bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rhizoctonia solani Incited Damping‐off in Radish Suppressed by Plasmid and Non‐plasmid Carrying Strains of R. solani that Enhance Host Chitinase Activity
Authors: Tschen J. S.‐M. , Chen C.‐S. , Hsue C.‐C. , Ling Y.‐L. , Cheng Y.‐H. 
Published: May 2008

AbstractThirteen Rhizoctonia solani isolates belonging to anastomosis group four were examined. All of the isolates carry plasmids except isolates CHU344 and CHU345. Plasmids were analysed by agarose gel electrophoresis and observed by transmission electron microscope. The plasmid DNA is linear, having a size of 2.6 kbp. The termini of the plasmid have a hairpin structure. The replication of plasmid DNA of R. solani CHU341 (pCHU341) was demonstrated by electron microscopy.Virulence of the fungi was tested on radish seedlings and expressed according to percentage of radish seedlings that damped‐off. Strains CHU341, CHU344, CHU345, CHU346, CHU347, CHU348, CHU350 and CHU353, suppressed damping‐off of radish seedlings by the virulent isolates, CHU342, CHU349, CHU351 or CHU352 and was expressed according to a suppressiveness index. The chitinase activities of radish seedlings increased from 10 to 20 times after inoculation with suppressive isolates, CHU341, CHU344 and CHU345.The results indicate that damping‐off of radish seedlings caused by R. solani can be protected by related strains with or without plasmids. The protection of the seedlings may result from the enhancement of chitinase activities induced by the suppressive strains of R. solani.
Natural Infection of Field‐Grown Daikon Radish (Raphanus sativus L.) Crops by Turnip Crinkle Virus in North America
Authors: Reddick B. B. , Putnam M. L. , Habera L. F. 
Published: May 2008

AbstractIn 1993, stunted field‐grown daikon radish plants were found with black lesions on the petioles and leaf blades, and new growth exhibited leaf crinkling and a mosaic pattern on distorted leaves. The plants had hollow roots and seed production was severely reduced. Symptomatic plants contained isometric virions identified as those of turnip crinkle virus (TCV). This is the first report of TCV causing serious economic damage and the first report of natural infection in North America.
Biological Control of Damping‐off of Cucumber caused by Pythium ultimum with a Root‐Colonization‐Deficient strain of Escherichia coli
Authors: Roberts D. P. , Dery P. D. , Hebbar P. K. , Mao W. , Lumsden R. D. 
Published: May 2008

AbstractSuppression of damping‐off of cucumber and root colonization was compared for strain 501R3 of Enterobacter cloacae and strain S17R1 of Escherichia coli, a rifampicinresistant mutant of E. coli S17‐1. Both strains 501R3 and S17R1 provided effective biocontrol of pre‐emergence and post‐emergence damping‐off of cucumber caused by Pythium ultimum when applied as seed treatments containing approximately 107 cfu per seed. Plant stands from seeds treated with 501R3 or with S17R1 were 93% and 92%, respectively (similar at P ≥ 0.05), when sown in soil‐less mix infested with P. ultimum. The plant stand with the pathogen control was only 30%—significantly less (P ≥ 0.05) than stands from the 501R3 and S17R1 treatments. Cucumber was only briefly susceptible to damping‐off caused by P. ultimum since seeds pregerminated for 29 h or longer before sowing in P. ultimum‐infested soil‐less mix yielded plant stands similar to the healthy control treatment. Plant stands from nonpregerminated seeds were significantly less (P ≥ 0.05) than pregerminated seed treatments. E. coli strain S17R1 was not an effective colonizer of cucumber rhizosphere. When applied as seed treatments containing approximately 104 or 108 cfu per seed, populations of strain S17R1 were significantly smaller (P ≥ 0.05) than with corresponding treatments of strain 501R3 at 24, 48, 72 and 96 h after sowing in soil‐less mix. Populations of strain S17R1 increased only 65‐fold over 96 h when applied at 104 cfu per seed. In contrast, populations of strain 501R3 increased 24000‐fold over the same period when applied at 104 cfu per seed. Populations of strain S17R1 were limited to the upper 1 cm of cucumber root at 7 days and decreased to approximately 101 cfu/g of total root system over 42 days. Strain 501R3 was capable of becoming widely distributed along cucumber roots and was detected at populations of approximately 108 cfu/g of total root system at 42 days. Results from this study indicate that E. coli is capable of suppressing damping‐off of cucumber caused by P. ultimum. In addition, extensive root colonization by E. coli strain S17R1 was not required in this biocontrol interaction because of the brief period of susceptibility of cucumber to this disease.
Bacterial Blister Bark of Apple Trees in Italy
Authors: Scortichini M. , Morone C. 
Published: May 2008

