bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occurrence of Phytoplasma Infection in European Plums (Prunus domestica)
Authors: Pollini C. Poggi , Bissani R. , Giunchedi L. , Vindimian E. 
Published: May 2008

AbstractPhytoplasmas were constantly detected by the DAPI technique and by PCR amplification of DNA from European plums (Prunus domestica) cv ‘Susina di Dro’ with symptoms similar to those reported for Japanese plum leptonecrosis. These symptoms included upward rolling of the leaves, which also became bronzed‐reddish, thick and brittle, growth of normally dormant axillary buds, off‐scason growth during November January and phloem necrosis. Trees with symptoms showed progressive decline. RFLP analysis, revealed that the phytoplasma isolated from the affected plum trees is closely related to the other phytoplasmas present in Prunus species in Europe and can be included in the apple proliferation cluster. Although Japanese plum leptonecrosis is common in Europe. this is the first report of a wide‐spread phytoplasma‐induced decline in a cultivar of European plum.
PMTV‐Like Particles Inside Resting Spores of Spongospora subterranea
Authors: Merz U. 
Published: May 2008

AbstractRod‐shaped particles were found in cysts of a Spongospora subterranea cystosorus after freeze‐fracturing with a mean diameter of 20.5 nm and a maximum length of 500 nm. Their possible identity is discussed.
Isolation and Characterization of a Pseudomonas fluorescens Strain Suppressive to Bipolaris maydis
Authors: Mohamed S. , Caunter I. G. 
Published: May 2008

AbstractStrain PJ0210, identified as Pseudomonas fluorescens, inhibited Bipolaris maydis both in vitro. The absence of detectable inhibitory substances assayed by a variety of methods indicated nutrient competition as the operative component of antagonism. This was further supported by observations of reduced inhibition by addition of glucose both in vitro and in vivo. Strain PJ0210 was adaptecd to the phyllosphere showing good survivability and colonizing ability both inplant house and field trials. Disease suppression was generally correlated with population sizes of strain PJ0210. Population sizes in the field were lower than those recorded in the plant house with a concomitant reduction in disease suppressive ability, of strain PJ0210.
Peroxidase Activity and Isoperoxidase Pattern in Tobacco Leaves Infected with Tobacco Necrosis Virus and Other Viruses Inducing Necrotic and Non‐Necrotic Alterations
Authors: Montalbini P. , Buonaurio R. , Kumar N. N. Umesh 
Published: May 2008

AbstractThe level of peroxidase activity was greatly enhanced in tobacco leaves infected by tobacco necrosis virus (TNV) and other viruses which induce necrotic symptoms (TMV, ToMV and PVYN). The intensity was related to the age of the leaves infected: absent or neglible in mature leaves and very pronounced in young growing infected leaves. On the contrary, changes in peroxidase activity were negligible when the infection was provoked by viruses which do not produce necrotic reactions (TMV and PVYO). Analysis of the peroxidase isoenzymes, pattern in tobacco leaves infected by TNV and other necrosis‐inducing viruses revealed in all cases, a slight increase in anionic (pl 3.5–3.7) and a considerable increase in moderately anionic isoenzymes particularly the pl 4.6 isoenzyme which in TNV and PVYN‐infected leaves reached levels up to 21 and 72 times the healthy control values. A considerable increase in the cationic (pl9.3–8.8) isoenzymes and the appearance of one moderately cationic isoenzyme (pl 8.2) was also detected. In leaf extracts from‐virus‐infected tobacco leaves with nonnecrotic response, no, or negligible alterations on the isoenzyme pattern were detected. However, infection by a fungal parasite (Erisyphe cichoracearum), which established a fully compatible, non‐necrotic, interaction with tobacco leaves, like the necrosis‐inducing viruses, changed the isoperoxidase pattern. The data suggest the necrotic alterations and associated changes in the peroxidase activity and isoperoxidase pattern in virus‐infected leaves are not clearly related.
A Monogenic Dominant Resistance of Tomato to Bacterial Wilt in Hawaii 7996 is Associated with Plant Colonization by Pseudomonas solanacearum
Authors: Grimault V. , Prior P. , Anaïs G. 
Published: May 2008

