bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Post‐infection Application of Fungicides on the Apple Scab Pathogen, Venturia inaequalis (Cke.) Wint.
Authors: Thakur V. S. , Gupta C. K. , Garg I. D. 
Published: May 2008

AbstractThe Ergosterol‐biosynthesis inhibiting (EBI) fungicides had a prolonged inhibitory effect on the growth and sporulation of the fungus, Venturia inaequalis thereby preventing development of typical apple scab symptoms. Atypical lesions in the form of chlorotic or reddish brown flecks had reduced viable sporulation with deleterious effect on subcuticular hyphae when fungicide was applied beyond 144 h but before 170h after inoculation. Myclobutanil (45μg a.i./ml) had the maximum inhibitory effect on sporulation and colony growth while bitertanol (187.50 μg a.i./ml) showed only a temporary inhibition of fungal growth and sporulation. Ultra‐structural studies also exhibited different levels of fungitoxicity by different fungicides when applied 144 h after inoculation.
Tomato Mosaic Virus Infection in a Recirculating Nutrient Solution
Authors: Pares R. D. , Gunn L. V. , Cresswell G. C. 
Published: May 2008

AbstractWe studied the behaviour of tomato mosaic tobamovirus (ToMV) in a recirculating nutrient solution. Particles of tomato mosaic virus were found in the nutrient solution 3 days after leaf inoculation of plants and we demonstrated that the level could increase to a concentration readily detectable by electron microscopy. Virions remained infective in nutrient solution for at least 6 months, could infect bait plants and induced systemic symptoms within 10 days. This is the first report of measurement of infective virions in recirculating nutrient solutions. Hydroponic producers should be aware of the potential for rapid spread of virus diseases in soilless growing systems as one infected plant can serve as a source of inoculum that can ultimately result in an epidemic.
Location of Oospores in Buckwheat Seed and Probable Roles of Oospores and Conidia of Peronospora ducometi in the Disease Cycle on Buchwheat
Authors: Zimmer R. C. , McKeen W. E. , Campbell C. G. 
Published: May 2008

AbstractOospores of Peronospora ducometi, the causal agent of downy mildew of buckwheat (Fagopyrum esculentum), were found in the calyx remnant attached to the seed, on the inside of the seedcoat and in the spermoderm layer between the seedcoat and the endosperm. This constitutes a first report documenting the location of oospores in buckwheat seed. Systemic infection of seedlings occurred from oospore‐infested seed. Conidial germination was greater at 14°C than 25°C. Systemic infection also occurred as the result of conidial infection of leaves.It is proposed that primary infection of buckwheat occurs by the germination of seed‐borne oospores resulting in systemic invasion of the seedling by the germtubes, and followed by conidial formation on the cotyledons. Secondary infection occurs initially from conidia produced on the cotyledons as a result of the systemic infection from seed and subsequently as the result of repeated infections by conidia produced on leaf lesions as the disease progresses up the plant.
Artificial Induction and Evaluation of a Mild Isolate of Tomato Spotted Wilt Virus
Authors: Wang Min , Gonsalves Dennis 
Published: May 2008

AbstractA severe isolate (BL) of tomato spotted wilt virus (TSWV) that originated from Hawaii was treated with nitrous acid in an effort to obtain mild mutants. The standardized procedure used in mutation experiments was: extracting infected Gomphrena globosa L. leaf tissue in 0.01 M Na2SO3, 0.125 M sodium acetate and 0.4 M sodium nitrite at pH 5.5 and incubating the extract for 20 min at room temperature. The extract was inoculated to tobacco (Nicotiana tabacum L. cv. Havana 423) and local lesions were subsequently transferred to lettuce (Lactuca sativa L. cv. Minetto). One isolate (R27G) that incited mild symptoms in lettuce was obtained out of 868 local‐lesion‐transfers. Under greenhouse conditions, the isolate induced mild symptoms on tomato (Lycopersicon esculentum Mill.) but was severe on peppers (Capsicum annuum L.). The effect of the R27G isolate on growth of potted tomatoes kept outdoors was variable. In one trial, only 15 % of the fruit had symptoms versus 67 % in another trial. R27G fully protected Datura stramonium L. plants that were challenge inoculated with the severe parent BL isolate. Less effective cross protection was observed against a severe isolate from Oklahoma.
Determination of the Antigenic Protein Size Associated with Faba Bean Phyllody MLO by Using (SDS‐PAGE) Electrophoresis and Immunotransfer
Authors: Saeed Essam , Rage Pierre , Cousin Marie‐Thérégse 
Published: May 2008

