bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occurrence of Anomalous Mycoplasma‐like Organisms in Grapevine Yellows‐diseased Phloem
Authors: Credi R. 
Published: May 2008

AbstractPathological changes in Vitis vinifera cv. Caveccia phloem from leaves showing symptoms of a flavescence doreé‐like disease consisted of obliteration, necrosis and collapse of the sieve elements and associated companion cells, and excessive callose accumulation in lateral sieve areas and sieve plates of apparently normal mature sieve elements. Unusual structures, also found in degenerate sieve elements of diseased leaf vein specimens, were strongly electron‐dense and bounded by a unit membrane or an electron‐transparent border, and considered to be senescent forms of mycoplasma‐like organisms. The significance of these findings in relation to possible host responses to the yellows pathogen is discussed.
Detection of the 3a Protein of Cucumber Mosaic Virus in a Cell Wall Fraction from Infected Nicotiana clevelandii Plants
Authors: Burman A. J. , Osman T. A. M. , Buck K. W. 
Published: May 2008

AbstractThe 3a protein of cucumber mosaic virus was expressed in Escherichia coli and, after purification, used to produce an antiserum. The 3a protein was detected in a cell wall fraction obtained from infected Nicotiana clevelandii leaf tissue by immunoblotting using the 3a antiserum. The 3a protein reached a maximum level 4 days after inoculation and remained at this level for a further 8 days before slowly declining. In contrast, the virus capsid protein, detected in an 80 000 g pellet byimmunoblotting using a virus particle antiserum, reached a maximum 5 days after inoculation and remained at this level for at least a further 16 days.
Effects of Leaf Wetness Duration and Inoculum Level on Resistance of Wheat Genotypes to Pyrenophora tritici‐repentis
Authors: Sah D. N. 
Published: May 2008

AbstractPercent leaf necrosis and lesion length on wheat genotypes increased markedly with increasing duration of leaf wetness (up to 24h or 48 h) following inoculation with Pyrenophora tritici‐repentis. A long wetting duration favoured less disease development on resistant (Fink's'), and moderately resistant (Bon/YR/3/F3570/KAL/BB) genotypes than on susceptible Glenlea. No significant difference in percent necrosis was detected among the upper three leaf positions within a genotype. A long wetnessduration had a varying effect on the resistance of wheat genotypes, depending upon the inoculum level. Increasing the inoculum level along with the leaf wetness period increased the per cent leaf necrosis on all three wheat genotypes tested. However, the, ranking of the genotype for resistance did not alter even after prolonged duration of leaf wetness (up to 96 h) and/or high inoculum level (12000 conidia/ml water). Various post‐inoculation wet‐periods in combination with high conidia concentrations in inoculum should be used in identifying highly resistant germplasm in breeding populations at the seedling stage of the wheats.
Use of Polyclonal Antibodies to Identify Mycoplasma‐like organisms (MLOs) From the Sudan and from Thailand
Authors: Saeed E. , Sarindu N. , Davies D. L. , Clark M. F. , Roux J. , Cousin M. T. 
Published: May 2008

AbstractRabbit polyclonal antibodies prepared against faba bean phyllody MLO from the Sudan reacted with its homologous antigen and with extracts of Catharanthus roseus experimentally infected with the same or a related MLO from Crotalaria saltiana showing symptoms of phyllody disease, as well as with extracts of naturally MLO‐infected C. saltiana growing in the field in the Sudan. The antibodies also reacted positively with extracts of C. roseus experimentally infected with Crotalaria juncea phyllody MLO and soybean phyllody MLO from Thailand.Polyclonal antibodies prepared against an MLO associated with witches' broom disease in C. juncea reacted positively in ELISA tests with homologous antigen extracts from naturally infected C. juncea as well as with extracts from experimentally infected C. roseus and with extracts prepared from Sesamum indicum plants with phyllody symptoms growing in Thailand. There was no reaction between these antibodies and extracts from C. roseus plants infected with the MLOs associated with C. juncea phyllody or with soybean phyllody.No cross reactions were observed among the antigens and antibodies of the two MLO groups by immunoflorescence, ELISA or western blotting. However, the molecular weight of the principal protein antigen, determined by SDS‐polyacrylamide gel electrophoresis (SDS‐PAGE) and western blotting was the same for both types of MLO.Serologically‐similar MLOs thus occur in the Sudan and in Thailand, where they are associated with phyllody symptoms in C. saltiana and faba bean and with C. juncea and soybean, respectively. A second, serologically distinct MLO group was also found infecting C. juncea and S. indicum in Thailand but MLOs from this group have not yet been identified in crops from the Sudan.
Origin of Early Attacks of Sclerotinia Stem Rot on Winter Oilseed Rape (Brassica napus sub. sub. sp. oleifera var. biensis) in the UK
Authors: McQuilken M.P. , Mitchell S. J. , Archer S. A. 
Published: May 2008

