produced by the challenging viruses, whereas accumulation of viral antigen in lesions was slightly increased. These results, confirming previous findings relative to other hypersensitive plant virus combinations, do not support the view that an inhibitor of virus replication operates in the resistant tissues, but indicate that both types of resistance operate only against cell‐to‐cell spread of virus.
Fusarium oxysporum Forms Heterokaryons with Fusarium redolens
Authors: Rataj‐Guranowska M. , Paszewski A. , Walkowiak I. 
Published: May 2008

AbstractVegetative compatibility among three isolates of Fusarium oxysporum f. sp. lupini and two isolates of F. oxysporum var. redolens from diseased lupins was investigated.Pairings between five mutants originated from each isolate revealed two compatibility groups. The first VCG comprised race 1 of F. oxysporum f. sp. lupini and one isolate of F. oxysporum var. redolens; the second VCG comprised race 2 of F. oxysporum f. sp. lupini and two isolates of F. oxysporum var. redolens. Heterokaryon formation was observed in many pairings involving mutants of both taxa.These findings provide evidence of the conspecificity of these two taxa and they support Gordon's classification (1952) according to which F. redolens is actually F. oxysporum.
Recurrent Selection for Adaptation of Erysiphe graminis f. sp. hordei to Partial Resistance and the Effect of Environment on Expression of Partial Resistance of Barley
Authors: Newton A. C. , McGurk Lynne 
Published: May 2008

AbstractFive isolates of powdery mildew were subjected to recurrent selection on partially resistant barley cultivars and tested at intervals for adaptation to overcome partial resistance. A trend towards adaptation to the recurrent host was observed in infection frequency data, but biomass per colony, measured using sterol cell‐wall determinations and enzyme linked immunosorbent assay, was not greatly affected.The expression of partial resistance was examined after seedling growth under two different environmental regimes. Significant interactions with both overall resistance expression and latent period were detected using infection frequency data, and the effects were both cultivar and isolate dependent.Variability between single colony derivatives of an isolate, which had previously shown adaptation to a partially resistant cultivar, was detected in infection frequency data indicating instability and a non‐nuclear component to adaptation.
Transmission Characteristics of the Clover Phyllody Agent by Dodder*
Authors: Carraro L. , Osler R. , Loi N. , Favali M. A. 
Published: May 2008

AbstractThe results obtained in investigations on the biological characteristics of the clover phyllody agent (CPA) in respect to its transmission by the experimental vector Cuscuta campestris Younk, using Catbarantus roseus L. as constant host, are reported.Transmission efficiency of CPA was comparable whether the “stable bridge” or the “cut strand” of dodder method was adopted. The acquisition and inoculation threshold was between 4 and 6 days. The efficiency of transmission became greater by lengthening the test period up to 15 days. In cuttings of dodder maintained in water after recision, the maximum retention of infectivity, in respect to transmission capacity of CPA, was 28 days. It was proved that CPA invades C. campestris in a persistent manner.In comparative tests between CPA and APA (apple proliferation agent) it was demonstrated that the former is more efficiently transmitted than the latter. Moreover there is a much higher pathogenic effect of APA than CPA in dodder; in fact C. campestris as well as C. subinclusa Dur. and Hilg. develops poorly and shows deformations when growing on AP infected periwinkles. The basic distinguishable symptoms of the two diseases in C. roseus are: virescence and phyllody for CP; small but never virescent flowers for AP. MLOs have been detected, by electron microscopy, in sieve elements of C. roseus and C. campestris infected by CPA.
Identification of Peanut Green Mosaic Virus Strains in India*
Authors: Naidu R. A. , Sreenivasulu P. , Manohar S. K. , Ramakrishna K. N. , Reddy D. V. R. , Nayudu M. V. 
Published: May 2008

AbstractDuring field surveys, three peanut green mosaic virus isolates differing in symptomatology on groundnut and a few other hosts were collected. Ultrathin sections of infected groundnut leaflets showed cytoplasmic inclusions with pin wheels and scrolls. In enzyme‐linked immunosorbent assay they reacted strongly with antisera to peanut green mosaic and soybean mosaic virus antisera, and moderately with adzuki bean mosaic and peanut stripe virus antisera. All isolates also reacted positively with antisera to peanut eye spot, blackeye cowpea mosaic, pea seed‐borne mosaic, potato virus Y and tobacco etch viruses, and did not react with antisera to peanut mottle, bean yellow mosaic, bean common mosaic, clover yellow vein and sugarcane mosaic viruses. SDS‐PAGE analysis of purified virus preparations of the three isolates showed a single polypeptide with mol. wt. of 34,500 daltons. Based on these results, the three isolates are identified as biologically distinct strains of peanut green mosaic virus.
The Effect of Ultraviolet and Solar Radiation and Temperature on Survival of Fungal Propagules
Authors: Rotem J. , Aust H. J. 
Published: May 2008

