bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation of Uredospores of the Soybean Rust Fungus (Phakopsora pachyrhizi Syd.) by Cell‐Free Culture Filtrates of the Mycoparasite Verticillium Psalliotae Treschow
Authors: Saksirirat W. , Hoppe H.‐H. 
Published: May 2008

Abstract Verticillium psalliotae isolates Taiw and Thai C are effective parasites of the soybean rust fungus. Cell‐free culture filtrates of these fungi, prepared after growth on autoclaved uredospores, contained β‐1,3‐glucanase, chitinase and protease activities and caused degradations, when rust spores were treated with them for 24 or 72 h. During these lytic processes carbohydrates, amino compounds and N‐acetylhexosamine were released. The carbohydrate fraction was composed of mannitol, arabitol, trehalose, glucose and unidentified substances showing low Rf‐values during thin layer chromatography. The amino compounds consisted of 10 amino acids (leucine and/or isoleucine, phenylalanine, glutamic acid, valine, arginine, asparagine, glutamine, serine, aspartic acid, histidine) and 5—7 substances which could not be identified. Verticillium lecanii isolate Konz is a weak parasite of soybean rust. During growth on uredospores the fungus produced culture filtrates without chitinase activity and with low total activities of β‐1,3‐glucanase and protease. Compared with V. psalliotae, culture filtrates of V. lecanii exerted lower lytic activities on soybean rust uredospores. The results are consistent with the aspect that the rapid growth of V. psalliotae on soybean rust fungus is primarily based on the secretion of lytic enzymes which make nutrients available to the mycoparasite.
Interactions between Fusarium oxysporum f. sp. lycopersici and Callus of Susceptible and Resistant Tomato Lines: Fungal Growth and Phytoalexin Accumulation
Authors: Kroon B. A. M. , Scheffer R. J. , Elgersma D. M. 
Published: May 2008

AbstractCallus cultures derived from isogenic lines of the tomato cultivars Moneymaker and Craigella, resistant or susceptible to F. oxysporum f. sp. lycopersici, were inoculated with Fusarium oxysporum f. sp. lycopersici race 1. Fungal growth was restricted on callus derived from resistant plants, after inoculation with a conidial suspension, whereas callus derived from susceptible plants was totally overgrown by the fungus within 7 days. The concentration of the phytoalexin rishitin was significantly higher in the callus culture derived from a resistant tomato line compared with the callus culture from a susceptible line, 2 and 3 days after inoculation with mycelium. The results of the experiments were compared with experiments with whole plants. Rishitin production as well as growth of the fungus was comparable with responses in plant‐fungus interaction. Therefore callus culture may be useful in studying the interaction between tomato plants and race 1 of F. oxysporum f. sp. lycopersici.
Elimination of Strawberry Mottle Virus and Strawberry Crinkle Virus from Isolated Apices of Three Strawberry Varieties by the Addition of 2,4‐Dioxohexahydro‐1,3,5‐triazine (5‐Azadihydrouracil) to the Nutrient Medium
Authors: Kondakova V. , Schuster G. 
Published: May 2008

AbstractFollowing the addition of 0.2 mg 2,4‐dioxohexahydro‐1,3,5‐triazine (DHT, formulation CKB 1130) to 1 l Gamborg's medium for organogenesis, the two viruses strawberry mottle virus and strawberry crinkle virus could not be detected in 74.4, 63.6 or 65.1%, respectively, of the plants regenerated from 0.8mm apices of the varieties Redgauntlet, Vesper and Pokahontas after their inoculation onto the indicator strain of Fragaria vesca EMK. In contrast, control explants which were not exposed to DHT proved to be 100% virus infected.
Prediction of Eyespot Severity on Winter Wheat or Winter Barley Inoculated with W‐type or R‐type Isolates of Pseudocercosporella herpotrichoides
Authors: Goulds A. , Fitt B. D. L. 
Published: May 2008

