bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systemic Induction of Resistance in Phaseolus vulgaris L. to Tobacco Necrosis Virus (TNV) by Uromyces phaseoli (Pers.) Wint.
Authors: Kutzner B. , Hellwald K. ‐H. , Buchenauer H. 
Published: May 2008

AbstractPreinoculation of primary half leaves or whole primary leaves of bean plants (Phaseolus vulgaris, cv. Pinto) with Uromyces phaseoli induced resistance against tobacco necrosis virus (TNV) in the opposite half leaves and in the trifoliate leaves, respectively. For expression of systemically induced resistance an interval of at least 4 days between primary and challenge inoculation was required. The most pronounced effectiveness was found after an induction period of 6 days.Preinfectional treatment with intercellular washing fluids extracted from rust infected bean leaves (IWF‐R) also reduced disease incidence of TNV. Extracts taken 6 days after rust inoculation induced the most pronounced effect on resistance. For induction of resistance an interval of at least three days between application of IWF‐R and TNV‐inoculation was necessary. IWFs from healthy leaves (IWF‐H) did not induce resistance to TNV. The disease reductions of systemic protection by IWF‐R in the untreated primary half leaves and in the trifoliate leaves averaging 50%. The IWF‐R could be diluted to 1/4 of its original concentration without appreciable loss of the resistance‐inducing capacity.Besides the resistance inducing effects, the IWF‐R and in addition IWF‐H showed virus inactivating activity; this effect was restricted to the treated leaf area. When IWFs were applied at short time intervals either (0–8 h) before or (0–4 h) after TNV inoculation, the number of local lesions was markedly reduced. Increasing the pre‐ or postinfectional time intervals (0.5–2 dai or 6–8 hpi) diminished the activity significantly. The effectiveness of IWF‐R increased at prolonged preinfectional time intervals (e.g. 3 and 4 dai) while extracts of healthy plants were ineffective. The biphasic pattern of activity indicates that IWF‐R contains ingredients reducing virus infectivity and inducing resistance to TNV.When the transcription inhibitor actinomycin D and the translation inhibitor cycloheximide were applied simultaneously with IWF‐R 3 dai the resistance inducing effect of IWF‐R was prevented. In preliminary ultrafiltration experiments, the molecular size of the inducing ingredients of IWF‐R could be limited to 10–20 kd and those of the virus inactivating compounds to 1–5 kd.
Scanning Electron Microscopy of Olive and Oleander Leaves Colonized by Pseudomonas syringae subsp. Savastanoi
Authors: Surico G. 
Published: May 2008

AbstractLeaves of olive and oleander were sprayed with suspensions of their homologous strains (PVBa230 and ITM519, respectively) of Pseudomonas syringae subsp. savastanoi and examined by SEM. It was found that both strains multiplied on the lower surface of the leaves of both species. Preferred sites for survival and multiplication were the shields of peltate hairs on olive and the stomatal pits on oleander. The findings suggest that, at least in olive leaves, some bacteria entered the leaf tissue through the stornata but that this was not important since cells which entered the host did not cause any disease symptoms. Cells of both strains were agglomerated and cells of ITM519 were further attached to the surface of the leaf hairs on oleander by fibrillar material.Inoculated leaves did not show any disease symptoms except at leaf abscission scars on olive plants where leaves had been excised prior to inoculation. It is suggested that on both olive and oleander preexisting wounds are necessary for symptoms to develop.
Restriction Fragment Length Polymorphisms of Mitochondrial and Nuclear DNAs among Korean Races of Magnaporthe grisea
Authors: Ko Jong Hyun , Hwang Byung Kook , Hwang Byung Gap 
Published: May 2008

AbstractThree KJ‐races of Magnaporthe grisea (virulent to only japonica type rice cultivars) and seven KI‐races (virulent to either indica or japonica type cultivars) isolated from various rice‐growing areas of Korea were assayed for restriction fragment length polymorphisms (RFLPs) in mitochondrial and nuclear DNAs of the fungus. The size of mitochondrial DNA of M. grisea was estimated to be approximately 39. 8 kb. No RFLP in the mt DNA was detected among the 10 Korean races, indicating an extensive conservation in the gene composition of mt DNA without sequence variation. The identical restriction patterns of mt DNA also suggest that mt DNA of M. grisea may not be responsible for pathotypic diversity and variability. Southern blot analysis with five single‐copy DNA probes showed considerable polymorphisms. Much diversity was detected in the three KI‐races predominated during 1978–1985 in Korea. In contrast, no genetic variation was detected between other four KI‐races and three KJ‐races. RFLPs in nuclear DNA were correlated to some extent with the prevailing races in Korea. However, relationship between RFLPs in nuclear DNA and virulence of M. grisea races was inconclusive.
Comparison of the Wheat Brown and Yellow Rusts for Monocyclic Sporulation and Infection Processes, and their Polycyclic Consequences
Authors: Sache I. , De Vallavieille‐Pope C. 
Published: May 2008