AbstractHawaii 7996, a tomato cultivar resistant to bacterial wilt caused by P. solanacearum was crossed with Floradel, a susceptible cultivar and the F1 and F2 seeds were obtained. Inoculated plants were tested in the field for bacterial wilt resistance and colonization by P. solanacearum. The F1 did not wilt and a significant 3:1 segregation for non wilting: wilting was observed in the F2, indicating a monogenic dominant resistance in Hawaii 7996. In the F2 and in Hawaii 7996, resistance was, associated to the limitation of bacterial spread in the stem. The degree of resistance of Floradel, the F2 and Hawaï 7996 was correlated to colonization at midstem. The usefulness of plant colonization criteria for breeding programs is discussed.
Polyploidy Among Isolates of Phytophthora infestans from Eastern Germany
Authors: Daggett S. S. , Knighton J. E. , Therrien C. D. 
Published: May 2008

AbstractThe ploidy of 101 isolates of Phytophihora infestans from the eastern states of the Federal Republic of Germany (formerly the German Democratic Republic) was determined by Feulgen DNA microdensitometry. The isolates used in this investigation were collected during 11 growing seasons between 1976 and 1990. Fifty hyphal nuclei per isolate were used for DNA measurements. Polyploids predominated throughout the 15‐year sampling period. Four of the isolates collected during 1989 were diploid. Based on the results of this investigation, there appears to have been no trend towards a diploid. sexual population during the sampling period.
The Influences of Epicuticular Wax Disruption and Cutinase Resistance on Penetration of Tomatoes by Colletotrichum gloeosporioides
Authors: Cruickshank R. H. 
Published: May 2008

AbstractConidia of Colletotrichum gloeosporioides germinated on green and ripe tomato fruit with intact epicuticular wax, and formed penetration pegs below melanized appressoria. If the delicate layer of epicuticular wax was distupted by abrasion or removed by solvents before inoculation, apparent increased diffusion of fruit substances into the inoculum stimulated fungal growth, hyphal anastomosis and the production of penetration pegs from hyaline appressoria. This was followed by cutlcle erosion centred on the penetration pegs in green fruit allowing sec‐ondary growth of infection hyphae. Due to the development of cutinase resistance when the cuticle became yellow at ripening, no cuticle erosion occurred at penetrations on ripe fruit Since cuticle erosion followed penetration of the cutinase‐susceptible cuticle and since penetration peg formation was not hindered by the cutinase cuticle, the process of primary penetration is regarded as mechanical.
The Natural Occurrence of Chickpea Chlorotic Dwarf Geminivirus in Chickpea and Faba Bean in the Sudan
Authors: Makkouk K. M. , Dafalla G. , Hussein M. , Kumari S. G. 
Published: May 2008

AbstractA survey of faba bean and chickpea for virus infection, conducted during February 1994 in the Sudan, showed that bean yellow mosaic potyvirus and broad bean mottle bromovirus occurred commonly in both crops. Chickpea chlorotic dwarf geminivirus (CCDV) was detected for the first time in naturally infected chickpeas and faba beans. This is the first report of natural CCDV infection of chickpeas outside India and the first record of chickpea and faba bean infection in West Asia and North Africa (WANA).
In vitro Antagonism of Phytophthora cinnamomi and P. citricola by Isolates of Trichoderma spp. and Gliocladium virens
Authors: Chambers S. M. , Scott E. S. 
Published: May 2008

AbstractThree fungi, isolated from soil from which Phytophthora was not obtained, were evaluated for antagonism of Phytophthora spp. shown to cause root rot of chestnut in South Australia. Trichoderma hamatum and T. pseudokoningii appeared to inhibit P. cinnamomi by mycoparasitism. with evidence of parallel growth and coiling, and both Trichoderma spp. and Gliocladium virens grew over P. cinnamomi in vitro, preventing further growth of this pathogen. Antibiotics produced by young T. hamatum cultures and G. virens in culture filtrate experiments inhibited growth of P. cinnamomi and P. citricola. with filtrate from 4‐day‐old cultures of G. virens showing the greatest potential for biocontrol. All three antagonists prevented P. cinnamomi and P. citricola from causing infection symptoms on micropropagated shoots of chestnut cvs Goldsworthy and Buffalo Queen in an in vitro excised shoot bioassay for biocontrol.
European Stone Fruit Yellows Phytoplasma as the Cause of Peach Vein Enlargement and other Yellows and Decline Diseases of Stone Fruits in Southern Italy
Authors: Marcone C. , Ragozzino A. , Seemüller E. 
Published: May 2008