AbstractIn crops of winter wheat (1986—88) or winter barley (1987—88) inoculated with W‐type or R‐type isolates of Pseudocercosporella herpotrichoides and sown on different dates (1986) or at different seed rates (1987,1988) eyespot epidemics developed in different ways. Methods of measuring eyespot incidence/severity during crop growth were compared for their ability to predict eyespot severity at grain filling. Regressions were calculated for eyespot severity score at GS 71 on earlier measurements, either at GS 30/31 (11 methods) or from GS 22 to GS 65 (3 methods). Based on measurements at GS 30/31, all the methods predicted eyespot severity at GS 71 well in plots of winter barley inoculated with W‐type isolates (r, 0.83—0.97) but the accuracy of predictions in plots inoculated with R‐type isolates was very variable (r, 0.09—0.71). Predictions for 1987 and 1988 were less accurate in wheat than in W‐type plots of barley, but did not differ between W‐type and R‐type plots (r, 0.70—0.89). When the wheat data for 1986 were also included predictions were less accurate, especially in R‐type plots (r, 0—0.59). Generally, it was easier to predict eyespot severity at GS 71 in W‐type than in R‐type plots, especially in barley and in wheat before GS 37/39. Predictions of eyespot severity at GS 71 based on measurements before GS 25 were inaccurate for both wheat and barley. After GS 25 the accuracy of the prediction was generally good in W‐type plots and did not improve greatly except in wheat after GS 59. However, there was a steady improvement in the accuracy of the prediction in R‐type plots of barley from GS 24 to GS 53. Assessments of eyespot incidence on stems predicted eyespot severity at GS 71 more accurately than assessments on leaf sheaths on wheat after GS 37/39, but were not as good on barley until GS 53.
Abscisic Acid Suppresses the Hypersensitive Necrosis of Potato Tubers and Reverses the Arachidonic Acid‐Induced Inhibition of Plasma Membrane‐Bound ATPase
Authors: ÉRsek T. , Ladyzhenskaya E. P. , Korableva N. P. , ÁDám A. 
Published: May 2008

AbstractAbscisic acid (ABA) fully suppressed the development of the hypersensitive necrosis of potato tuber slices to crude elicitor from Phytophthora infestans and arachidonic acid (AA) if supplied before or up to 6 to 8 h after elicitor treatments. Later application of ABA only reduced the necrotic response. Added to highly purified plasma membrane preparation from tuber tissue, ABA eliminated the AA‐induced inhibition of the plasma membrane‐bound (K++ Na++ Mg2+) ATPase. It is suggested that ABA counteracts AA in the membrane.
Effect of DHT (2,4‐Dioxohexahydro‐1,3,5‐triazine) as Well as a Combination of DHT, Alkane Monosulfonate and N‐Phenyl‐N'‐p‐carboxyphenyl Thiourea on Tomato Mosaic Virus in Infected Glasshouse Tomato Plants
Authors: Christova D. , Schuster G. 
Published: May 2008

AbstractIn two consecutive trials, three treatments of tomato plants of the variety Rivermoon with the antiphytoviral substance DHT (2,4‐dioxohexahydro‐1,3,5‐triazine, 0.15%) 2 d a.i. and 2 and 7 d p.i. reduced the concentration of ToMV (tomato mosaic virus) by 62.3 and 60.5%. The average tomato yields increased by 40 and 26 % compared with the virus diseased, untreated controls, but the yields of the healthy controls were not achieved. A combined treatment of DHT, alkane monosulphonate and N‐phenyl‐N'‐p‐carboxyphenyl thiourea only resulted in a minor reduction in the ToMV titre and only a slight increase in yield, compared with the DHT‐solo treatment.
Evaluation of Tip Culture, Thermotherapy and Chemotherapy for Elimination of Peanut Mottle Virus from Arachis hypogaea
Authors: Chen W. Q. , Sherwood J. L. 
Published: May 2008

AbstractPeanut (Arachis hypogaea L.) plants (cvs Florunner and Pronto) were inoculated at the two‐leaf stage with peanut mottle virus (PMV) to obtain PMV‐infected plants. Shoot‐tips from plants grown in the glasshouse (27°C) or from plants maintained at 35°C were used for tip culture. In some experiments ribavirin was added to the culture medium at 5 mg/1, 10 mg/1, 15 mg/1 or 20 mg/1. Plants regenerated from meristems or shoot‐tips taken from virus‐infected plants were not virus‐free. After 45 days at 35°C, foliar tissue of 93 % of Florunner and 95 % of Pronto plants tested negative for PMV by enzyme‐linked immunosorbent assay (ELISA). When shoot‐tips from the plant that tested negative by ELISA were used for tip culture, no virus‐free plants were obtained. No virus‐free plants were obtained from tips cultured on medium supplemnted with ribavirin. However, when tip culture, thermotherapy and chemotherapy were combined; 80 % of Florunner and 100 % of Pronto plants were found negative for PMV.
Detection of Artichoke Latent Virus by an Indirect Dot‐ELISA
Authors: Cugusi M. , Foddai A. , Idini G. 
Published: May 2008