AbstractSporulation capacity and infection efficiency of wheat brown and yellow rusts were measured daily in favourable controlled conditions. Monocyclic sporulation capacity for a single lesion of yellow rust was 9 times greater than for an isolated lesion of brown rust, and 40 times greater than for a lesion of brown rust at medium infection density. Infection efficiency fluctuated and reached about 40 % for brown rust but remained under 5% for yellow rust. For both fungi, sporulation capacity and infection efficiency compensated for each other, but their product, the daily multiplication factor, was greater for yellow rust than for brown rust. Progeny/parent ratio was 3 times greater for yellow rust. Effect of daily multiplication factor variations on epidemic progress was simulated using a simple matrix model. Increase in number of lesions was faster in brown rust than in yellow rust because of a latent period shorter by 2 days. Semi‐systemic growth of yellow rust fungus reduced, however, the difference between both fungi when sporulating surface was calculated.
Compatibility of Erysiphe graminis Hybrids f. sp. secalis X f. sp. Tritici with Wheat Lines Involving Resistance Genes from Rye
Authors: Oku Takashi , Tsuchizaki Tsuneo 
Published: May 2008

AbstractCompatibility of hybrid cultures Erysiphe graminis ff. sp. secalis (SI) ×tritici (t2) was tested in the laboratory with wheat cultivars involving different resistance genes and with two rye cultivars. Segregation was observed on wheat without resistance gene and with resistance genes Pm1, Pm3b and Pm3c compatible with t2, but not on wheat with resistance gene Pm2, Pm 3a, Pm 4a and Pm 5 incompatible with t2, nor on rye. It was obvious that S1 involves avirulence genes to Pm1, Pm2, Pm 3a, pm 3b, Pm 3c, Pm 4a, Pm 5. Segregation was found on wheat cultivars involving rye resistance genes Pm 7 (Transfed) and Pm 8 (Kavkaz), but cv. Transec (Pm7) was incompatible with all cultures used, because Transec involves another gene for resistance. The results indicate that hybridization between formae speciales secalis and tritici of the fungus can be a source of fungus compatibility with wheat with rye resistance, even in field conditions.
Virus Diseases of Pepper (Capsicum annuum L.) in Ethiopia
Authors: Agranovsky A. A. 
Published: May 2008

AbstractViruses occurring in hot pepper (Capsicum annuum L.) in Ethiopia during 1984–1986 were identified and their symptomatology, host range, serology, morphology and transmission described. Potyviruses were found to cause severe infections of pepper wherever the crop was observed. Disease incidence and yield loss in most surveyed areas were estimated at 40–100 % and 15–50 %, respectively. Besides potato Y and pepper veinal mottle viruses, a new potyvirus with distinctive properties was found widely distributed in Shewa and Welega Provinces. The virus, tentatively designated Ethiopian pepper mottle virus (EPMV), was shown to have an unusually narrow experimental host range and filamentous particles about 700–750 nm in length, and to be nonpersis‐tently transmitted by aphids but not transmissible through pepper seeds. Cucumber mosaic virus was detected in some locations, but appeared to be of minor significance.
Studies on Plant Viruses‐soil Colloids Interactions
Authors: Piazzolla P. , Buondonno A. , Palmieri F. , De Stradis A. 
Published: May 2008

AbstractStability and infectivity of cucumber mosaic virus, strain D (CMV‐D), associations with kaolinite and montmorillonite were determined, as affected by: i) nature of clay minerals; ii) nature of clay saturating cations; iii) exposure to dissociating salt solutions (2 M LiCl).Infectivity experiments carried out with sediments following centrifugation of the virus‐clay mixtures (sd fractions), showed that, in absence of LiCl, the highest values were obtained with kaolinite, in the order Li+= K+ > NH4+= Mg++ > Na+ > Ca++ clay saturating cations, ranging between 91 and 30 % of the untreated control, whereas comparable montmorillonite fractions gave infectivity values with all cations about 10–15 % of the control.In presence of 2 M LiCl, montmorillonite preserved infectivity of the same fraction (Lsd fraction), which, in the case of Li+‐ or Ca++ ‐saturated samples, was higher when compared with the corresponding sd values, thus revealing for these cations an amplifying effect on infection. This did not occur with kaolinite which, however, gave a Lsd fraction more infectious than the other clay.The results confirmed that clay minerals preserve infectivity of virus preparations exposed to critical conditions, thus providing an explanation for the persistence in soil of infectivity of viruses which are normally not soil‐borne. Under appropriate soil conditions these viruses may form complexes with clay minerals thus retaining an infectivity which may be enhanced by addition of cations as those contained in fertilizers.
The Hypersensitive Reaction of Soybean Cultivars to Tobacco Necrosis Virus Does Not Induce Systemic Resistance but Inhibits Plant Growth
Authors: Pennazio S. , Roggero P. 
Published: May 2008