AbstractIn the Campania region of southern Italy, peach trees showing vein enlargement and decline symptoms, as well as apricot and Japanese plum trees showing symptoms similar to that of apricot chlorotic leaf roll and plum leptonecrosis, respectively, were examined for phytoplasma infection using PCR technology. From diseased apricot and plum trees, the target DNA could be amplified with both universal phytoplasma primers and primers that are specific for fruit tree phytoplasmas of the apple proliferation group. However, from samples from diseased peach trees, detectable amplification products were only obtained by nested PCR, in which amplification with universal phytoplasma primers was followed by amplification with primers specific for the apple proliferation group. Following digestion of the amplification products with suitable restriction enzymes, all strains from apricot, plum, and peach showed the same restriction profiles that were identical to those of the European stone fruit yellows phytoplasma, a member of the apple proliferation group.
Alternaria alternata f. sp. helianthina: a New Pathotype of the Fungus Causing Alternaria Leaf Spot to Sunflower
Authors: Lagopodi A. L. , Thanassoulopoulos C. C. 
Published: May 2008

AbstractPathogenicity tests of Alternaria alternata pathogenic on sunflower were effected on various plants in order to determine the host range of the fungus. Twenty‐five plant species, including members of four botanical families of cultivated plants and seven families of weeds were tested in greenhouse experiments for susceptibility to the fungus by artificial inoculations. Among all plants tested sunflower was found to be the only species highly susceptible to this pathogen. To distinguish this A. alternata which attacks sunflower among other known formae speciales of the fungus we propose for it to be named as Alternaria alternata f. sp. helianthina f. sp. nova.
Barley Yellow Striate Mosaic Rhabdovirus Naturally Infects Cereal Crops in the Anatolian Plateau of Turkey
Authors: Makkouk K. M. , Bertschinger L. , Conti M. , Bolay N. , Dusunceli F. 
Published: May 2008

AbstractField surveys of cereal crops in the Anatolian Plateau of Turkey revealed that bread wheat, durum wheat, barley, triticale and oats are naturally itifected with barley yellow striate mosaic rhabdovirus. Identification was based on symptomatology, double antibody sandwich ELISA (DAS‐ELISA), tissue‐blot immunoassay (TBIA) and immunoelectron microscopy (IEM). BYSMV was identified in cereal fields near Ankara, Eskisehir, Konya, Karaman and in an area 70km north east of Isparta. Virus incidence in all the fields surveyed was less than 1%. This is the first report where evidence is presented on the natural occurrence of BYSMV on cereals in Turkey.
The Probability of Detecting Clavibacter michiganensis subsp. sepedonicus by Indexing Seed Potato Lots with Serological Tests
Authors: De Boer S. H. , Hall J. W. 
Published: May 2008

AbstractDetection of the bacterial ring pot pathogen (Clavibacter michiganensis subsp. spedonicus) in seed potato lots by laboratory indexing complements visual inspection. The probability of detecting symptomless infections is a function of sample size and incidence of infection. We determined the incidence of asymptomatic stem and tuber infections in four potato cultivars at three levels of inoculum. At the high inoculum level, 51–93% of stems were infected at 80 days after planting, and 10–59% of the tubers were infected at harvest. The effect of the different percentages of infected stems and tubers on the probability of detection for simple random sampling was calculated for a constant sample size. The actual detection levels for two cultivars planted in field plots with predetermined incidence levels of ring rot infected plants were reasonably close to predicted probabilities.
The Spread of Epiphytic Populations of Xanthomonas campestris pv. vesicatoria on Pepper in the Field
Authors: Bernal R. F. , Berger R. D. 
Published: May 2008

AbstractThe spread of the epiphytic population of Xanthomonas campestris pv. vesicatoria and the disease it causes, bacterial leaf spot, were studied in field plots of pepper near Gainesville, Florida. In the summer of 1989, the epiphytic population of X. campestris pv. vesicatoria was dispersed to the west‐northwest from point sources of diseased plants. Winds from the southeast during rainstorms were essential for the spread of bacteria in the field. In the autumn of 1989, a focus of bacterial leaf spot developed naturally near the centre of the experimental plot. The epiphytic population of X, campestris pv. vesicatoria increased sharply after a 2‐day rain accompanied with strong wind. The wind was believed to be responsible for the transport of bacteria to distances 32 m from the focus. Initially in both seasons, the epiphytic populations occurred as distinct gradients from the focal sources of diseased plants. These gradients flattened over time and the disease incidence increased to near 100%, The increase in the epiphytic populations of the pathogen to > 3.0 log10 (cfu cm−2) on healthy plants away from the foci preceded disease appearance by several weeks. Applications of cupric hydroxide plus mancozeb significantly reduced the epiphytic population of X. campestris pv. vesicatoria on pepper leaves and slowed the spread of disease in the plots.
Location of the 5′ Termini of Tobacco Necrosis Virus Strain D Subgenomic mRNAs
Authors: Offel S. K. , Coutts R. H. A. 
Published: May 2008

