bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural Studies on the Colonization of Banana Tissue and Fusarium oxysporum f. sp. cubense Race 4 by the Endophytic Bacterium Burkholderia cepacia
Authors: Pan M. J. , Rademan S. , Kunert K. , Hastings J. W. 
Published: May 2008

AbstractColonization on banana roots and on the pathogenic fungus, Fusarium oxysporum f. sp. cubense race 4, causing banana wilt disease, by the endophyte Burkholderia cepacia isolated from asparagus, which might be used as a biological control agent, was investigated with the aid of scanning and transmission electron microscopy. B. cepacia was able to colonize the surface of hyphae of F. oxysporum f. sp. cubense and the fungal macrospores. In vitro colonization ofthe fungus by the endophyte resulted in mycelial deformation with terminal and intercalary swelling. In the banana plant B. cepacia was closely associated with banana roots. A matrix was frequently found to be present between the bacterium and the plant surface. Transmission electron microscopy observations showed that B. cepacia exists mainly in the intercellular space of the banana root tissues.
Les Phénolamides des Rachis de Palmes, Composants de la Réaction de Défense du Palmier Dattier vis‐à‐vis de Fusarium oxysporum f.sp. albedinis, Agent Causal du Bayoud
Authors: Ramos T. , Bellaj M. EL , Idrissi‐Tourane A. EL , Daayf F. , Hadrami I. EL 
Published: May 2008

Abstract Phenolamides in the Rachis of Palms: Components of the Defence Reaction of the Date‐palm towards Fusarium oxysporum f.sp. albedinis, the Causal agent of ‘Bayoud’ This is the first study showing evidence of the production of phenolic and phenolamidic compounds in date palm tissues in response to attack by Fusarium oxysporum f.sp. albedinis (Foa), the causal agent of the wilt called bayoud. Marked quantitative and qualitative differences were recorded in the production of such compounds when infected and healthy rachis, were compared. In addition, localized accumulation of some compounds was detected when infected and healthy parts of the same rachis were analysed. Three induced hydroxycinnamoylamides were detected in high concentrations. They were isolated and tested for their toxicity against Foa. These compounds were shown to strongly inhibit conidial germination and germ tube growth of the pathogen and must be considered as phytoalexins. The role of amides in the date palm resistance to the bayoud is discussed.
Induced Resistance in Pepper Leaves Infiltrated with Purified Bacterial Elicitors from Xanthomonas campestris pv. vesicatoria
Authors: Romeiro R. S. , Kimura O. 
Published: May 2008

AbstractCell components (lipopolysaccharide (LPS), exopolysaccharide (EPS), capsular glycoproteins and the cell envelope) were extracted and purified from cells of compatible and incompatible isolates of Xanthomonas campestris pv. vesicatoria and infiltrated into pepper leaves in an attempt to protect them against a compatible isolate. All cell components induced protection but only EPS and the cell envelope elicited phytoalexins. Therefore, resistance mechanisms other than phytoalexins may exist in pepper leaves and appear to be more effective than phytoalexins.
Detection of Polymorphism in Puccinia hordei using RFLP and RAPD Markers, Differential Cultivars, and Analysis of the Intergenic Spacer Region of rDNA
Authors: Jennings J. M. , Newton A. C. , Buck K. W. 
Published: May 2008

AbstractA world‐wide range of isolates of Pucinia hordei and P. striformis f. sp. hordei and UK isolates of P. striformis f. sp. tritici and P. recondita were characterized using DNA restriction fragment length polymorphisms (RFLPs), random amplified polymorphic DNAs (RAPDs), ribosomal DNA (rDNA) intergenic sequence(IGS) or virulence on differential cultivars. The different species were readily distinguished by both RFLPs and RAPDs. Within a species, variability was detected using differential cultivars, RAPDs, and RFLPs with probes from the rDNA region, indicating their potential for population analysis. However, RFLPs within a species were not detected using a wide range of random (anonymous) probes from a P. hordei genomic library. Previous assumptions about the general uniformity of rust genotypes were reassessed from these data.
Cytopathology of Developing Anthers and Pollen Mother Cells from Lettuce Plants Infected by Lettuce Mosaic Potyvirus
Authors: Hunter D. G. , Bowyer J. W. 
Published: May 2008