AbstractAn indirect Dot‐ELISA was compared with DAS‐ELISA for detecting Artichoke Latent Virus (ALV) both in purified preparations and in crude sap from “Spinoso sardo” artichoke leaves.Antigen diluted samples (1 μl) were first spotted on nitrocellulose (NC) and polyvinylidene difluoride (PVDF) membranes. After blocking, the membranes were incubated in rabbit anti‐ALV IgG, then in goat anti‐rabbit IgG—alkaline phosphatase conjugate, and finally exposed to substrate and examined for a coloured precipitate.The minimum detection levels for ALV by Dot‐ELISA were 125 pg of purified virus and 1/2,000 dilution of virus‐infected sap on NC, and 83.3 pg of purified virus and 1/4,000 dilution of virus‐infected sap on PVDF, as compared with 50 ng of purified virus and 1/1,000 dilution of virus‐infected sap detectable by DAS‐ELISA.This indirect Dot‐ELISA proved to be more sensitive and more economical than DAS‐ELISA, and can be completed in as little as 5—6 hours.
Effect of Placement and Sequence of Inoculation with Fusarium oxysporum on its Interaction with Meloidogyne arenaria on Subterranean Clover
Authors: Pung S. H. , Sivasithamparam K. , Barbetti M. J. 
Published: May 2008

AbstractThe effect of the placement of inoculum of Fusarium oxysporum at two soil depths, and the sequences of inoculations with Meloidogyne arenaria and Fusarium oxysporum on root growth and development of root disease in Trifolium subterraneum L. (subterranean clover) were investigated. The timing of infection and the proximity of root tips of the host root system to infection by M. arenaria and F. oxysporum appeared to be the major determining factors of root growth and of disease development in plants exposed to the pathogens. Immediate contact of roots with F. oxysporum (where the fungus was placed at seed level of 10 mm depth) appeared to result in more severe effects on roots in the presence of the nematode than later infection by the fungus placed at 30 mm depth. The production of galls by the nematode and early infection by F. oxysporum at 10 mm depth resulted in a severe inhibition of root growth, particularly of the lateral roots. But no such growth inhibition was evident when F. oxysporum and M. arenaria were introduced together at the lower depth of 30 mm. The lowest density of M. arenaria inoculum was sufficient to cause severe root rot if F. oxysporum was present at the host seed level. With the fungus at 30 mm depth, however, the expression of root rot appeared to be influenced by the inoculum level of the nematode. In sequential inoculation with F. oxysporum or M. arenaria, the organism added 2 weeks later had little or no effect on root development. The first organism (M. arenaria or F. oxysporum) to infect the germinated seedlings was the main cause of root growth inhibition. The organism that came into contact with the roots 2 weeks later had little or no effect on the roots. Concurrent infection by F. oxysporum and M. arenaria resulted in less M. arenaria gall production on the tap root system than those added with the nematode alone or in advance of the fungus.
Comparison of Fusarium oxysporum and Fusarium oxysporum var. redolens by Analyzing the Isozyme and Serological Patterns
Authors: Rataj‐Guranowska M. , Wolko B. 
Published: May 2008

AbstractExtracts from Fusarium oxysporum (F.o.) and F. oxysporum var. redolens (F.o.r.) isolates were compared by means of electrophoresis and crossed immunoelectrophoresis. The polymorphism of five isozyme systems allowed a distinction between F.o. and F.o.r. isolates. The isozyme patterns of three other isozyme systems did not allow this distinction between F.o. and F.o.r. to be made. Both fungi appeared almost identical serologically. Relative amounts of their corresponding proteins differed but the qualitative patterns of the proteins were nearly the same with the anti‐F.o.r. serum, only one specific antigen was detected in the extracts from F.o.r., isolates. Although the results obtained indicate a strong similarity between F.o. and F.o.r., they are not sufficient for an unequivocal statement that the fungi belong to the same species.
An Association Between High Peroxidase Activity in Lettuce (Lactuca sativa) and Field Resistance to Downy Mildew (Bremia lactucae)
Authors: Reuveni R. , Shimoni M. , Crute I. R. 
Published: May 2008