AbstractWith soybean cultivars belonging to different maturation groups, the hypersensitive reaction to mechanically inoculated tobacco necrosis virus (TNV) did not induce systemic resistance against challenging viruses that infect locally (TNV) or systemically (alfalfa mosaic virus, AMV; soybean mosaic virus, SbMV). No form of resistance was found when resistance was tested by measuring the area and antigen content of necrotic local lesions induced by challenging TNV, or when it was tested by determining chlorophyll content and viral antigen in tissues systemically infected with AMV or SbMV.Growth of shoots was partially inhibited by the hypersensitive reaction produced by inoculation of TNV in primary soybean leaves. This inhibition was transient and did not appear to be due to stress ethylene produced by the inoculated leaves during lesion development. It was probably a consequence of nutrient depletion due to collapse of primary leaves following virus infection.
The Ability of Aphis craccivora, A. gossypii and A. citricola to Transmit Single and Mixed Viruses to Cowpeas
Authors: Roberts Julia M. F. , Thottappilly G. , Hodgson C. J. 
Published: May 2008

AbstractThe ability of populations of adult apterous Aphis craccivora, A. gossypii and A. citricola to transmit the cowpea aphid‐borne virus (CAMV) and cucumber mosaic virus (CMV) to cowpea was investigated. CMV was more readily transmitted than CAMV by all three aphid species, but was most readily transmitted by A. craccivora and A. citricola, with transmissions ranging from 64–71 %. With CAMV, the infection level with A. gossypii was higher than with A. craccivora and both were more efficient than A. citricola, although the differences were not significant. With mixed infections of CAMV and CMV, there was a higher level of CAMV transmission using A. craccivora from sequential feeding when CMV‐infected plants were fed on first followed by CAMV‐infected plants, suggesting that cowpea plants were more prone to infection by CAMV when already infected by CMV.
Coumarin Utilization Patterns of Pathogenic Races of Fusaarium oxysporum Causing Vascular Wilt of Cotton
Authors: Rutherford M. A. , Paterson R. R. M. , Bridge P. D. , Brayford D. 
Published: May 2008

AbstractFifty‐six isolates of Fusarium oxysporum from wilted cotton plants were characterized by (a) hydrolysis of aesculin and (b) utilization of the products glucose and aesculetin. Aesculin and aesculetin agars provided a simple in vitro test that enabled differentiation of pathogenic races of the cotton wilt pathogen.
The Use of Ergosterol as a Quantitative Measure of the Resistance of Cultured Tissues of Brassica napus ssp. oleifera to Leptosphaeria maculans
Authors: Gretenkort Marie A. , Ingram D. S. 
Published: May 2008

AbstractA simplified method for the quantitative assessment of the fungal lipid ergosterol was used to assess the levels of infection in tissue cultures of oilseed rape (Brassica napus ssp. oleifera) inoculated with Leptosphaeria maculans. The growth of L. maculans in liquid culture throughout a 36‐day period correlated well (r = 0·92) with the amount of ergosterol extracted from the mycelium. There were significant differences (P < 0·05) in the amount of ergosterol extracted from infected thin cell layer (TCL) explants and callus tissue of two resistant and three susceptible cultivars of oilseed rape. Amounts of ergosterol extracted from resistant cultivars were < 100 (g and from susceptible > 100 (g. The mean amounts of ergosterol extracted from shoot cultures of two resistant and four susceptible cultivars were similar to those for TCL explants and callus tissue, although the values obtained were variable. This technique can be used in in vitro breeding programmes to accurately assess the resistance of tissue cultures of B. napus to L. maculans and could also have value in conventional breeding programmes.
Host Genetic Analysis by Using Puccinia recondita tritici Induced Mutants for Increased Virulence
Authors: Saione H. A. , Favret E. A. , Franzone P. M. , Sacco F. 
Published: May 2008