AbstractAt the beginning of spring 1996, raised, brown areas along the bark of trunk and twigs were observed on young apple trees in Piedmont (northern Italy). In many cases the epidermis flaked off. Longitudinal cracks accompanied by necrosis of the tissues beneath the bark were also observed. In one orchard the disease caused the death of 2500 trees. Biochemical, nutritional and pathogenicity tests, as well as the comparison of whole‐cell protein profiles of the isolates with type‐strains, indicated that Pseudomonas syringae pv. syringae was the causal agent of the disease. Bacterial blister bark remains a threat for apple cultivation also in Italy, especially in orchards planted in sandy soils.
Inheritance of Virulence of Venturia inaequalis Toward Mains×domestica Cultivars
Authors: Sierotzki H. , Gessler C. 
Published: May 2008

AbstractThe resistances of the three apple cultivars ‘Boskoop’, ‘Spartan’, and ‘Golden Delicious’ were differential to the isolates Bo‐7 and Sp‐7 of Venturia inaequalis. Isolate Bo‐7 was virulent towards ‘Boskoop’ and ‘Golden Delicious’ not to ‘Spartan’, and Sp‐7 was only virulent toward ‘Spartan’, suggesting that a gene‐for‐gene relationship is working in this pathosystem. The two isolates were hybridized in order to determine the genetic basis of virulence. All theoretically possible phenotypes were found in 33 ascospore progenies from two selected strains carrying virulence towards ‘Boskoop’ and ‘Spartan’, with 14 progenies virulent towards ‘Boskoop’. 9 virulent to ‘Spartan’. and 15 virulent to ‘Golden Delicious’. Seven progeny were avirulent to all three cultivars, which is in agreement with the theoretical number of isolates with three avirulences. The segregation of virulence and avirulence among the progeny towards ‘Boskoop’. ‘Spartan’, and ‘Golden Delicious’ fit best to the hypothesis that one gene is responsible for virulence to ‘Boskoop’ and ‘Golden Delicious’ and that two genes are responsible for virulence towards ‘Spartan’, assuming that each gene segregated independently from the other genes. The two genes for virulence to ‘Spartan’ were complementary and were inherited independently. Virulence of V. inaequalis is governed by few heritable genes for each cultivar. Combinations of virulences are observed, indicating that the building‐up of complex races is possible.Zusammenfassung Vererbung der Virulenz gegenüber Apfelsorten in Venturia inaequalis Die Isolate Bo‐7 und Sp‐7 von Venturia inaequalis sind dilferentiell zu den Apefelsorten ‘Boskoop’. ‘Spartan’ und ‘Golden Delicious’. Das Isolat Bo‐7 ist virulent auf ‘Boskoop’ und ‘Golden Delicious’ und Sp‐7 ist nur virulent auf’ Spartan’. Die Nachkommenschaft von 33 Isolaten spalteten in alle theoretisch möglichen Phänotypen auf: 14 Nachkommen sind virulent auf ‘Boskoop’, 9 auf ‘Spartan’ und 15 auf ‘Golden Delicious’. Sieben Nachkommen sind avirulent auf alien drei Sorten, was mit dem errechneten Wert übereinstimmt. Die Segregationsdaten für Virulenz und Avirulenz gegenüber den drei Sorten zeigen. Daß die Virulenz gegenüber ‘Boskoop’ und ‘Golden Delicious’ von einem Gen und die Virulenz gegenüber ‘Spartan’ von zwei Genen bestimmt wird. Die Gene werden unabhängig voneinander vererbt. Die beiden Gene für die Virulenz gegenüber ‘Spartan’ sind komplementär und unabhängig vererbt. Virulenzkombinationen wurden beobachlet, was auf die Möglichkeit der Entstehung von kimplexen Rassen schliessen lässt.
Genetic Analysis of a Cross of Two Venturia inaequalis Strains that Differ in Virulence
Authors: Sierotzki H. , Gessler C. 
Published: May 2008