AbstractThe association between variation for pre‐infection peroxidase activity and levels of field resistance‐susceptibility to downy mildew (Bremia lactucae) was investigated in lettuce (Lactuca sativa) cultivars, accessions of L. serriola (prickly lettuce), segregating F2 populations and selected F3 families from a cross between field resistant and susceptible lettuce cultivars. A trend was apparent in this series of experiments indicating that one component of field resistance could be related to a high level of peroxidase activity prior to infection. The data suggest that in breeding programmes there could be merit in imposing primary selection for high peroxidase activity prior to field selection for resistance.
Identification of an Antifungal Compound in Unripe Avocado Fruits and its Possible Involvement in the Quiescent Infections of Colletotrichum gloeosporioides1
Authors: Prusky D. , Kobiler I. , Fishman Y. , Sims J. J. , Midland S. L. , Keen N. T. 
Published: May 2008

AbstractA new antifungal compound was isolated from peel and flesh of unripe avocado fruits and identified as 1‐acetoxy‐2,4‐dihydroxy‐n‐heptadeca‐16‐ene. The maximal concentration of the anti‐fungal monoene in unripe fruits was about 800 μg. g−1 fr.wt. During ripening the monoene decreased to 40 μg. g−1 fr.wt. concomitantly with the appearance of disease symptoms. The concentration of the previously described antifungal diene, 1‐acetoxy‐2‐hydroxy‐4‐oxo‐heneicosa‐12,15‐diene (Pruskyet al. 1982), in avocado peel was 1,600 μg. g−1 fr.wt. in unripe fruits, decreasing during ripening to 120 μg. g−1 fr.wt. At 750 μg. ml−1 the inhibition of germ tube elongation of germinated conidia by the antifungal monoene and the antifungal diene was 15 % and 44 %, respectively. A 1: 1 mixture of both antifungal compounds in concentrations ranging from 50 to 750 μg. ml−1, showed synergistic activity and increased the percent of inhibited germ tubes of germinated conidia up to 15 % over the sum of activities of the separate compounds.The results are discussed in relation to the hypothesis that the antifungal diene and the antifungal monoene are involved in the quiescence of the germinated appressoria of Colletotrichum gloeosporioides in unripe avocado fruits.
Factors Affecting Germination of Oospores of Phytophthora infestans
Authors: Chang T. T. , Ko W. H. 
Published: May 2008

AbstractWhen oospores from the pairing between A1 and A2 mating types of Phytophthora infestans were treated with 0.25 % KMnO4 solution for 15 min and incubated at 19 °C under light on a modified S+L medium, germination commenced within 4 days and reached about 70 % after 20 days. Under these conditions, more than 25 % of oospores obtained from a 4‐day‐old culture germinated. To obtain a high germination rate of P. infestans oospores, light was essential during germination but not during growth and oospore formation. The optimum time for activation of oospores with 0.25 % KMnO4 was 15 to 30 min and a suitable concentration of KMnO4 for 15 min activation was 0.25 to 0.45 %.
Fluorescent Pseudomonads Associated with Diseases of Wheat in South Africa1
Authors: Smith J. , Hattingh M. J. 
Published: May 2008

AbstractA survey of fluorescent pseudomonads associated with diseased wheat was conducted in South Africa during 1987 and 1988. Phenotypic features of 87 local strains were compared with those of 10 reference strains. Five groups were distinguished. Group 1 (nine reference and 16 local strains) was classified as Pseudomonas syringae pv. syringae. Group 2 (four local strains) was similar to group 1 but did not produce levan on nutrient sucrose agar. Group 3 (one reference and 33 local strains) also resembled P. s. pv. syringae, but did not elicit a hypersensitive reaction on tobacco. Group 4 (20 local strains) was mostly isolated from plants with atypical symptoms (total melanism) found in a single geographical region (Villiers) within South Africa. These strains had uniform characteristics, but failed to induce melanism on inoculated test plants. Group 5 (14 local strains) was not uniform. Twenty‐eight representative local strains, selected from each of the five groups, and the 10 reference strains were used in pathogenicity and virulence tests. The four most virulent local strains were used to screen 14 wheat cultivars grown commercially in South Africa. Five of the cultivars were susceptible to these strains. Symptoms on leaves of naturally‐infected plants corresponded with those already described, but the typical ear symptom (basal glume rot) was absent.
Further Investigation of the Specificity of Interactions Between Wild Lactuca spp. and Bremia lactucae Isolates from Lactuca serriola
Authors: Lebeda A. , Boukema I. W. 
Published: May 2008

