bluuebunny/crossref_metadata_2025_split huggingface dataset:
Furcraea Necrotic Streak Virus: An Apparent New Member of the Dianthovirus Group
Authors: Morales F. , Castaño M. , Calvert L. , Arroyave J. A. 
Published: May 2008

AbstractThe causal virus of the ‘macana’ or necrotic streak disease of fique (Furcraea spp.), the most important fiber crop in Colombia, South America, was further characterized in this study. The virus has isometric particles ca. 34 nm in diameter, with an A 260/280 ratio of 1.64, a single protein species of mol.wt. 40,000, and two single stranded RNA molecules of approximately 4,000 and 1,600 bases. The virus was observed in the cytoplasm of infected leaf and root cells as mature virions, sometimes associated with electron‐dense, tubular inclusions. Immunoenzymatic assays of different fique plant organs demonstrated that the virus is consistently detected only in the roots. The fique virus was serologically related to red clover necrotic mosaic virus (RCNMV) and hybridized with RCNMV RNA1 and RNA2 cDNA clones. We propose the name furcraea necrotic streak virus (FNSV) for this new member of the dianthovirus group.Zusammenfassung Furcraea necrotic streak virus: Anscheinend ein neues Mitglied der Dianthovirus‐Gruppe In dieser Arbeit wurde das Erregervirus der “macana‐” oder necrotic streak‐Krankheit von Furcraea spp., der wichtigsten Faserkultur in Columbien, Süd‐Amerika, näher charakterisiert. Das Virus besteht aus isometrischen Partikeln ca. 34 nm im Durchmesser, mit einem A 260/280‐Verhältnis von 1,64, einer einzelnen Proteinspezie mit einem Molekulargewicht von 40 000 und zwei einzelkettigen RNS‐Fäden aus ca. 4 000 und 1 600 Basen. Das Virus wurde in Cytoplasmen infizierter Blattund Wurzelzellen als reife Virionen beobachtet, die gelegentlich mit elektronengesättigten, rohrförmigen Einschlüssen assoziiert waren. Immunoenzymatische Assays unterschiedlicher Furcraea‐Pflanzentile zeigten, daß das Virus nur in den Wurzeln konsequent zu beobachten war. Das Furcraea‐Vims war serologisch mit dem red clover necrotic mosaic virus (RCNMV) verwandt und konnte mit RCNMV RNS1 und RNS2 cDNS‐Klonen kreuzen. Der Name furcraca necrotic streak virus (FNSV) wird für dieses neue Mitglied der Dianthovirus‐Gmppe vorgeschlagen.
Electron Microscopy Studies of a Xylem‐Limited Bacterium in Sweet Orange Affected with Citrus Variegated Chlorosis Disease in Brazil
Authors: Chagas Cesar M. , Rossetti Victoria , Beretta Maria J. G. 
Published: May 2008