AbstractA genetic map of the fungus Venturiainaequalis based on the Bo‐7 × Sp‐7 cross linking 30 RAPD‐PCR markers to the ITS‐region, the mating‐type locus and the virulence/avirulence to the apple cultivar ‘Boskoop’ was constructed. The map covers 270 cM and is divided into six linkage groups. The mating‐type locus is flanked by two RAPD‐PCR markers in 28.9 and 18.9 cM distance. The ITS‐region is located on one chromosome, spans a length of 7.16 cM and is linked to a RAPD‐PCR marker at 15.7 cM distance. The virulence/avirulence to ‘Boskoop’ is linked to a RAPD‐PCR marker at 19.5 cM. Virulence to ‘Golden Delicious’ is unlinked. The relative positioning (linked or unlinked) of virulence/avirulence genes is important for the adaptation of V. inaequalis strains to new introduced host resistances or lo new combinations of host resistances genes.Zusammenfassung Genetische Analyse einer kreuzung zwtier Venturia inaequalis Stämme mit unterschiedlicher Virulenz Durch die Kopplung von 30 RAPD‐PCR Markern, der ITS‐Region, dem ‘Mating’‐Typ und der Virulenz gegenüber ‘Boskoop’ wurde eine genetische Karte von Venturia inaequalis basierend auf der Kreuzung Bo‐7 × Sp‐7 erstellt. Die Karte ist 270 cM lang und in sechs Gruppen unterteilt. Der ‘Mating’‐Typ Locus ist von zwei RAPD‐PCR Markern eingeschlossen in 28.9 und 18.9cM Entfernung. Die ITS‐Region und mit ihr die r‐DNS ist auf einem Chromosom lokalisiert und ist 7.16 cM lang. Die ITS‐Region ist in 15.7 cM Entfernung zu einem Marker gekoppelt. Die Virulenz gegenüber ‘Boskoop’ ist in 19.5 cM zu einem Marker gekoppelt.
Critical review of Identification Techniques for Armillaria spp. and Heterobasidion annosum Root and Butt Rot Diseases
Authors: Schulze S. , Bahnweg G. 
Published: May 2008

AbstractThe need for a rapid and definite diagnosis of the Armillaria spp. and Heterohasidion annosum root and butt rot diseases as well as general requirements expected of a test to detect the pathogens are reviewed. As a spin‐off from more fundamental molecular biological research there has been a remarkable increase in new methods for diagnosis (i.e. detection and identification) in recent years. These new methods all have in comtnon that they use strtjctural elements of the target organisms such as proteins, polysaccharides, glycoproteins, nucleic acids, etc. for the construction of antibodies, probes and primers for detection, or to produce electrophoretic patterns to be used for classification and identification. This paper presents a short review of principles, advantages, disadvantages and some perspectives of the new methods developed for Armillaria spp. and H. annosum diagnosis compared with conventional ones, such as interfertility testing or visual inspection of the pathogens in situ and in vitro in pure culture. It will be noted that the specificity and reproducibility of the new techniques, which are closely linked with potential experimental error, lead to principal pitfalls which should be kept in mind when conclusions are drawn on data generated by them.Even though PCR‐based methods become increasingly more widespread it is likely that most diagnostic methods will continue to be used or co‐exist in some form in the future.
Black Spot of Globe Artichoke: a Calcium‐deficiency Disorder
Authors: Morzadec J. M. , Hourmant A. , Corre J. , Romancer M. Le , Cottignies A. , Migliori A. 
Published: May 2008

AbstractExperiments were performed with field‐grown artichoke (Cynara scolymus L.) cv. Capitan to determine whether the black spot disorder was associated with calcium deficiency in receptacles. Ageing of the plants and size of heads contributed to lower Ca levels of receptacles. Receptacles with lower amounts of Ca were more affected by the disorder. Globe artichoke infection by artichoke latent virus (ALV) and/or broad bean wilt virus strain french artichoke (BBWV‐FA) resulted in decreases in both the relative water content (RWC) of leaves and the Ca content of receptacles, and in increased black spot incidence. In addition, a wind‐screen and an anti‐trans‐pirant spray (composed of a wax emulsion and a spreader/sticker surfactant) increased the RWC of leaves and bracts and the Ca content of receptacles, and also significantly reduced the incidence of necrosed buds.These data support the view that Ca deficiency is involved in the occurrence of black spot disorder.
Studies on Fusarium‐Gladiolus Interactions
Authors: Straathof TH. P. , Roebroeck E. J. A. , Löffler H. J. M. 
Published: May 2008

AbstractUsing standardized conditions, 65 genotypes of Gladiolus were screened for Fusarium resistance. High levels were found in ‘large‐flowered” types, Primulinus hybrids, G. callianthus, G. garnierii, and G. dalenii. Some accessions of G. dalenii exhibited no disease symptoms when inoculated with two standard test isolates. No resistance was found in ‘small‐flowered’ types. To estimate race‐specifity of the resistance, eight highly resistant Gladiolus genotypes were tested in an in vitro test against 43 isolates of F. oxysporum f.sp. gladioli. Two isolates were able to partially infect the G. dalenii accessions and this was confirmed using whole plants. Implications for resistance breeding are discussed.
Preservation of Purified Peanut Stripe and Turnip Mosaic Potyviruses by Freezing and Freeze‐drying
Authors: Fukumoto F. , Tochihara H. 
Published: May 2008