AbstractMonogenic lines derived by recombination from Buck Manantial wheat, a cultivar which has durable resistance, were used as hosts to detect Puccinia recondita tritici induced mutants for increased virulence. After treatments with ethyl methane sulphonate on clone 66 of P. recondita 9 types of mutants were obtained at approximate frequencies of 1 × 10−4 and host lines were grouped in 6 classes, No increase virulence was obtained against B. Manantial after 2 cycles of treatments, but different combinations of virulences were observed on monogenic lines derived from it. Simultaneity of occurrence of some mutational events suggests complexity of virulence genes in the pathogen. At least 4 genes for incompatibility are present in B. Manantial when confronted with clone 66 and 4 to 7 mutational points are recognized in the pathogen. The specific relationships tending to equate the number of genes in both organisms would not be a general rule. Durable resistance can be explained by a combination of several specific disease reaction genes for which the pathogen population has not been able to accumulate all the corresponding alleles for virulence.
Quantification of Infection by Alternaria cassiae Using Leaf Immuno‐Autoradiography and Radioimmunosorbent Assays
Authors: Sharon Amir , Amsellem Ziva , Gressel Jonathan 
Published: May 2008

AbstractThe severity of fungal infection is usually estimated visually as a rating of injury. A more quantitative method was needed to ascertain the effect of additives used to enhance the virulence of mycoherbicidal preparations. A sensitive and accurate serological method is presented for quantitative measurement of Alternaria cassiae infection of Cassia obtusifolia. An antiserum was prepared against a homogenate of mycelium of A. cassiae. A fast and simple procedure of leaf immuno‐autoradiography was developed for the visualization of A. cassiae mycelium on inoculated leaves. A radioimmunosorbent assay (RISA) was developed for quantification of the extent of fungal infection. As little as 1. 6 ng/ ml dry weight equivalent of mycelium could be detected by RISA. There was a linear relationship between the logarithm of the RISA values and the logarithm of fungus concentration up to 300 ng/ml. Reduced sensitivity of the assay was pronounced in extracts containing 400 μ g/ml or more fresh weight of leaves. There was 30–40 % cross‐reactivity of the antiserum with two other species of Alternaria, as well as with Monilinia fructicola, and almost no reactivity was found with three other fungi tested.
Effects of Ozone Exposure on Resistance of Wheat Genotypes to Pyrenophora tritici‐repentis
Authors: Sah D. N. , Tiedemann A. V. , Fehrmann H. 
Published: May 2008

AbstractThree spring wheat genotypes, susceptible, moderately resistant or resistant to Pyrenophora tritici‐repentis (tan spot fungus) were exposed to charcoal‐filtered air and to approx. 80, 160, 240 (g m−3 ozone for five consecutive days (7 h per day). Visible leaf injury on seedling plants (three‐leaf stage) was only observed after fumigation with 160 or 240 (g m−3 O3. Amount of injury was four‐fold and 10‐fold on the susceptible genotype when compared to resistant or moderately resistant genotype at the two highest concentration of ozone, respectively. Genotypic differences to O3 tolerance were detected at the seedling growth stage (three‐leaf stage) and flowering stage but not at the stem elongation stage. A significant increase in tan spot lesion area was observed only on O3 predisposed second top most leaves of the susceptible genotype at all the three levels of ozone. Predisposition did not enhance tan spot development in resistant and moderately resistant genotypes. In a test with 12 wheat genotypes, a highly significant positive correlation (r = 0· 986, p < 0· 0001) was observed between ozone sensitivity (percent leaf area damaged due to 240 (g m−3 ozone exposure) and tan spot development (mm2 lesion area) following inoculation with P. tritici‐repentis. It indicates that wheat genotypes resistant to the tan spot fungus might be tolerant to ozone damage.
Interactions Hôte‐Parasite Entre Solanum gilo Raddli et Stemphylium floridanum Hannon et Weber: Aspects Ultrastructuraux
Authors: Clerivet A. 
Published: May 2008

RésuméLa penetration et la colonisation des feuilles de Solanum gilo par Stemphylium floridanum sont etudiees sur des plants infectes experimentalement.Les examens en microscopie electronique montrent que le parasite penetre par les stomates des feuilles puis envahit le parenchyme chlorophyllien. La desorganisation des tissus colonises et de ceux situes a distance du parasite est importante et l'ultrastructure cellulaire profondement modifiee. L'hote parait construire des barrieres a la progression du parasite par la creation de territoires necrotiques, la synthese de composes phenoliques et de callose.
Detection of Australian Field Isolates of Citrus Tristeza Virus by Double‐Stranded RNA Analysis
Authors: Habili Nuredin 
Published: May 2008