AbstractSurvival of spores, spore aggregates, sclerotia, and pycnidia of fungi was evaluated after exposure to high temperature in the dark, or exposure to ultraviolet (UV) radiation or sunlight. Under most conditions survival decreased from the most resitant Sclerotium rolfsii to Alternaria macrospora, Mycosphaerella pinodes, Aspergillus niger and Botrytis cinerea, in that order. There was no difference in survival among organisms stored in darkness at 45°C as single spores or aggregated into a mass of spores; or between spores of M. pinodes exposed before and after being released from pycnidia. Exposure to UV reduced survival much more than exposure in darkness. Longevity under UV ranged from more than 7 days for S. rolfsii to approximately 50 min for A. macrospora and 3 min for B. cinerea. Much longer survival occurred for spores of all fungi aggregated together; of spores of M. pinodes irradiated when inside rather than outside pycnidia; and in bigger, darker and older rather than in smaller, paler and younger sclerotia of S. rolfsii. Survival of sclerotia cut into slices and exposed to UV increased with thickness, irrespective of exposure to UV with the outer pigmented or innernonpigmented side. As tested with spore aggregates of A. niger, the rate of survival was linearly proportional to the number of conidia aggregated in each body. Irradiation by sunlight affected survival as described for irradiation by UV. The best protection from the detrimental effects of sun and UV radiation was provided by the infected host tissue.
Variability in the Sensitivity of Rhizoctonia solani Anastomosis Groups to Fungicides
Authors: Kataria HansR. , Verma P. R. , Gisi Ulrich 
Published: May 2008

AbstractTolclofos‐methyl, iprodione and cyproconazole, among the eleven fungicides tested in vitro, gave consistently strong inhibition against all ten anastomosis groups (AGs) of Rhizoctonia solani. Carboxin, furmecyclox, thiabendazole, fenpropimorph and vinclozolin also inhibited all AGs but with wide variations in toxicity levels (EC90 values). Pencycuron showed strong activity against four AGs but was ineffective against the other six AGs. Generally, R. solani AGs were insensitive to fenarimol and imazalil. Tolclofos‐methyl strongly inhibited 23 AG2‐1 and 20 AG4 rapeseed/canola R. solani isolates from different locations in Saskatchewan, Alberta and Manitoba. The same isolates were also sensitive to iprodione, cyproconazole and carboxin. All AG4 canola isolates were insensitive to pencycuron (EC90 > 500 mg/l) while AG2‐1 isolates showed highly variable levels of sensitivity with EC90s ranging from 0.5 to 220 mg/l. Tolclofos‐methyl, applied to Brassica napus (canola) cv. Westar seed at 1 g a.i./kg, provided 75—100 % control of seedling damping‐off in pots infested with AG2‐1 or AG4 isolates. In parallel experiments, pencycuron (1 g a.i./kg seed) failed to control damping‐off by AG4 canola isolates and gave variable disease control against AG2‐1 isolates.
The Effect of Bacillus subtilis on In Vitro Growth and Pathogenicity of Erwinia amylovora
Authors: El‐Goorani M. A. , Hassanein F. M. 
Published: May 2008

AbstractFive isolates of Bacillus subtilis were found to be antagonistic to 3 isolates of Erwinia amylovora in vitro on sucrose agar medium. However, B. subtilis or its culture filtrate did not exhibit any activity against E. amylovora in planta tests in the laboratory on immature green pear fruits or in a commercial pear orchard under natural growing conditions.
Fatty Acid Composition of Pseudomonas syringae pv. savastanoi
Authors: Wells J. M. , Casano F. J. , Surico G. 
Published: May 2008

AbstractOver 85% of total cellular fatty acids of 30 strains of P. syringae pv. savastanoi, grown for one day at 28 °C on King's medium B (KB) agar, were 12:0 (5.0%), 16:0 (27.5%), 16:1 (36.7%) and 18:1 (16.8%). Three hydroxy‐substituted fatty acids comprised 7.2% of the total and 22 other minor components, each occurring at concentrations of less than 1%, comprised an additional 4%. Three percent were unidentified components. Cells grown for 3 and 6 days on KB agar contained lower concentrations of the unsaturated 16:1 (30.4 and 21.1%, respectively), and higher concentrations of branched‐chain and cyclopropane fatty acids than one‐day old cells. No consistent differences in fatty acid composition could be detected between virulent and avirulent strains, nor between pv. savastanoi and other pathovars of P. syringae. However, when cells were grown on a chemically‐defined medium for 6 days, concentrations of 16:0 and a tentatively‐identified 17‐carbon hydroxy fatty acid were higher, and those of 12:0 and 16:1 were lower in strains from Fraxinus than from Olea. P. fluorescens (7 strains) and P. viridiflava (6 strains) could be differentiated from each other but not from P. syringae.