AbstractStudies in artificially infested field plots of winter oilseed rape showed that mycelia originating from both sclerotia and ascospores of Sclerotinia sclerotiorum can initiate early attacks of sclerotinia stem rot. Disease symptoms appeared in early November in plots previously infested with sclerotia in September. There was a 6–7 week period from artificially inoculating plants with ascospores in October to observing disease symtoms in December. The primary sites of infection for both typesof inocula were the laminae and petioles of senescent and frost‐damaged leaves. Following primary infection, mycelia of the pathogen spread by plant to plant contact, causing secondary infections of neighbouring plants. Sclerotia developed on diseased plants and high numbers were returned to the soil. The importance of these findings to the epidemiology of the disease are discussed.
The Efficacy of Mixtures of Susceptible and Resistant Hosts to Two Wheat Rusts of Different Lesion Size: Controlled Condition Experiments and Computerized Simulations
Authors: Lannou C. , de Vallavieille‐Pope C. , Biass C. , Goyeau H. 
Published: May 2008

AbstractControlled‐environment experiments and computerized simulations on wheat yellow rust and wheat brown rust epidemics indicated that mixtures of resistant and susceptible hosts controlled parasites with small lesions more effectively than parasites with large lesions. Experiments were conducted on seedlings, during two parasitic cycles. Yellow rust lesions were about 200 times larger than those of brown rust. The measured efficacy of seedling mixtures in reducing disease spread was 22 % for yellow rust and 46 % for brown rust. Computerized simulations suggested that, for a given quantity of inoculum, mixture efficacy was limited for a large‐lesion parasite because of fast host‐plant saturation.
Brown Discolouration of Mushrooms Caused by Pseudomonas agarici
Authors: Geels F. P. , Hesen L. P. W. , Van Griensven L. J. L. D. 
Published: May 2008

AbstractIncidence of brown‐discoloured mushrooms, differing from brown blotch disease caused by Pseudomonas tolaasii, has increased in the Netherlands and been responsible for considerable economic losses. A comparative SEM‐study of diseased tissue revealed that hyphae were collapsed and covered with a plaque in which numerous bacteria were embedded. The predominant bacterium identified was Pseudomonas agarici. Both our isolated P. agarici strain and the type strain P. agarici LMG 2112 caused brown discolouration of mushrooms after spraying with bacterial suspensions. Drippy‐gill symptoms were not observed.
Interference Between Two Strains of Bean Common Mosaic Virus is Accompanied by Suppression of Symptoms Without Affecting Replication of the Challenging Virus
Authors: Khan J. A. , Lohuis D. , Bakardjieva N. , Peters D. , Goldbach R. , Dijkstra J. 
Published: May 2008

AbstractAn unusual type of interference between two strains of bean common mosaic virus, viz. NY15 and NL3, infecting bean plants, was investigatred. Wdhen a primary leaf was inoculated with NY15 as inducer and 1–8 days later, the opposite leaf with NL3 as challenger, the plant did not develop symptoms characteristic of NL3, i.e. systemic necrosis in the top, stem and wilting and withering of the youngest trifoloclate leaves. A7‐h interval between the inoculations with inducer and challenger already sufficed to reduce the number of plants showing NL3 symptoms. Surprisingly, the amount of NL3 in the challenge‐inoculated leaf was always than that in the singly infected control, Furthermore, NY15 could not be detected in the opposite leaf until 8 days post‐inoculation and appered enen later in that leaf when challenge‐inoculated. Histological studies showed that NL3 appered later in the xylem of bothe the petiole and stem between primary leaves and first trifoliolate leaf, as compared with the singly inoculated control.The results suggest that suppression of Nl3 symptoms by Ny15 is not caused by impeding its multiplication, but by delaying the transport of NL3 to the xylem of petiole and stem.
Determination of Races of Pseudomonas syringae pv. glycinea Occurring in Europe
Authors: Abo‐Moch F. , Mavridis A. , Rudolph K. 
Published: May 2008