AbstractDouble‐stranded RNA analysis indicated that widespread latent infection by citrus tristeza virus (CTV) occurs naturally in a citrus variety collection at Merbein, Australia. Detection was based on the presence of the putative replicative form (RF) of the virus (ca 19. 5 kilobase pairs) and the presence or absence of three previously known putative subgenomic dsRNAs with molecular sizes of ca 3. 1,1.7 and 0.8 kilobase pairs. With the exception of some citrus relatives normally used as rootstocks, the dsRNAs were readily detectable in all the trees tested. Variability was noticed among the dsRNAs profiles of individual seedling trees of Microcitrus australasica var. sanguinea. By contrast, dsRNA patterns of trees of open‐pollinated Ellendale tangor were indistinguishable. A number of dsRNA bands found in West Indian lime infected with CTV were not detected when this isolate was graft‐inoculated to healthy sweet orange seedlings. A simple method for enhancing the sensitivity of detection of the CTV dsRNA bands by silver staining is described which involves incubating the gels in RNase A prior to staining; this allowed detection of the putative CTV RF in only 40 mg of green hark material.
Effects of Temperature on Viability of Pathogenic Fusarium Species
Authors: Kováčiková Eva 
Published: May 2008

AbstractThe viability of three species of Fusarium pathogenic to winter cereals was differently affected by temperature. F. culmorum survived in vitro in soil for 4 months at 8, 20 and 30 °C, the number of colony forming units (CFU) recorded at these temperatures after incubation being 125, 185 and 624 % respectively when compared with the number present at the beginning of the experiment. F. avenaceum and F. heterosporum barely survived at 8 °C after incubation for 4 months but at 20 °C the numbers of CFU were 314 and 380 % respectively, while at 30 °C the corresponding number tor each of these species was 200 %.At natural soil temperatures in winter, the number of CFU of F. culmorum after 4.5 months decreased to 60, 70 and 87 % of the number present at the beginning of this experiment when infested soil was buried at depths of 7–10, 15—20 and 30 cm respectively. In the upper soil layer where winter temperatures were lowest, survival of F. avenaceum and F. heterosporum did not occur. Survival rates for these two species at a depth of 15—20 cm were 20 and 5 % respectively. In the deepest layer of soil (30 cm) survival of these two species was 30 % for F. avenaceum and 10 % for F. heterosporum of the number present at the beginning of this experiment.These results demonstrate that during the early spring stages of growth of winter wheat, inoculum of F. culmorum, unlike that of F. avenaceum and F. heterosporum, is also a source of infection in the top soil layer in our climatic conditions.
Characterization of Peanut Mottle Virus in Cote d'Ivoire
Authors: Samad Abdul , Thouvenel J.‐C. , Dubern J. 
Published: May 2008

AbstractA virus, hitherto unreported in Cote d'Ivoire, was detected in groundnut plant (Arachis hypogaea) from the northern parts of the country. Infected plants showed mottling, interveinal depression, and very prominent light and dark green patches on leaves. The causal agent was characterized as a strain of peanut mottle virus, a member of the potyvirus group, on the basis of its host range, mode of transmission, physical properties, particle morphology and on the basis of its serological properties studied in comparison with these of other groundnut viruses.
Purification and Characterization of an Isolate of Apple Mosaic Virus from Rose in the USA
Authors: Wong Sek‐Man , Horst R. Kenneth 
Published: May 2008

AbstractAn isolate of apple mosaic virus, designated ApMV‐J, was isolated from rose cv. Sweet Surrender in New York State, USA. Mechanical transmission of ApMV‐J from rose to cucumber was facilitated by preparing inocula with 0.03 M sodium phosphate buffer containing 0.02 M 2‐mercap‐toethanol and 1 % polyvinylpyrolidone. Catharanthus roseus cv. Little Linda was a good virus maintenance host and Cucumis sativus cv. Lemon a good propagation host. Contaminating host proteins were substantially reduced by including polyethylene glycol in the purification protocol. Purified virus had high A260/280 nm values and contained virus particles of c 25—26 nm in diameter; most particles were isometric but a few were bacilliform. The M.Wts. of the four nucleic acids of ApMV‐J, determined in non‐denaturing and denaturing agarose gels, were estimated at 1.16, 0.98, 0.68 and 0.35 × 106 and 1.0, 0.91, 0.66 and 0.35 × 106, respectively. The viral coat protein M. Wt. was estimated to be 27 kDa.