AbstractUltrastructural studies of developing anthers from young flowers of lettuce (Lactuca saliva L.) infected with lettuce mosaic potyvirus (LMV) revealed infection in the pollen mother cells of one of three plat. Within the infected pollen mother cells, structures reminiscent of bundles and partly formed pinwheel inclusions were observed, Immunogold labelling showed that particles of LMV were associated with these structures. Neither large aggregates of LMV particles nor complete pinwheel inclusions were observed in pollen mother cells. Infection of pollen mother cells was consistently correlated with infection of the adjacent tapetal cell layer. Pollen mother cells of two other LMV‐infected plants were not infected. This study supports the hypothesis that early invasion of the floral meristem is necessary for virus infection of mature pollen grains.
Involvement of Toxins Produced by Pseudomonas fuscovaginae in Aetiology of Rice Bacterial Sheath Brown Rot
Authors: Batoko H. , Bouharmont J. , Kinet J.‐M. , Marite H. 
Published: May 2008

AbstractThe incidence of bacterial sheath brown rot of rice was assessed throughout the whole cycle of rice plat cultivation after seedling inoculation, under greenhouse conditions. Typical symptoms of the disease were expressed at the booting. The degree of disease susceptibility could be determined after heading by monitoring panicle emergence rate of diseased plants. Inoculation at the booting stage showed that tolerance could be associated with reduced bacterial growth 4 days after inoculation. Rice plants were sensitive to purified bacterial toxin at all growth stages. The toxins reproduced symptoms observed on diseased plants. In particular, poor panicle emergence, due to inhibition of culm elongation during heading, could be clearly attributed to the detrimental effects of the toxins. For the cultivars investigated in this study, the severity of the toxin damage was related to the degree of cultivar susceptibility to the pathogen, although the phytotoxins are non‐host‐specific. These phytotoxins can therefore be considered as integral part of the plant pathogen‐interaction.
Phenolic Compounds of Apple and their Relationship to Scab Resistance
Authors: Mayr U. , Michalek S. , Treutter D. , Feucht W. 
Published: May 2008

AbstractThe contents of 15 different phenolic compounds in apple leaves and fruit skin from various orchards were determined by HPLC. High concentrations of flavan‐3‐ols were found in those orchards which were not infected by Venturia inaequalis. This observation corroborates earlier findings on different cultivars. The hypothesis that these compounds could be involved in the resistance of apple to scab was tested by inhibiting the key enzyme of the phenol biosynthesis, the phenylalanine‐ammonia‐lyase, in young shoots of the resistant genotype ‘Sir Prize'. After inoculation of the inhibitor‐treated leaves, severe symptoms of the disease occurred. The fungal infection was confirmed by histological studies. No flavonal‐accumulation could be observed at the infection site which was the case in the non‐inhibited but inoculated controls.
Somatic Embryogenesis from Style Culture as a Possible Means for Virus Elimination in Citrus
Authors: D'Onghia A.M. , de Pasquale F. , Carimi F. , Savino V. , Crescimanno F.G. 
Published: May 2008

AbstractSomatic embryos were obtained from stylar tissues of three lemon plants, one of cv Lunario, one of Femminello Zagara Bianca, and one of Femminello Santa Teresa. These plants, as shown by visual observations and indexing on woody indicators, were affected by exocortis and two or more virus‐like diseases such as psorosis, concave gum, impietratura and cristacortis. Two of the sources contained also mechanically transmissible viruses. Twelve 18‐month‐old plantlets originating from style culture‐derived somatic embryos, four from each source, consistently gave negative reactions when assayed by grafting, mechanical inoculation, and serologically for the presence of viruses, virus‐like agents and viroids. It was concluded that, similar to other woody species (e.g. grapevine), somatic embryogenesis opens new possibilities for the sanitary improvement of Citrus.
RAPD‐based Molecular Diagnosis of Mixed Fungal Infections on Oilseed Rape (Brassica napus): Evidence for Genus‐ and Species‐specific Sequences in the Fungal Genomes
Authors: Schleier S. , Voigt K. , Wostemeyer J. 
Published: May 2008

AbstractOilseed rape (Brassica napus) is attacked by many parasitic fungi which often occur in mixed infections. Monitoring of these phytopathogens by morphological criteria is restricted due to their appearance especially in the later stages of disease development.We have developed molecular markers for a clear‐cut differentiation of a variety of rape seed pathogenic fungi based on randomly amplified polymorphic DNA (RAPD). Twenty polymorphic fragments have been selected in Southern hybridization experiments to test their taxon‐specificity. In summary, only four amplification products gave unspecific cross‐hybridization patterns, one fragment corresponds to a genetic element common to three species within the genus Alternaria, and 15 RAPD markers were highly specific for distinct fungal species. This report demonstrates the value of the RAPDPCR technique to amplify taxon‐specific DNA fragments that can be used as hybridization probes for the diagnosis of a variety of rape seed pathogens (Alternaria brassicae, A. brassicicola, A. raphani: Cylindrosporium concentricum; Fusarium moniliforme; Phoma lingam; Pythium sp.; Rhizoctonia solani, Sclerotinia sclerotiorum; Verticillium dahliae, V. latericium).
The Potential for Pollen‐borne Virus Transfer in a Plum Orchard Infected With Prunus Necrotic Ringspot Virus
Authors: Milne J. R. , Walter G. H. 
Published: May 2008