AbstractDuring storage at ‐ 20 °C of purified preparations of peanut stripe and turnip mosaic potyviruses, infectivity of intact particles and RNA extracted from preserved preparations decreased. This decrease can be attributed to several factors such as virus aggregation and alterations of the nucleic acids and coat proteins. However, the addition to the preparations of 0.5% peptone or 1% sucrose permitted a high level of infectivity to be retained for extended periods. Freeze‐drying led to aggregation of the particles and in a marked decrease of infectivity. Virus aggregatioti and RNA degradation were suppressed by the addition of protectants such as 0.5% lysine. Results suggest that other potyviruses may be well preserved under similar conditions.
Use of Heteroduplex Mobility Analysis (HMA) for Differentiating Phytoplasma Isolates Causing Witches’ Broom Disease on Populus nigra cv Italica and Stolbur or Big Bud Symptoms on Tomato
Authors: Cousin M‐T. , Roux J. , Boudon‐Padieu E. , Berges R. , Seemuller E. , Hiruki C. 
Published: May 2008

AbstractHeteroduplex mobility analysis (HMA) was performed to distinguish French and German isolates of phytoplasmas from Populus nigra cv Italica witches broom. The French isolate was similar to the phytoplasma responsible for the European aster yellows while the German isolate was different but closely related to it. When phytoplasmas inducing similar “stolbur” symptoms in tomato were compared to HMA, a high degree of genetic differences was observed among the reference stolbur C (StC) isolate, the European aster yellows and the other phytoplasmas inducing stolbur or big bud symptoms in tomato. Pseudo‐stolbur B and D from Brazil were differentiated from the reference St C using this method.
PCR‐Based Detection of Artificial Latent Infections of Geranium by Xanthomonas campestris pv. pelargonii
Authors: Sulzlnski M. A. , Schlagnhaufer B. , Moorman G.W. , Romaine C.P. 
Published: May 2008

AbstractA procedure entailing biological enrichment and PCR amplification was developed to detect small populations of Xanthomonas campestris pv. pelargonii (X.c, pv. pelargonii) in tissues of geranium. Known numbers of colony forming units (CFU) of X.c. pv. pelargonii were introduced into ‘Red Elite’ geraniums through wounding of petioles and stems. Immediately after inoculation, sections of the petioles and stems were harvested and incubated for 24 or 48 h in nutrient broth (biological enrichment). After enrichment, bacterial cells were collected by centrifugation, followed by rapid extraction of total nucleic acid from the cells with GeneReleaser™, PCR amplification of DNA with pathovar‐specific primers, and ethidium bromide‐stained agarose gel electrophoretic analysis of the PCR products. After 48 h biological enrichment, it was possible to detect as few as 1 CFU of Xc. pv. pelargonii in stems and petioles collected immediately after inoculation, with the detection limit ranging between 1 and 120 CFU during multiple experiments. It also was possible to detect systemic movement of the bacterium in intact plants sampled 24 h after inoculation with a minimal inoculum (4 CFU). This procedure may have application in geranium certification programs concerned with the detection of latent infections associated with low levels of X.c.pv. pelargonii.
The Use of Detached Seedling Leaves of Triticum aestivum to Study Pathogenicity in Puccinia recondita f. sp. tritici
Authors: Felsenstein F. G. , Park R. F. , Zeller F. J. 
Published: May 2008

AbstractA method is described for establishing isolates of Puccinia recondita f. sp. tritici (causal agent of brown rust of wheat) on detached seedling leaf segments. The method was used to compare the responses of leaf segments and intact seedling leaves for 28 differential genotypes inoculated with eight rust isolates. Leaf segments were incubated at two post‐inoculation temperatures (17 and 23C) and intact seedlings at 20–25 C. Reliable determinations of isolate pathogenicity was obtained using detached leaf segments of wheats with genes Lr l. Lr2a, Lr3a, Lr3bg., Lr3ka, Lr9, Lr15, Lrl9. Lr20, Lr24, Lr25. Lr26, Lr28, and Lr30 at both post‐inoculation temperatures, and for wheats with genes Lr2b. Lr2c, Lrl7, Lr23, Lr27 + Lr31 and LrH, at 23°C. Differences between leaf segments and intact leaves for the remaining eight differentials were attributed to inconsistent or poor expression of genes in detached leaf segments. By repeating tests with detached leaf segments, it was possible to establish the pathogenicities of the isolates on all of these differentials except those carrying Lr13, Lr14a, Lr16 and Lr18. Potential uses and limitations of the technique in studies of Puccinia recondita f. sp. tritici are discussed.
The Interaction of Humidity and Resistance Elicitors on Expression of Polygenic Resistance of Barley to Mildew
Authors: Newton A. C. , Dashwood E. P. 
Published: May 2008