AbstractThe antigenic proteins of MLO associated with faba bean phyllody (FBP) occurring in the Sudan were studied by using SDS‐PAGE electrophoresis followed either by silver nitrate staining or by transferring to nitrocellulose membrane probed with specific polyclonal antiserum. No remarkable differences between healthy and FBP infected plants were observed when the gel was colored with silver nitrate. In contrast, after probing the transferred membrane with the specific polyclonal FBP antisera, band formation was only detected with FBP infected plants. These results were treated through an image analyser using a BIOLAB logicial. The analysed proteins measure approximately 18,000 and 36,000 daltons with regard to the protein molecular weight niarkers used (Bio‐Rad). Possibility of the existence of a dimer is discussed. The localization of the bands is the same whatever the origins of FBP: Vicia faba or Crotalaria saltiana. However, the partial purification of the MLO including differential centrifugations followed by precipitation with polyethylene glycol (PEG) and passage through a column of Sepharose 4B were found to be essential for having clear electrophoretic profiles.
The Isolation and Evaluation of Two Naturally Occurring Mild Strains of Vanilla Necrosis Potyvirus for Control by Cross‐Protection
Authors: Liefting Lia , Pearson Michael , Pone Semisi 
Published: May 2008

AbstractIn an attempt to find mild virus strains that would cross‐protect sgainst vanilla necrosis potyvirus (VNPV), Vanilla fragrans plants in Tonga were surveyed for the presence of mild or symptomless potyvirus infections. Potyviruses were detected by indirect ELISA using a commercially available portyvirus group monoclonal anibody. From 28 plants with mild or symptomless infections two portyvirus isolates, designated V1 and V3, included systemic infections in Nicotiana benthamiana following mechanical inoculation. V1, which causes a mild mottle in N. benthamiana, is serologically related to VNPV, while V3 which causes mild vein banding is serologically unrelated to VNPV. Prior inoculation with V1 protected N. benthamiana against the severe mosaic symptoms of VNPV when challenge inoculated after 14 and 21 days, but not after 7 days. When V3 was used as the protecting strain, cross‐protection was observed in some, but not all plants, when chalenged with VNPV after 14 and 21 days.
Temporal and Spatial Development of Papaya Ringspot in Veracruz, Mexico
Authors: Mora‐Aguilera Gustavo , Téliz Daniel , Campbell C. Lee , Avila Catarino 
Published: May 2008

AbstractThe temporal progress and spatial distribution of papaya ringspot virus (PRV) and populations of aphid vectors were monitored in two papaya (Carica papaya) plantations in the state of Veracruz, México. The incidence of PRV had a typical sigmoidal curve and the logistic model was more acceptable for describing the disease progress than the Gompertz model. The rate (rL of increase in disease incidence (0.034 and 0.023/unit/day in Plot A and B, respectively) differed (P = 0.05) between the plots; differences in number of aphids trapped could account for the difference. The initial determination of an apparent regular spatial pattern early in the epidemic, obtained with a quadrat size determined by Greig‐Smith's method (n = 8 plants/quadrat) at 50 % disease incidence, was inconsistent with our biological observations in the field. An arbitrarily selected, square quadrat size (n = 9 plants/quadrat), was more consistent with visual observation for describing the spatial pattern in the field. With 9 plants/quadrat a random pattern was found. Aphid populations had a bimodal distribution at both sites with the highest population peak in December–February and a secondary peak in August–September and change in disease incidence was generally related to the aphid population level in the previous month. None of the five potential aphid vectors (Myzus persicae, Aphis gossypii A. nerii, A. citricola and Macrosiphon euphorbiae) of PRV in Mexico colonized the papaya plants, however, which may explain the absence of clustering of disease.
Comparing the Effects of Rust on Plot Yield, Plant Yield, Yield Components, and Vegetative Parts of Soybean
Authors: Yang X. B. , Dowler W. M. , Tschanz A. T. , Wang T. C. 
Published: May 2008