AbstractFifty‐eight strains of Pseudomonas syringae pv. glycinea were collected from France, Germany, Hungary, Italy, Poland, The Ukraine and the former Yugoslavia. The bacterial cultures were fluorescent on King's medium B, oxidase negative, produced levan, and induced a hypersensitive reaction (HR) on tobacco leaves within 24h. The race of each strain was determined by inoculating a set of seven differential soybean cultivars: Acme, Chippewa, Flambeau, Harosoy, Lindarin, Merit and Norchief.Conditions of plant cultivation, bacterial inoculation and plant incubation had to be standardized scrupulously to obtain reproducible results.Authentic strains belonging to races 1, 4, 5, and 6 produced the expected reactions on the differentials. However, strains of race 2 and race 4 induced identical responses on the differential cultivars. The differentiating critierion between these two races was the ability of race 2 to produce a brown diffusable pigment on King's medium B.The most prevalent race, occurring in every European country studied, was race 4. This is the most aggressive race of P. glycinea, since it infects all the cultivars of the set of differentials. From 58 strains tested, 42 belonged to race 4, 4 to race 6, and 6 to race 9. For two strains race identification was impossible. The remaining 4 isolates did not fit into the pattern of known races. It is proposed that these strains belong to a new race (no. 10) which is similar to race 5, but can inf, ect the soybean cultivar ‘Lindarin’. On the other hand, race 10 can not infect cv. ‘Chippewa’, in contrast to race 9.
The Role of Cellulase (Endo‐1,4‐β‐Glucanase) in Gummosis Diseases in Apricot
Authors: Rotem Y. , Shoseyov O. , Sztejnberg A. 
Published: May 2008

AbstractApricot gummosis pathogens — the fungi Hendersonula toruloidea, a Cytosporina sp. and a Cytospora sp., produce cellulase (endo‐1,4‐β‐glucanase, carboxymethylcellulase, CMCase) in culture. Cytospora sp. produced significantly lower amounts of cellulase than H. toruloidea and Cytosporina sp. The tendency of cellulase accumulation inside apricot stems infected with either H. toruloidea or Cytosporina sp. is similar: most of the cellulase was found in the necrotic area, whereas comparatively small amounts accumulated at the advancing edge of the disease symptom. H. toruloidea produces cellulase with a molecular mass of 76 kDa.
Efficacy of Foliar Application of Phosphates in Controlling Powdery Mildew Fungus on Field‐Grown Winegrapes: Effects on Cluster Yield and Peroxidase Activity in Berries
Authors: Reuveni M. , Reuveni R. 
Published: May 2008

AbstractSeven foliar applications of 0.025M K2HPO4 and KH2PO4 (both plus Tween 20) and the commercial systemic fungicides, Dorado (Pyrifenox) 480 EC, Penconazole EC and Benomyl, were applied at 14‐day intervals starting at 10‐cm shoot length on field‐grown Chardonnay winegrapes. Both phosphates and systemic fungicides inhibited development of powdery mildew fungus (Uncinula necator, Schw., Burr.) on fruit clusters, as compared with untreated control vines. Diseases, everity on clusters of plants treated with K2HPO4 and fungicides was 0.3 and 0.2, respectively, as compared with 1.3 on control clusters (on a 0–4 scale), for the first rating, conducted 10 days after the fifth application of fungicides and phosphates, Five days after the last application, disease severity was 3.5 on non‐treated control clusters and 0.3 and 0.8 on clusters treated with Dorado and K2HPO4, respectively. Powdery mildew infection remarkably reduced the weight of non‐treated control clusters as compared with Dorado and phosphate treated clusters. Phosphate treatment caused an increase (3‐fold) of peroxidase activity in the soluble fraction of non‐infected control berries. A remarkable peroxidase enhancement was detected in the soluble (8‐fold) and ionically bound (2‐fold) fractions from the phosphate‐treated and infected berries. Results indicate that phosphates can be used as foliar fertilizers for disease control in the field and that peroxidase might, be involved in the defense process.
Systemically Induced Resistance in Potato Cultivars with Different Degree of Resistance to Late Blight caused by Phytophthora infestans (Mont.) de Bary
Authors: Strömberg Anita 
Published: May 2008