AbstractSpecificity of interactions between eight Lactuca species (L. saligna, L. virosa, L. altaica, L. dregeana, L. perennis, L. tenerrima, L. tatarica, L. viminea) and two related genera (Mycelis muralis, Chondrilla juncea) and seven Bremia lactucae isolates from Lactuca serriola was studied in 96 accessions. The 35 L. saligna accessions gave no evidence for race‐specificity and a non‐host resistance is expected. L. virosa (36 accessions) showed a highly various response. A substantial part of the studied sets expressed a race‐specific resistance. L. altaica (one accession), which is closely related to L. serriola, was susceptible to all isolates used. L. dregeana (2 accessions) showed also a race‐specific response. The accessions of L. perennis (7), L. tatarica (2) and L. viminea (1) were resistant. The susceptibility of L. tenerrima (3 accessions), which is related to L. perennis, is unexpected. In Mycelis muralis (8 accessions) very often a incomplete resistance was observed. Chondrilla juncea (1 accession) was resistant to all isolates used. It can be concluded that the genetic distances between species cannot be used as a prediction for resistance or susceptibility.
Aphid Vectors of Barley Yellow Dwarf Virus in West‐Central Morocco
Authors: El Yamani M. , Hill J. H. 
Published: May 2008

AbstractThe ability of seven aphid species, collected in west‐central Morocco, to transmit barley yellow dwarf virus (BYDV) was determined. Aphids were either collected from grasses showing symptoms of BYDV infection or were allowed acquisition access to plants infected with a PAV‐like isolate of BYDV before transfer to oat test plants. BYDV transmission by six of the seven aphid species was confirmed by ELISA test; only Melanaphis donacis failed to transmit. The six newly defined BYDV vector species brings the total known to occur in Morocco to ten.
Effect of Time of Inoculation with Xanthomonas campestris pv. mangiferaeindicae on Mango Fruits Susceptibility Epiphytic Survival of X. c. pv. mangiferaeindicae on Mango Fruits in Relation to Disease Development
Authors: Pruvost O. , Luisetti J. 
Published: May 2008

AbstractSusceptibility of mango fruits to bacterial black spot disease was related to the stage of fruit development and to climatic factors (rainfall and temperature). The highest percentages of infected fruits occurred when inoculations were performed during the month just before harvest.Wounds and lenticels are effective entry sites for the bacterium. The ability of lenticels to take up bacterial inoculum was estimated using safranin. The susceptibility of lenticels to entry of the pathogen was directly related to the fruit age. X. c. pv. mangiferaeindicae can survive epiphytically on immature mango fruits. Bacterial populations around 105 c.f.u./fruit are commonly detected. Epiphytic X. c. pv. mangiferaeindicae were not detected on symptomless mature fruits. Those resident populations are an important source of inoculum for fruit infection. The number of bacterial spots occurring on the fruits is directly related to epiphytic populations.
Wind Dispersal of Alternaria alternata, a Cause of Leaf Blight of Cotton
Authors: Bashan Yoav , Levanony Hanna , Or Reuven 
Published: May 2008

AbstractIntroducing Alternaria alternata, the cause of blight disease of cotton plants, into a field of young healthy plants growing in rows cross‐wind, yielded disease foci which were spread downwind up to 7 m from the infection sources. Only light disease incidence was found in the remainder of the field. When the disease was introduced into a field of mature cotton plants grown in rows cross‐wind, randomly scattered disease foci occurred. In mature plantations where rows were parallel to the average wind direction, only limited size disease foci developed downwind, up to 16 m from the source. These foci did not developed further during the season. The number of air‐borne spores of A. alternata was significantly increased by the presence of diseased cotton plants, being highest close to the diseased plants. The spores were transferred to a distance of at least 20 m. However, the number of air‐borne spores significantly decreased 6 m from the infection source. Periodical trapping of air‐borne spores of A. alternata in a cotton growing region for 2 years, revealed that their air dispersal is local, probably at the field level. A. alternata in a cotton growing region for 2 years, revealed that their air dispersal is local, probably at the field level. A. alternata air‐borne spores were also trapped in rather low numbers regardless of the presence of infected cotton plants. However, the number of the air‐borne spores trapped was dependent mainly on the average wind direction and on the Alternaria blight epidemics occurring in the fields twice a year. It is suggested that A. alternata spores are transferred by wind for short distances but are constantly present in small numbers in the atmosphere throughout the whole year. The two peaks recorded for the number of spores present in the air above cotton crops correlate with the annual two outbreaks of Alternaria blight epidemics. In addition, both wind and plant row direction affect disease development in the fields.