Abstract Prunus necrotic ringspot virus (PNRSV) is borne in stonefruit pollen. Previous work has shown that virus particles can enter cucumber seedlings when virus‐bearing pollen grains contact puncture holes made in plant cells by thrips feeding. Stonefruit plant parts on which pollen is deposited and thrips spend considerable time feeding, are likely sites of PNRSV inoculation. The principal agents of pollen deposition may therefore play a key role in PNRSV epidemiology. We determined the principal sites of pollen deposition on Japanese plum trees and the major pollen depositing agents in a PNRSV‐infected orchard in southeastern Queensland. Plum pollen was deposited mostly onto flowers, with few grains being found on leaves or stems. Within the flowers, pollen grains were distributed mostly on the petals, but some were found on the sepals, filaments and carpels. Honey bees were the most frequent visitors to plum flowers and they deposited more than any other insects. Flies visited flowers at low frequencies and also deposited pollen. Significant amounts of pollen were deposited onto flowers by unidentified nocturnal agents. Thrips were not observed during the study period, although they were present in the orchard. Previous studies have assumed that thrips carry virus‐bearing pollen as well as bring it into proximity of feeding wounds. Our results suggest that, although thrips carriage of pollen may occur, it is not necessary for PNRSV spread in stonefruit orchards.
Deoxynivalenol and Acetyldeoxynivalenol Accumulation in Field Maize Inoculated with Fusarium graminearum
Authors: Perkowski J. , Proñczuk M. , Chelkowski J. 
Published: May 2008

AbstractSeven selected maize hybrids (Smolimag, Ruten, KLG 2210, Zenit, Betulisa, RAH BE 86101 and RAH BE 90102) were toothpick inoculated in the ear (at ∼ 10 days after midsilk) with a single isolate of Fusarium graminearum in order to determine their reaction to infection and susceptibility to mycotoxin accumulation in the tissues. Deoxynivalenol (DON), 15‐acetyldeoxynivalenol (15‐AcDON), and 3‐acetyldeoxynivalenol (3‐AcDON) were detected in differing amounts in kernels, husks, stalks (nodes and internodes) and roots. DON was recovered from stems, husks and damaged kernels at levels of 864, 278 and 93mg/kg, respectively, while 15‐AcDON was recovered at 235, 55 and 11mg/kg and 3‐AcDON was recovered at 3, 2 and 0.5 mg/kg, respectively. Maize hybrids Smolimag and Ruten were most resistant to infection and contained the lowest amounts of mycotoxins in the tissues while Zenit, RAH BE 90102, RAH BE 86101 and Betulisa were most susceptible to infection and accumulated higher amounts of mycotoxins.
Investigations on the Activity of Cell Wall‐degrading Enzymes in Young Wheat Plants After Infection with Pseudocercosporella herpotrichoides (From) Deighton
Authors: Mbwaga A. M. , Menke G. , Grossmann F. 
Published: May 2008

AbstractIn earlier investigations, it has been demonstrated that Pseudocercosporella herpotrichoides (Fron) Deighton is capable of producing pectolytic and cellulolytic enzymes as well as hemicellulases in vitro. The investigation of enzyme activity in extracts from wheat plants infected with P. herpotrichoides (isolates 21e and R6) and from non‐infected plants revealed the activity of the following enzymes: pectin methylesterase (PME), polymethylgalacturonase (PMG), pectin lyase (PL), carboxymethylcellulase (CMCase), xylanase and arabanase. Compared to non‐infected plants, the enzyme activity in infected plants was considerably higher; in some experiments, only traces of enzyme activity could be found in control plants. The difference in the enzyme activity in infected as compared to non‐infected plants was, in most cases, statistically significant, especially beginning at the end of the second week after inoculation.The enzyme activity depended on the temperature during plant cultivation; with the exception of pectin methylesterase (PME), the activity of all investigated enzymes increased with temperature and the highest activity was found in plants grown at 20°C. The highest PME activity was measured in plants grown at 10°C; the activity of this enzyme was generally lower at 15 and 20°C.
Distribution of Antagonistic Streptomyces griseoviridis in Rhizosphere and Nonrhizosphere Sand
Authors: Kortemaa H. , Pennanen T. , Smolander A. , Haahtela K. 
Published: May 2008