AbstractCitrus variegated chlorosis (CVC), a serious disease affecting sweet orange (Citrus sinensis Osb.) groves in São Paulo and Minas Gerais States, Brazil, was first observed in 1987 and found to be associated with a Gram‐negative, xylem‐limited bacterium (GVG‐B). Electron microscopic studies revealed that the bacterium may appear in situ evenly distributed in the lumen of the tracheary elements and, occasionally, embedded in a lucent matrix adhering to the inner surface of the cell wall elements. GVG‐B measured 1–3.5 μm × 0.3–0.5 μ m and appeared to be at different developmental stages; fibril‐like structures were seen attached to bacteria. GVG‐B rippled wall showed a periodical or annulated structural arrangement with thickness from 25–35 nm in the furrows and 45–55 nm in the ridges. The wall consisted of 3 layers, i.e., an outer, an inner (each comprised of 3‐layered unit membrane structure) and a middle peptidoglycan layer. DNA‐like threads and ribosome‐like granules were present in the cytoplasm. GVG‐B is structurally and morphologically similar to Xylella fastidiosa of which it could be a citrus strain or a strain from other hosts adapted to citrus.Zusammenfassung Elektronenmikroskopische Untersuchungen eines im Xylem‐limitierten Bakteriums bei Süßorangen in Brasilien, die mit citrus variegated chlorosis disease infiziert sind Citrus variegated chlorosis (CVC), eine bedeutende Citruskrankheit bei Süßorangen (Citrus sinensis Osb.) in Plantagen in den brasilianischen Staaten Sao Paulo und Minas Gerais, wurde zum ersten Mai 1987 beobachtet, auch wurde ein Zusanimenhang mit einem Gram‐negativen, im Xylemlimitierten Bakterium (CVC‐B) festgestellt. Elektronenmikroskopische Untersuchungen haben gezeigt, daß das Bakterium in situ gleichmäßig im Lumen der Leitelemente verteilt sein kann, und auch manchmal in einer klaren, an der inneren Oberfläche der Zellwandelemente anhaftenden Matrix eingebettet. CVC‐B maß 1–3,5 μm × 0,3–0,5 μm und schien in unterschiedlichen Entwicklungsstadien zu sein; fibrilähnliche Strukturen waren mit den Bakterien verbunden. CVC‐B hat eine gekräuselte Wand, die eine regelmäßge oder geringelte strukturelle Anordnung zeigte. Die Wandstarke betrug 25–35 nm in den Rillen und 45–55 nm bei den Kämmen. Die Wand bestand aus 3 Schichten, d. h. einer aufieren, einer inneren (jede bestehend aus einer 3‐schichtigen Membranstruktur) und einer mittleren Peptidoglycanschicht. Im Cytoplasma befanden sich DNS‐ãhnliche Fäden und Ribosom‐ähnliche Körnchen. CVC‐B ist von der Struktur und der Morphologie mit Xyelella fastidiosaähnlich und könnte ein Stamm für Zitrusarten sein oder ist ein von einem anderen Wirt adaptierter Stamm von X. fastidiosa.
Accumulation of a Complex of Pigments in Sorghum Mesocotyls in Response to Wounding
Authors: Lopez A. M. Q. , Pascholati S. F. 
Published: May 2008

AbstractSorghum mesocotyls upon mechanical injury with an abrasive (carborundum) or inoculation with the fungi Helminthosporium carbonum (non‐pathogen) or Colletotrichum graminicola (pathogen) accumulate a methanol‐soluble pigment complex with an absorption maximum around 480–490 nm. Spectral and thin‐layer chromatographic analyses showed that the complexes which accumulated either in response to wounding or inoculation are similar. Thus, it is suggested that the accumulation of the pigmented phytoalexins in sorghum mesocotyls is a non‐specific response of the tissues towards mechanical injury or fungal infection.
Identification of a Cross Between Two Compatible Isolates of Magnaporthe grisea (Hebert) Barr and Genetic Analysis of Avirulence/Virulence of Rice
Authors: Silué Drissa , Notteghem Jean Loup 
Published: May 2008

AbstractA cross was successful between two field isolates of Magnaporthe grisea Guy 11 and CD 128, both pathogenic to rice. One ascospore isolated in this cross could be backcrossed to the most fertile parental isolate Guy 11. Backcrosses to CD 128 were not compatible. All progenies were inoculated to seven rice varieties in order to analyze the genetic basis of avirulence. Avirulence to Kusabue was found to be controlled by one gene. Two other controls of avirulence to rice were shown: a) two independent genes involved in avirulence to Pi‐n°4, both required by the isolates for virulence expression, b) two independent genes, each one leading to virulence on the rice varieties K 1 and Aichi asahi. Implications of these results to Flor's gene‐for‐gene hypothesis are discussed.
Effekt und Risiko des Knöllchentests auf Braunfäuleresistenz bei Kartoffelsämlingen im System der Auslese in der Phytophthora‐Resistenzzüchtung
Authors: Darsow U. 
Published: May 2008

AbstractThe effects and risks involved with the small tuber assay in plant breeding programmes with potato seedlings for resistance to Phytophthora infestansIn an assay which involved 838 potato seedlings, the relative resistance to leaf‐Phytophthora (KRG) was tested at the 4–6 leaf growth stage, and the relative tuber resistance to infection was determined on small pot‐grown tubers (BK) and, in the following 2 years, in slices from field‐grown potatoes (Bs). The small tuber assay is described and its value as a measure of disease resistance, compared with the potato slice assay, discussed. Among 357 leaf‐Phytophthora susceptible clones (KRG≤ 5) were 10 clones with a good to very good tuber resistance. 18 of 204 leaf‐Phytophthora highly resistant idiotypes were extremely susceptible to tuber rot. After discarding those seedlings which showed KRG‐values ≤ 5 and BX‐values ≤ 5, 208 of the remaining 241 (= 86 %) tuber rot resistance carrying seedlings were selected. 14 % of the clones which showed adequate resistance in the potato slice assay were falsely discarded according to the small tuber assay. 80 clones remained as ballast in the field trials (BK≤ 5, Bs≤ 6.4), 160 (33 % of the idiotypes tested) had been correctly eliminated. The work‐intensive small tuber assay presents a possibility by which breeding material can already be reduced in the seedling stage. In this respect there must be a pronounced genetic differentiation present in the potato population and the selection procedure carried out must not be too harsh.
The Establishment and Structure of Latent Infections with Monilinia fructicola on Apricots
Authors: Wade G. C. , Cruickshank R. H. 
Published: May 2008