AbstractNorthern blot analysis of double‐stranded (ds) RNA from bean‐leaf tissue infected with tobacco necrosis virus strain D (TNV‐D) detected the 4 kb genomic RNA and two subgenomic RNAs of about 1.5 kb and 1.2 kb; RNA extracted from virus particles only contained the genomic species. Blotting and probing with a range of probes indicated the approximate locations of the 5’ends of subgenomic RNA so that primers to fine‐map the ends could be designed. When both singlestranded and ds RNA, extracted from TNV‐D infected and healthy bean leaves were used as templates for primer extension using primers complementary to sequences at, or upstream of, the initiation codons of, respectively, the coat protein and the p7a genes, major infectionspecific products were detected. Both subgenomic RNAs start at G residues. The larger subgenomic RNA is 1547 nucleotides in length with a leader sequences of 36 nucleotides upstream of the p7a gene, and the smaller subgenomic RNA has a 90 nucleotide leader upstream of the coat protein AUG and is 1202 nucteotides long. An analysis of the 5’terminal locations of both subgenomic RNAs and the previously mapped analogous subgenomic RNAs associated with infection with the related TNV‐A isolate, revealed a marked degree of homology downstream of the initiation sites for each RNA. This homology was maintained at the 5’termini of both virion RNAs and could be extended to another isolate of TNV for which partial sequence data, but not subgenomic mapping RNA data are available.
The Natural Occurrence of Eggplant Mottled Dwarf Rhabdovirus in Tobacco in Italy
Authors: Polverari A. , Marte M. , Castellano M. A. 
Published: May 2008

AbstractThe natural occurrence of eggplant mottled dwarf rhabdovirus (EMDV) in field‐grown tobacco plants iti Italy is reported. The virus was identified by the differential reactions of herbaceous hosts, electron microscopy and serology. This seems to be the first record of natural itifection of tobacco by EMDV.
Characterization of Xanthomonas campestris pv. pruni strains from different hosts by pathogenicity tests and analysis of whole‐cell fatty acids and whole‐cell proteins
Authors: Scortichini M. , Janse J. D. , Rossi M. P. , Derks J. H. J. 
Published: May 2008

AbstractStrains of Xanthomonas campestris pv. pruni obtained from Prunus armeniaca. P. domestica, P. persica and P. salicina in different geographical areas were compared for pathogenicity, fatty acid and wholecell protein analysis. Four strains, one per each host plant, were inoculated at the same time, on the foliage of P. armeniaca, P. avium, P. persica and P. salicina cultivars. Mean content of fatty acids of X.c. pv. pruni strains were also compared with those of many strains of X.c. pv. campestris, pv. graminis, pv. hyacinthii, pv. pelargonii and pv. vasculorum. Strains showed a remarkable homogeneity in fatty acids content and whole‐cell protein profiles and principal component and cluster analysis did not reveal any grouping according to original host or geographical origin. However, X.c. pv. pruni strains can be grouped apart from the other X. campestris pathovars. There appears to be no pathogenic specialization among the strains tested, however, they varied in aggressiveness to host plants and host plant in susceptibility. The most of the strains were able to cross‐infect species other that from where they were originally isolated, although, P. avium did not show any symptom of disease. P. persica cv. Sentry and P. salicina cv. Globe Sun, recently licensed as resistant to X.c. pv. pruni. were infected, although to a lesser extent, by some strains.
First Report of Phytoplasma Infection in Olive Trees (Olea Europea L.)
Authors: Pollini C. Poggi , Bissani R. , Giunchedi L. , Vindimian E. 
Published: May 2008