AbstractThe ability of Streptomyces griseoviridis to colonize roots was studied on turnip rape (Brassica rapa ssp. oleifera) and carrot (Daucus carota) using the sand‐tube method. The biofungicide Mycostop or a spore suspension of S. griseoviridis was mixed in sterile and in non‐sterile sand. Population densities of the antagonist in the rhizosphere were significantly higher than in non‐rhizosphere and in root‐free sand. There was no significant difference between the plant species and root depths on distrubution of the antagonist. Higher rates of detection were achieved when root segments were placed on petri plates of agar than when homogenized and subsequently dilution plated. Homogenization of sand samples increased the detected population densities of S. griseoviridis. Muramic acid assay with HPLC indicated higher densities in the rhizosphere compared with non‐rhizosphere and rootfree sand. Distribution of S. griseoviridis in the rhizosphere was observed using scanning electron microscopy. The antagonist produced high spore densities in the root‐hair zone of turnip rape. S. griseoviridis mixed in sterile and non‐sterile sand survives in the rhizosphere, non‐rhizosphere and root‐free sand where it probably exists both as spores and mycelia.
Endo‐ and Exochitinase Activity in Kiwifruit Infected with Botrytis cinerea
Authors: Wurms K. , Long P. , Greenwood D. , Sharrock K. , Ganesh S. 
Published: May 2008

AbstractEndo‐ and exochitinase activities were determined in autoclaved leaves, live leaves, and fruit of kiwifruit (Actinidia deliciosa var. deliciosa cv. Hayward [A. Chev.]Liang and Ferguson) following infection with Botrytis cinerea (Pers.). Appreciable endochitinase activity was found in healthy and diseased leaves and fruit at harvest and after cool‐storage, but was absent in plant tissue killed by autoclaving. Later harvested fruit produced more endochitinase activity in storage than did early harvested fruit. Exochitinase activity was only associated with diseased tissue, and was present in diseased autoclaved leaves. The results suggest that endochitinase activity originates from the plant whilst exochitinase is associated with the pathogen. The significance of these findings is discussed.
Induced Resistance to Erwinia carotovora ssp. atroseptica, Through the Treatment of Surface Wounds of Potato Tubers with Elicitors
Authors: Dutton M. V. , Rigby N. M. , Macdougall A. J. 
Published: May 2008

AbstractWe have investigated the ability of mixed oligogalacturonides, a cell wall hydrolysate from Phytophthora sojae Hildebrand, and chitosan oligomers to induce resistance to Erwinia carotovora ssp. atroseptica in potato tubers (cv. Pentland Squire). Natural infection by Erwinia in stored potatoes generally originates in the surface tissues which have a markedly different biochemical composition to the perimedullary tissue. We therefore investigated the effect of different elicitors in inducing resistance in 2 mm deep wounds made on the surface of potato tubers. When wounded in this way and stored at 20°C and 100% relative humidity, tubers developed a significant level of natural resistance within 24 h. When the potatoes were treated with oligogalacturonides, or Phytophthora cell wall hydrolysate at the time of wounding and challenged with inoculum 8 h later, a significant reduction in disease occurred. Treatment with the chitosan elicitor had no effect on resistance.
Germination and Infectious Potential of Microconidia of Sclerotium cepivorum
Authors: Gindro C. , L'Hoste G. 
Published: May 2008

AbstractObservation with the scanning electron microscope showed that microconidia of Sclerotium cepivorum are able to germinate on onion plants. A young hypha penetrated the plant cuticle. Cytochemical techniques gave evidence of phenoloxydase and esterase activities in microconidia and thus confirmed their infectious potential. Massive production of microconidia was induced by immersion of the fungus in water.These elements suggest that in high moisture conditions microconidia of S. cepivorum might play a crucial role in survival and dissemination of the fungus.
A Simple DNA Extraction Method for PCR‐based Detection of Xanthomonas campestris pv. pelargonii in Geraniums
Authors: Sulzinski M. A. , Moorman G. W. , Schlagnhaufer B. , Romaine C. P. 
Published: May 2008