AbstractLatent infections of apricot fruit with Monilinia fructicola were initiated by inoculation at shuck fall and 43 and 63 days after shuck fall. The fungus entered via the stomata and penetrated a guard cell through the thin walled region at the stomatal pore. The fruit tissue responded by death of cells around the point of infection, suberization of walls of surrounding living cells and accumulation o phenolic compounds in cells up to 20 distant. Periderm developed around lesions formed at shuck fall but was absent from those formed 65 days later. When the fruit ripened, approximately 100 days after shuck fall, viable hyphae in latent infections escaped from the lesions by growing out between the cuticle and epidermis or just below the epidermal cells. Outbreak was more efficient from later inoculations and only a small proportion of latents initiated at shuck fall became invasive.
Studies on Antagonistic Effects of Trichoderma Isolates Against Phytophthora cactorum
Authors: Lederer W. , Lorenz K.‐H. , Seemüller E. 
Published: May 2008

AbstractBioassays were used to demonstrate the antibiotic effect of Trichoderma isolates on P. cactorum. When both fungi were grown on benomyl‐containing PDA medium, the mycelial growth of Trichoderma was suppressed. However, the production of antibiotics by this fungus remained active, leading to inhibition of the mycelial growth of P. cactorum. The antibiotic effect of Trichoderma on zoospores and cysts was tested on a PDA substrate precultured with Trichoderma on cellophane sheets. On the substrate of some Trichoderma isolates, lysis of zoospores, formation of extracellular vesicles, and hypertrophy of the water expulsion vesicle did occur, both resulting in the death of the zoospores. Conidial suspensions of Trichoderma isolates also induced zoospore lysis. It is presumed that membrane‐active peptide antibiotics (peptaibols) are involved in zoospore lysis. The peptaibol paracelsin caused lysins of zoospores at a concentration of 2.5 × 10−4 M. The effect on cysts depended on the Trichoderma isolate tested and the age of Trichoderma preculture. Old cultures (after beginning of sporulation) affected cysts more severely than young cultures (before sporulation) which usually were not lethal to the cysts but induced preferably microsporangium formation, inhibition of cyst germination, and retardation of germ tube growth.
Production of Fumonisins by Fusarium moniliforme Cultures Isolated from Jimsonweed in Mississippi
Authors: Abbas HamedK. , Vesonder R. F. , Boyette C. D. , Hoagland R. E. , Krick T. 
Published: May 2008

AbstractEight Fusarium spp. were isolated from greenhouse‐grown jimsonweed (Datura stramonium L.) in Mississippi in 1990. Four isolates of Fusarium moniliforme were obtained and when grown on autoclaved rice, produced 115 to 3,200 mg/kg fumonisin B1, (FB1). Other fumonisin‐related compounds, such as FB2, FB3 and FB4 were also produced at levels of 240, 210 and 160 mg/kg, respectively. F. semitectum (1 isolates) was negative for production of fumonisin and other phyto‐toxins. F. oxysporutn (1 isolate) produced only 3.5 g/kg moniliformin. This is the first report of production of fumonisins by F. moniliforme isolated from weeds such as jimsonweed.
Use of Trichoderma harzianum and Gliocladium vitens for the Biological Control of Post‐emergence Damping‐off and Root Rot of Cucumbers Caused by Pythium ultimum
Authors: Wolffhechel H. , Funck Jensen D. 
Published: May 2008

AbstractThe antagonist strains Gliocladium virens G2 and Trichoderma harzianum T3 originally isolated from Pythium suppressive peat, and two benomyl‐resistant strains of T. harzianum, T12B and T95, were evaluated as biological control agents of damping‐off and root rot of cucumbers in sphagnum peat caused by Pythium ultimum. All strains were equally effective when applied as 1 % peat‐bran preparations, whereas the effectiveness of disease control was reduced at higher concentrations of the antagonists. The two wild‐type strains were also found to be effective when applied as conidial suspensions, and in this case no reduction in disease control was seen at higher concentrations. G. virens G2 and T. harzianum T12B showed antibiotic activity against P. ultimum in in vitro tests; however there were no signs of mycoparasitism of P. ultimum by any of the antagonist strains.
Hyperparasitic Attack of Trichothecium roseum on Conidia of Pestalotiopsis funerea
Authors: Urbasch Irene 
Published: May 2008