AbstractTo determine the plant variable for coupling a disease model to a soybean growth model, effects of soybean rust (caused by Phakopsora pachyrhizi) on soybean were quantified at four levels: vegetative parts, yield components, plant yield, and plot yield. Path analysis was conducted to determine the most correlated components to disease in each level. The responses of vegetative parts, such as shoot weight and branches/plant, to disease effects were inconsistent among cultivars. Yield components responded consistently to disease effects among the cultivars, indicated by the high values of correlation coefficients between disease and the components. Path coefficients indicated that reduction of 100‐seed weight was the most important cause of yield loss in this level. No significant within‐plant compensation was detected using path coefficient analysis except for that between pod length to pod width. The most consistent response to disease effect was at population level. Correlation of disease to plant yield was as significant as these to plot yield. Correlations between disease and these plant levels were in the order of plot yield, plant yield, yield components, and vegetative parts. Regression between plot yield and green leaf area duration (GLAD) from flowering to seed full size was highly significant (P < 0,001). This study suggests that green leaf area at population level was the best variable for coupling disease model to crop model.
Infektionsstrukturen von Microdochium bolleyi an Wurzeln und Koleoptilen von Gerste
Authors: Hemens E. , Steiner U. , Schonbeck F. 
Published: May 2008

AbstractInfection structures of Microdochium bolleyi on barley roots and coleoptiles Microdochium bolleyi grows within roots and coleoptiles of barley either leading to a damage of the tissue or to a symptomless infection. The present work investigated whether these different types of infection are correlated with different infection structures of the fungus. Two types of hyphae were formed infectmg either the rhizodermis or the epidermis. The fungus spread within the cortex only, not affecting the endodermal cells or the vascular tissue. The extend to which the roots were damaged depended on the infection density. Differences in the structure of hyphae formed in symptomless or necrotic parts of the roots were not observed. In both, roots and coleoptiles, hyphae were detected in dead cells only.
The Activation of Latent Infections of Monilinia fructicola on Apricots by Volatiles from the Ripening Fruit
Authors: Cruickshank R. H. , Wade G. C. 
Published: May 2008

AbstractLatent infections produced by Monilinia fructicola on green apricot fruit are separated from aqueous contact with live host tissues by hydrophobic suberin. However, they respond to host ripening and become invasive. The time and intensity of production of the volatile compounds acetaldehyde and ethanol during fruit ripening strongly correlated with both the invasive outbreak of mycelium from arrested lesions, and with the stimulation of growth of germ tubes in vitro in the presence of fruit volatiles. Latent infections on green apricots were activated to escape from the lesions in response to exposure to those volatiles in the concentration detected from ripe apricots. However, the tissue of green apricots was stimulated to fresh necrosis and general fruit invasion did not occur.
Random Primer Dependent PCR Differentiates Aggressive from Non‐Aggressive Isolates of the Oilseed Rape Pathogen Phoma lingam (Leptosphaeria maculans)
Authors: Schäfer C. , Wöstemeyer J. 
Published: May 2008

AbstractA number of isolates of the aggressive an d non‐aggressive pathotype group of the rape seed (Brassica napus) pathogen Phoma lingam (teleomorph: Leptosphaeria maculans) were analyzed by means of a simple, random primer dependent PCR (polymerase chain reaction) approach. Using the four synthetic nona‐ and decamer oligonucleotides 5′‐GGAGCCCAC‐3′, 5″‐ACGGTCTTGG‐3′, 5′GAAACAGCGG‐3′, and 5′‐GGCATCGGCC‐3′ informative bands for both of the pathotype groups could be obtained. These amplified bands were shown to originate not only from repeated but also from single and low copy target sequences. This is the first report on molecular diagnostics of a plant pathogenic fungus, based on random primer dependent PCR. The experimental system is fast and reliable, does not require cloning and sequencing of L. maculans DNA, and works without time‐consuming blotting or hybridization steps.
Development of a Method to Obtain Monospecific Antibodies Directed Against a 31 kD Protein of Pseudomonas syringae pv. syringae
Authors: Niepold F. 
Published: May 2008