AbstractA simple method for PCR‐based plant clinical diagnosis of bacterial blight of geraniums caused by Xanthomonas campestris pv. pelargonii is described. The method entails maceration of infected tissues in water or 10mM Tris‐ HCI, pH 8.0 buffer, followed by treatment of the macerate with a commercially‐available extraction matrix (GeneReleaserTM) in which nucleic acid is released by brief microwave heating. Nucleic acid prepared in this manner served directly as template for PCR amplification with primers targeting a sequence in the genome of the bacterium. Using this protocol, it was possible to quickly identify X. campestris pv. pelargonii in infected geraniums, whereas amplification products were not obtained with nucleic acid preparations from noninfected plants, or from plants infected with the bacterial pathogens, Corynebacterium fascians or Pseudomonas cichorii.
Infectivity of Chlamydospores vs Microconidia of Fusarium oxysporum f.sp. lycopersici on Tomato
Authors: De Cal A. , Pascual S. , Melgarejo P. 
Published: May 2008

AbstractThe effect of nature of inoculum on disease induced by Fusarium oxysporum f.sp. lycopersici on tomato was tested. Chlamydospores produced in soil 30 days after inoculation induced a more severe disease than microconidia indicating a higher inoculum potential of chlamydospores.The method proposed produces easily an inoculum of F. oxysporum f.sp. lycopersici which infects the plants consistently and induces a relatively high disease severity.
Use of the Reverse Transcription‐Polymerase Chain Reaction for the Detection of Pelargonium Flower Break Carmovirus
Authors: Franck A. , Loebenstein G. , Gera A. 
Published: May 2008

AbstractA polymerase chain reaction (PCR)‐based assay was used to detect pelargonium flower break carmovirus (PFBV) in total RNA extractions made from infected Pelargonium plants. Extracts were reverse transcribed (RT) and the resultant cDNA was amplified by PCR, using oligonucleotide primers specific for 343, 510 and 832 base pair fragments of the RNA‐dependent RNA polymerase gene of PFBV.The specificity and sensitivity of RT‐PCR were compared with the enzyme‐linked immunosorbent assay (ELISA) for the detection of PFBV in Pelargonium tissues. The virus could be detected efficiently in high dilutions of sap from infected plants and at low concentrations of purified virus. Although ELISA is a powerful tool for virus detection, RT‐PCR was over 1000 times more sensitive in detecting PFBV in leaf extracts of infected Pelargonium than was ELISA. The limit of detecting PFBV RNA by RT‐PCR was 200 fg, compared with 200 pg of virus by ELISA.
Cytopathological Responses of Picea abies Seedling Roots Challenged in vitro by a Necrotrophic Fusarium avenaceum (Fr.) Sacc.
Authors: Asiegbu F. O. , Johansson M. , Daniel G. 
Published: May 2008

AbstractInteraction of the necrotroph Fusarium avenaceum with seedling roots of Norway spruce was studied. The results showed that Norway spruce seedlings were susceptible to the pathogen but disease progression and severity was dependent on inoculum potential. Host recognition of the pathogen marked by hypersensitive browning reactions occurred late, thus making successful resistance to cellular damage impossible. Such host resistance responses were mostly in the form of lignification, accumulation of electron dense materials and papillae formation.
The Infection Court of Faba Bean Seedlings for Oospores of Peronospora viciae f.sp. fabae in Soil
Authors: van der Gaag D. J. , Frinking H. D. 
Published: May 2008

AbstractThe infection court of Faba bean seedlings for oospores of Peronospora viciae f.sp. fabae in soil was determined. Soil naturally infested with oospores was placed as 3‐cm thick layers at four different depths relative to Faba bean seeds. Seedlings with downy mildew were obtained only from seeds sown in the middle of a 3‐cm layer of oosporeinfested soil. No infection was obtained from oosporeinfested soil placed more than 1.5 cm above or below seeds. Histological observations showed that the hypocotyl and first part of the main root were the most probable sites of infection.
Bacterial Diseases on Witloof Chicory Crops in Europe
Authors: Balestra G. M. , Varvaro L. 
Published: May 2008

AbstractDistribution of principal phytopathogenic bacterial populations on witloof chicory crops in Europe is reported.Different symptoms caused by phytopathogenic bacterial populations on different parts of witloof chicory plants are described. The first report of Pseudomonas fluorescens (Trevisan) Migula and occurrence of Erwinia carotovora (Jones, 1901) bacterial populations on witloof chicory cv. Rosso di Chioggia crops in Italy (Latium region), are reported. Risks of disease during different phases of production of this crop and phytosanitary measures to reduce the incidence of disease caused by these pathogens are discussed.