AbstractSystemically induced resistance in potato plants (Solanum tuberosum L.) against late blight Phytophthora infestans was studied macroscopically on three potato cultivars with different degrees of resistance to late blight. The cultivars, were Bintje(2), Elin(3) and Matilda(4). Figures within brackets represent resistance to leaf late blight on a scale from 1 to 5, where 5 denotes the highest level of resistance. In vitro propagated cuttings were used in the experiments, which were, performed under controlled environmental conditions. Disease resistance was induced by a local pre‐infection with P. infestans or with the nonpathogen P. cryptogea. Induced resistance was observed on all cultivars. The protection causedby, induced resistance tended to be most intense on cv. Matilda, with 50–60% reduction in lesion formation 4 days after challenge inoculation.
Isolation and Partial Purification of a Phytotoxin Related to Pathogenic Verticillium species
Authors: Mansoori B. , Milton J. M. , Smith C. J. 
Published: May 2008

AbstractThe low molecular weight metabolites are considered as phytotoxins of pathogenic Verticillum species. The resin, Amberlite XAD‐4 was used for isolation of toxin from log‐phase culture fluids of the fungus. The toxin was purified further using, gel permeation. The isolated toxin induced chlorosis and necrosis in detached‐leaflets of susceptible tomato and potato cultivars similar to natural symptoms. The metabolite is polar, multifunctional, heat stable, cold labile with molecular weight less than 1000. The activity was retained in dried samples of the crude filtrate and kept at room temperature for up to 8 months.
Phytophthora and Pythium Associated with Feeder Root Rot of Citrus in the Transvaal Province of South Africa
Authors: Thompson A. H. , Phillips A. J. L. , Nel E. 
Published: May 2008

AbstractMild to extensive feeder root rot was present in all 23 orchards, with trees showing symptoms of citrus decline from nine areas in the Transvaal Province of South Africa. Phytophthora nicotianae and Pythium spp. were isolated from diseased roots and rhizosphere soils in all areas sampled. Isolations from diseased feeder roots showed P. nicotianae present in 26% of orchards during Spring and 61% of orchards during Autumn, while Pythium spp. were present in 56% of orchards during Spring and 65% of orchards during Autumn. In isolations from baited rhizosphere soils, P. nicotianae was present in 56% of orchards during Spring and 52% of orchards during Autumn, while Pythium spp. were present in 69% of orchards during Spring and 82% of orchards during Autumn. In rhizosphere soils, the mean population density of Pythium spp. was higher than that of P. nicotianae throughout the season. Only P. nicotianae was consistently isolated during thesurvey. Different Pythium spp. were isolated of which two were tentatively identified as P. paroecandrum and Pythium‘Gp.G’.
The Relationship between Systemic Resistance Induced by Pruning and Accumulation of Antifungal Substances in Barley Seedlings
Authors: Hiramoto T. , Abe N. , Tobimatsu R. , Shiraishi T. , Oku H. , Yamada T. , Ichinose Y. 
Published: May 2008

AbstractInfection by a compatible race of Erysiphe graminis f. sp. hordei on barley secondary leaves was significantly suppressed upon pruning of the primary leaves when E. graminis hordei was inoculated 3–12 h after the pruning, but it, was rather enhanced during 15–21 h. The accumulation of antifungal substances was detected in hot ethanol extracts of barley seedlings from 15–27 h after pruning the primary leaves. Taking the time of the infection process of a challenger (E. graminis, hordei) into consideration, timing of systemic resistance induced upon pruning coincided with the accumulation of antifungal substances.
The Infection of Festuca arundinacea by Puccinia graminis subsp. graminicola
Authors: Kulik M. M. , Dery P. D. 
Published: May 2008

Abstract Puccinia graminis subsp. graminicola has caused economically important losses of tall fescue (Festuca arundinacea Schreb.) in North America. This rust infects leaves, culms, and spikelets of the host. Initital symptoms consist of very small, chlorotic flecks, followed by long, narrow lesions. Invasive hyphae were diffuse and filamentous, changing to dense and blocky with the formation of hymenia. Tissues were extensively colonized, including development caryopses. Seedborne infection consisted of mycelium within the embryo and urediniospores carried on both surfaces of the glumes. It is not known whether caryopses that are internally infected can germinate to produce infected individuals, but this could be an important quarantine consideration. Although, at the ultrastructural level, urediniospore development in this fungus is similar to that of other rusts, we detected an additional layer at the interface of the urediniospore and its pedicel. This layer may play a role in the, release of urediniospores from their pedicels.
Damping‐off of Some Cucurbitaceous Crops in Saudi Arabia with Reference to Control Methods
Authors: Shahda W. T. , Al‐Rahma A. N. A. N. , Rageh S. A. 
Published: May 2008