AbstractIn the Sarca valley (Trento, north Italy) the presence of olive trees (Olea Europea L.) with yellow symptoms in a few branches was observed. Some leaves showed diffuse chlorotic mottling affecting almost all the blade, while others showed mottling with green and yellow areas: leaf deformation was also sometimes present. Phytoplasmas were only detected in olive trees with yellow leaves by polymerase chain reaction (PCR) amplification and subsequent restriction fragment length polymorphism (RFLP) analysis. The results obtained suggested a high similarity between this phytoplasma and the elm yellows phytoplasma. This is the first time that a phytoplasma has been reported in the genus Olea.
The Role of Infective Plant Debris, and its Concentration in Soil, in the Ecology of Tomato Mosaic Tobamovirus—a Non‐vectored Plant Virus
Authors: Pares R. D. , Gunn L. V. , Keskula E. N. 
Published: May 2008

AbstractOnly a few plants in a crop are generally thought to become infected by abiotic soil transmission. In glasshouse experiments we have induced almost total infection in tomatoes growing in soil with infective debris, but levels of infection are dependent upon certain conditions. We found that as the inoculum concentration decreased (i) a greater percentage of the infections were either latent (symptomless) or restricted to roots and (ii) infection levels decreased. Thus, apparent infection (based on symptoms) of 0. 10% was in reality 0 60–70% based on enzyme‐linked immunosorbent assay and immunoelectron microscopy testing of roots and leaves. This occurred whether seedlings or seed were planted into infected mix. Under conditions in which minimal root damage was caused (planting seed) or roots were mechanically inoculated only once, almost all systemically infected plants were symptomless.
Effects of Plant Contact, Inoculation Pattern, Leaf Wetness Regime, and Nitrogen Supply on Inoculum Efficiency in Rice Sheath Blight
Authors: Castilla N. P. , Leaño R. M. , Elazhour F. A. , Teng P. S. , Savary S. 
Published: May 2008

AbstractAn experimental design was developed which allowed the measurement of inoculum efficiency (IE) represented by lesions of a leaf‐borne disease such as rice sheath blight. In this design. IE is measured as the ratio of newly established lesions on trap plants relative to the inoculum present in a canopy, i.e. lesions artificially established on source plants, IE of the rice sheath blight pathogen, Rhizoctonia solani, was studied under semi‐controlled conditions in which the effects of the following factors were measured; contact frequency among host tissues, amount and location of inoculum in the canopy, leaf wetness regime, and nitrogen content of the host plant. The conduciveness of these factors to sheath blight infection was measured in terms of IE which was expressed as the ratio of the density of daughter lesions on trap rice hills to the density of mother lesions on the inoculated quadrat hills. IE generally declined with the three successive batches of trap hills used in the experiments. It was significantly higher at closer plant spacings and under interrupted leaf wetness regimes. IE was not affected by the amount, nor by the location, of inoculum (mother lesions) in the canopy, but was significantly lower in hills with high total nitrogen content.
Systemic Migration of Pseudomonas syringae pv. avellanae in Twigs and Young Trees of Hazelnut and Symptom Development
Authors: Scortichini M. , Lazzari M. 
Published: May 2008

AbstractAt the beginning of October 1992 and 1993, healthy adult and young trees of hazelnut, cultivars Tonda Gentile Romana and Nocchione, were inoculated with a Pseudomonas syringae pv. avellanae strain through leaf scars located midway from the tip of the twig. In adult trees, the systemic migration and the population level of the pathogen were monitored during autumn and winter by means of weekly to monthly isolation and countings. In young plants, the possible displacement of the bacterium was checked in May by sampling different sites of the plant. At each sampling, the presence of internal and external symptoms was carefully assessed. During the 2‐year study, the results on migration and symptom development were consistent between the cultivars. Until the end of February. P.s. pv. avellanae colonized for approximately 45 mm, only the trait of the twig below the site of inoculation. At that time the population level ranged, in the farthest point reached by the pathogen, from 4.1 to 5.6 = 104 cfu/3 mm of twigportion. During March the pathogen was recovered from the tip of the twig. The first sign of disease was noticed in November as brown discolouration of the epidermis near the site of inoculation as well as internal necrosis of the vascular tissue. In young trees. P.s. pv. avellanae from the twig reached the branches, collar and roots from where it also colonized the branch which did not carry an inoculated leaf scar. Extensive twig dieback was noticed during April, whereas in June, most of the adult trees inoculated in autumn with approximately 25000 cells of the pathogen, randomly distributed in 25 sites of the crown, wilted completely. The role of leaf scars as a favourite site of penetration exploited by the pathogen as well as phytosanitary measures are discussed.