AbstractWe describe a simple method of purifying Pseudomonas syringae pv. syringae (P. s. pv. s.) specific polyclonal antibodies which are directed against a cell surface protein sized 31 kD. The actual purification step of the polyclonal antibodies occurs with denatured proteins after an SDS‐PAGE gel electrophoresis and western blotting. Polyclonal antibodies were obtained which recognized a 31 kD protein. On a western blot no cross reaction of the purified polyclonal ‘monospecific 31 kD antibodies’ with other proteins from the same strain was observed. However, a positive “monospecific 31 kD antibody” reaction was only visible when either protein extracts from several selected pathogenic P. s. pv. s. strains from different hosts, or two isolates of Pseudomonas syringae pv. pisi (P. s. pv. p.) were used. An indication that this 31 kD protein is specific to P. s. pv. s. is that no cross reaction was found with protein extracts from the tested pathogenic and non‐pathogenic pseudomonads. However, a differentiation of the tested P. s. pv. s. and P. s. pv. p. isolates was possible when cells were grown above 30 °C. Then protein extracts from P. s. pv. s. revealed the lack of the 31 kD protein but not P. s. pv. p. protein extracts. Polyclonal antibodies raised in rabbits against the 31 kD protein band from the western blot proved to be specific enough to agglutinate whole P. s. pv. s. strain R32 cells or for detecting a single 31 kD protein band on a western blot when whole cell protein extracts of P. s. pv. s. strain R32 were used.
Inhibition of Rust Diseases of Cereals by Metabolic Products of Verticillium chlamydosporium
Authors: Leinhos G. M. E. , Buchenauer H. 
Published: May 2008

Abstract Verticillium chlamydosporium produced in submers culture several antifungal and/or phytotoxic compounds which were detected in a bioassay by using the pathogen‐host system Puccinia coronata and oat seedlings. The antifungal compounds were also tested against P. recondita on wheat and P. sorghi on corn seedlings. The production of the active metabolic compounds highly depended on the nutrient solution (peptone‐Czapek [PC] and malt extract [ME]) and on the fermentation times. Cell‐free filtrates of PC‐cultures of the fungus were highly phytotoxic; the fungitoxic and phytotoxic compounds were heat‐labile and dialyzable. The ethyl acetate extracts of the PC‐culture filtrates contained only the antifungal active substances. The antifungal compounds in ME‐culture filtrates proved to be heat‐stable, could be dialyzed and extracted with ethyl acetate. Ethyl acetate extracts of PC‐ and ME‐culture filtrates at concentrations of 500 μg/ml reduced rust disease incidence by up to 80 % compared to the control treatment.Further studies with extracts of ME‐culture filtrates displayed a distinct protective but no systemic activity. The extract interfered with the development of several infection structures of the rust fungi, mostly with the growth of germ tubes as well as with the formation of the aappressoria and haustorial mother cells. Three rust‐active fractions were obtained by preparative layer chromatography on silica gel. One of these fractions exhibited phytotoxic activity. The most active antifungal fraction is identical with the macrolid antibiotic monorden which caused a desorientated spiral growth in P. coronata germlings on oat leaves.
The Role of Phytophthora cryptogea and Waterlogging in Root Rot Kiwifruit
Authors: Stewart A. , McCarrison A. M. 
Published: May 2008

AbstractA 48 h or 96 h period of waterlogging induced a partial rotting of the root system of 18 month old potted kiwifruit cuttings. However, root regeneration compensated for the loss of damaged roots and the plants remained healthy. Inoculation with Phytophthora cryptogea under low soil moisture conditions caused a small amount of root rotting (11 %) and regeneration of the roots occurred. Root rot was significantly increased when inoculations were combined with extended periods of waterlogging. Root rot incidence was highest (89 %) in inoculated plants exposed to periods of 96 h waterlogging. Regeneration did not occur with any of these plants and consequently, the shoot systems were severely damaged.
Effects of Commercial Fatty Acids on Cutinase Release by Ascochyta pisi
Authors: Nasraoui B. , Lepoivre P. , Semal J. 
Published: May 2008

AbstractThe effect of a range of commercially available C16 and C18 fatty acids, on the release of cutinase by Ascochyta pisi, was studied. When juniperic acid was used as sole carbon source, cutinase activity was released in the culture medium, and was markedly enhanced by post‐treatment of A. pisi cultures with acetone used as enzyme extractor. Without acetone, less cutinase was naturally released in culture medium containing juniperic acid at 0.5 %, than at 0.0l % or 0.05 %. Upon post‐treatment with acetone, the same level of cutinase was released with all three concentrations, thus suggesting that the enzyme was induced, but not completely released in the presence of 0.5 % juniperic acid. When ricinelaidic or ricinoleic acids were supplemented at 0.5 % to cutin in the culture medium, they strongly inhibited the release of cutinase, even with acetone post‐treatment. Comparable inhibition by ricinoleic acid was also observed when juniperic acid was used as cutinase inducer, thus suggesting that not only the release, but also the production of cutinase were inhibited.
Mycoplasma‐like Organisms in Phloem Elements of Ammobium alatum
Authors: Chang K. F. , Mirza M. , Hwang S. F. 
Published: May 2008