AbstractIsolation of seed borne fungi from sweet melon (najed and red Queen varieties) and vegetable marrow (squash) using PDA, Plain agar media and blotters revealed the presence of Alternaria alternata (Fr.) Keissler, Fusarium semitectum var,majus from Najed melon, A. alternata (Fr.) Keissler, F. sambucinum Fuckel from Red Queen melon and A. chlamydospora Mouchacca, Cephalosporium sp., and F. oxysporum schlecht from squash. Pathogenicity tests showed, that all these fungi were highly pathogenic on their respective hosts. The optimum temperature for its growth ranged from 25–30°C and the optimum pH was 6.0.In pot trials, seed dressing with Banrot, Bavistin and Topsin‐M at the rate of 4 g/kg seed was superior in controlling the damping‐off of melon and squash. These fungicides were effective in inhibiting mycelial growth, spore germination and development of the isolated fungi. Hot water treatment at 55 C/20 min or solar heating (av. 37°C) for 90 min were next to fungicides.
Do Pathogenic Fungi Have the Potential to Inhibit Biocontrol Fungi?
Authors: Lewis J. A. , Lumsden R. D. 
Published: May 2008

AbstractMetabolites produced by the soilborne plant pathogen Rhizoctonia solani (R‐23) and Pythium ultimum (PuZ3) grown on cellophane disks placed on potato‐dextrose agar (PDA), molasses brewer's yeast agar (MYA) and wheat bran extract agar (BEA) did not significantly affect the rate of growth of isolates of the antagonists Trichoderma viride (TS‐I‐R3. Tv‐101), T. harzianum (Th‐57, Th‐87), T. hamatum (Tm‐23, TRI‐4), or Gliocladiun virens (GI‐3, GI‐21) when these antagonists were grown on the three agars containing pathogen metabolites. However. in some instances. density of antagonist mycelium growing on the agar media as well as the observable production of antagonist conidia on the agar media were reduced. Using four antagonists in liquid cultures of potato‐dextrose broth (PDB) containing metabolites of the pathogens grown on bran extract broth, metabolites from R‐23 significantly reduced mycelial dry weight of Th‐87 and GI‐21 but not that of TRI‐4 and GI‐3. On the contrary. metabolites of PuZ3 increased the mycelial dry weight of all four antagonists, Metabolites of R‐23 reduced production of conidia of only TRI‐4; metabolites of PuZ3 significantly reduced production of conidia of all four antagonists. Pathogen metabolites did not affect germination of conidia in the system used.
Apical Chlorosis Disease of Chickpea (Cicer arietinum) Caused by Tomato Spotted Wilt Virus in Brazil
Authors: Botteux L. S. , De ÁVila A. C. , Giordano L. B. , Lima M. I. , Kitajima E. W. 
Published: May 2008

AbstractA severe new disease was observed in field‐grown chickpea (Cicer arietinum L.) plants in Brasilia‐DF, central Brazil. Symptoms were mainly general chlorosis accompanied by necrosis of the new growth and plant stunting, but pods were symptomless. Host range studies, serology, particle morphology, and cytopathology showed that tomato‐spotted wilt tospovirus (TSWV) was the cause of the disease. This is apparently the first report of a chickpea disease caused by natural infection of a tospovirus.
Tissue Culture Technique to Determine the Viability of Peronospora parasitica in Brassica oleracea
Authors: Achar P. N. 
Published: May 2008

AbstractThe seed‐borne nature of Peronospora parasitica in cabbage cultivar is well established. Pure axenic growth of downy mildew of cabbage is established in vitro using modified Murashige and Skoog medium. The tissue culture technique is used to test the viability of seed borne mycelium of P. parasitica in cabbage. The percentage of seeds showing viable mycelium varied from cultivar to cultivar and a direct correlation was noticed between embryo infection and seed transmission in callus. A similar correlation was established with the seedling symptom test. The tissue culture technique to test the viability of downy mildew mycelium in cabbage was a quicker and more reliable method than the seedling symptom test. The possibility of adopting the technique by quarantine stations for seed health testing and for the in vitro studies of P. parasitica and other host systems in crucifers is discussed.