AbstractElicitor‐active glucan was applied to leaves of genotypes of barley expressing different levels of resistance to powdery mildew (Erysiphe graminis f. sp. hordei)which was assessed by measuring mildew colonies per leaf or speed of papilla induction response to mildew challenge. The influence of humidity was also assessed by treating leaves with glucan, inoculating with mildew and immediately sealing the leaves in Perspex containers in an apparatus which enabled temperature, air speed and humidity to be controlled accurately. In water‐treated controls low humidity alone reduced colonies per leaf, and at 60% r.h. genotype 7204 showed significantly less effect of humidity compared with other genotypes, although at 40% it responded as other genotypes. At low humidity glucan stimulated resistance for genotypes Proctor and 7204 but not for Golden Promise or 9855; the effect of humidity or elicitor alone was only significant on genotype 7204, Chitin also proved an effective elicitor, but at high and not at low humidity. Time of pre‐treatment before mildew challenge, leaf stage, type of elicitor, concentration of elicitor, post‐inoculation light regime, mildew isolate and barley genotype all had major influences on papilla response. Other factors were less important. Based on papilla formation, the barley cultivar Proctor was most and Golden Promise the least responsive to glucan as an elicitor. The potential for exploiting the genetic basis of inducible resistance is discussed.
Surface‐related Changes of Fusing Phytophthora Zoospores
Authors: Ersek T. , English J. T. 
Published: May 2008

AbstractZoospores of Phytophthora spp. were fused and then regenerated using a technique previously described. At various points in the fusion and regeneration processes, components of spore surfaces were immunolabelled with specific monoclonal antibodies. Changes in the antigenic properties of spore surfaces during these events were monitored by fluorescence microscopy. Additional, surface‐related processes of the phenomena were monitored by electron microscopy, in the presence of lithium ions and polyethylene glycol, zoospores aggregated into clumps and began to fuse. During this time, zoospores retained their reniform shape and antibodies reacted only with plasma membrane‐bound antigenic components that are characteristic of the zoosporic state. Immuno‐labelling of cell wall occurred only after the fusion solution was replaced with a regeneration solution. As expected, the fusion and the asynchronous regeneration process resulted in the formation of enlarged cells with enlarged or multiple nuclei.
Pathogenicity, Non‐Host Hypersensitivity and Host Defence Non‐Permissibility Regulatory Gene hrpX is Highly Conserved in Xanthomonas Pathovars
Authors: Oku T. , Wakasaki Y. , Adachi N. , Kado C. I. , Tsuchiya K. , Hibi T. 
Published: May 2008

Abstract Xanthomonas campestris pv. campestris and X. oryzae pv, oryzae contain the 1428 base pair hrpX gene whose product is involved in the regulation oi hrp genes required for pathogericity, non‐host hypersensitivity and non‐permissibility of compatible host defence responses. Previous Southern blot hybridization studies have suggested that hrpX is conserved in several X. campestris pathovars and X. oryzae. strains. We have confirmed and extended these findings using hrpX gene amplification by polymerase chain reaction, coupled with Southern blot hybridization analyses. Sixteen distinct pathovars of X. campestris and 12 strains of X. oryzae pv, oryzae were shown to contain homologs of hrpX which were not apparent in heterologous bacteria such as Agrobacterium tumefaciens, A. rhizogenes, Erwinia carolovora ssp. carotovora, Pseudomonas syringae pv, glycinea. P. syringae pv, labaci, and Escherichia coli. The hrpX gene is therefore highly conserved among Xanthomonas species and its gene product strongly resembles positive regulatory proteins of the AraC protein family,
A UK Isolate of Impatiens Necrotic Spot Virus From Glasshouse‐grown Cineraria
Authors: Weekes R. J. , Barker I. , Spence N. J. , O'Neill T. , Wood K. R. 
Published: May 2008

AbstractA tospovirus was detected by ELISA in a Cineraria sample from a commercial protected crop in the UK. Its seroiogical properties indicated it to be Impatiens necrotic spot virus (INSV), results confirmed by RT‐PCR tests and nucleotide sequence data on the nucleoprotein‐encoding region of the genome. This is the first report of the presence of INSV in a protected crop grown in the UK.