AbstractUsing transmission electron and fluorescent microscopes, Mycoplasma‐like organisms (MLOs) were found in phloem cells of stems and leaves of Ammobium alatum. The diameter of these organisms ranged from 0.12–0.73 μm and averaged 0.4 μm. Symptoms induced by MLOs included chlorosis and reddening of leaves and winged stems, plant stunting and flower phyllody. This is the first report of MLOs associated with disease symptoms in A. alatum.
Isolation and Partial Characterization of a Tenuivirus from Wheat in Iran
Authors: Heydarnejad J. , Izadpanah K. 
Published: May 2008

AbstractA tenuivirus, tentatively designated Iranian wheat stripe virus (IWSV), was transmitted by the delphacid Unkanodes tanasijevici and induced dwarfing, striping and yellowing symptoms in wheat. It could also infect barley, oat, rice, rye, sorghum and a number of other gramineous species. The virus was purified from wheat by chloroform clarification and differential and density‐gradient centrifugation. It formed several layers in density‐gradient columns. Purified virus preparations had a UV absorption spectrum typical of nucleoproteins and contained flexuous supercoils of 8.7 nm and fine filaments of 4.3 nm width. The antiserum produced against the virus reacted with infected plant sap in agar‐gel diffusion and enzyme‐linked immunosorbent assay (ELISA). The virus could be readily detected in individual viruliferous planthoppers by ELISA. IWSV was serologically related to rice hoja blanca virus but not to maize stripe virus. The relationship of IWSV with other tenuiviruses is discussed.
Growth Characteristics in Cultured Cucumber Tissues Infected with Hop Stunt Viroid
Authors: Takahashi T. , Ghiba K. , Ozaki R. , Sadakata H. , Andoh Y. , Yoshikawa N. 
Published: May 2008

AbstractLeaf disks from hop stunt viroid (HSVd)‐infected cucumber plants and healthy controls were cultured in vitro under different auxin/cytokinin regimes. Amounts of tissue growth and root formation were consistently reduced as a result of HSVd infection. Histological observations indicated that anomalies in the distribution of peripheral meristems and tracheary elements associated with cambial cells might be involved in the hypoplastic syndrome incited by HSVd.
Fatal Yellowing of Oil Palms: Search for Viroids and Double‐Stranded RNA
Authors: Beuther E. , Wiese U. , Lukáacs N. , van Slobbe W. G. , Riesner D. 
Published: May 2008

AbstractFatal yellowing is a serious disease of still unknown origin affecting oil palms in several regions of Central and South America. In this study a search for viroids and viroid‐like RNAs in oil palms was performed using two‐dimensional gel electrophoresis and return gel electrophoresis of nucleic acid extracts. Although RNAs showing viroid‐like gel‐electrophoretic properties were detected, the presence of the known viroids was excluded by hybridization experiments using probes specific for potato spindle tuber viroid (PSTVd), coconut cadang‐cadang viroid (CCCVd), or Coleus blumei viroid 1 (CbVd1). By using double‐stranded RNA (dsRNA) specific monoclonal antibodies, which do not react with viroid RNA, we were able to show that oil palm RNAs, migrating like viroids are double‐stranded RNA species. Since the same dsRNA pattern was found in extracts from diseased as well as from healthy oil palms, the dsRNAs can neither be part of the causative agent of fatal yellowing, nor are they associated with the disease. Their possible origin is discussed. In addition to the standard electrophoretic methods, which have been used for identification of viroids and viroid‐like RNAs, we describe additional control experiments to differentiate unequivocally between circular single stranded and linear dsRNA.
Ultrastructural Histopathology of Infection and Colonization of Maize by Stenocarpella maydis (= Diplodia maydis)
Authors: Bensch M. J. , Van Staden J. 
Published: May 2008

AbstractThe mode of penetration and colonization of stalk, shank and leaf sheath tissues of maize by Stenocarpella maydis (=Diplodia maydis) was determined by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) observations. Detached plant tissues, inoculated with a conidial suspension and examined by SEM at various intervals, showed that S. maydis conidia germinated on all plant material types after 5 h incubation at 30 °C. After 72 h incubation, appressoria had formed at the hyphal tips. Similar observations were recorded on plants inoculated in the glasshouse except that germination was delayed by 7 days after inoculation. TEM studies showed that penetration was affected by a penetration hypha which resulted in the inter‐ and intracellular colonization of the plant tissues. Colonization was accompanied by degradation of cell walls suggesting that host colonization is facilitated by enzyme activity.