Abstract Trichothecium roseum (Tr) has been shown to be a highly effective hyperparasite on conidia of Pestalotiopsis funerea (Pf) in vivo and in vitro.The stages of this spore parasitism are:positive tropism of Tr towards Pf conidia, contact between Tr and Pf, formation of simple or lobed appressoria of Tr on the host conidial surface, penetration of the attacked host cells from the base of the appressoria, development of host‐internal, mostly branching parasitic hyphae by Tr, desintegration, lysis and death of the parasitized host cells, exit of Tr from the destroyed host cells and its intensive sporulation over Pf remnants.Pf did not show any defence reactions against the attack by Tr.In addition to the antagonistic activities of Tr against Pf reported previously, which are due to extracellular toxins released by Tr, direct hyperparasitism is a second mechanism of antagonism, which contributes to the successful competitive ability of Tr in this fungal interaction.
Chitinase Activity in Stylosanthes guianensis Systemically Protected Against Colletotricbum gloeosporioides
Authors: Brown AverilE. , Davis RobertD. 
Published: May 2008

AbstractThree‐ and four‐fold increases in chitinase activity were detected in the youngest, fully expanded leaf (L1) of Stylosanthes guianensis cv. Endeavour following inoculation of the second youngest, fully expanded leaf (L2) with virulent Type B and Type A isolates of Colletotrichum gloeosporioides compared with chitinase activity in L1 leaves of uninoculated plants. Only small increases in β‐1,3‐glucanase were detected in L1 leaves of systemically protected plants. Chitinase activity was maximal in leaf L1 36 to 48 h after inoculation of leaf L2, and this was coincident with the onset of resistance to anthracnose in L1 leaves. Chitinase activity also increased in L1 leaves inoculated with a weakly pathogenic isolate of C. gloeosporioides. Resistance developed in these L1 leaves to subsequent infection by a virulent isolate of the pathogen approximately 36 h after protective‐inoculation with the weakly pathogenic isolate.Two chitinase isozymes, with molecular weights of 65,000 daltons (pI 3.1) and 54,000 daltons (pI 4.0), were separated from extracts of C. gloeosporioides‐challenged S. guianensis cv. Endeavour leaves. S. guianensis chitinase caused death of C. gloeosporioides hyphae, particularly in the presence of β‐1,3‐glucanase. Mycelial viability declined as activity of chitinase was increased in mixtures containing a fixed activity of β‐l,3‐glucanase.
Time and Site of Inoculation of Maize for Optimum Infection of Ears by Stenocarpella maydis
Authors: Bensch M. J. , van Staden J. , Rijkenberg F. H. J. 
Published: May 2008

AbstractThe optimum inoculation position on the maize plant, and optimum time of inoculation with Stenocarpella maydis for artificial induction of ear rot were determined in field trials. The placement of a conidial suspension on the shank at silking resulted in the highest incidence of S. maydis ear rot.
A Histological Evaluation of Induced Resistance to Phytophthora infestans (Mont.) de Bary in Potato Leaves
Authors: Strömberg Anita , Brishammar Sture 
Published: May 2008

AbstractSystemically induced resistance against Phytophthora infestans in the potato cultivar ‘Bintje’ was studied histologically at the light microscopy level on the leaf surface, in the epidermis and in the mesophyll of challenged potato leaves. Systemic disease resistance was induced by a local pre‐infection with the same fungus. On the leaf surface of induced plants, the germination of cysts was enhanced. In the epidermis of induced plants, papilla deposition increased and penetration decreased, whereas in the mesophyll of induced plants the spread of hyphae was reduced. It is suggested that the reduction of disease severity in induced plants is the result of the combined action of several successive defence reactions.
Occurrence and Pathogenicity of Fusarium Species in Banana Fruits
Authors: Jiménez M. , Logrieco A. , Bottalico A. 
Published: May 2008

AbstractBanana fruits were studied over a six‐month period in order to determine the incidence of species of the Fusarium genus and assess their potential pathogenicity. The 72 samples studied were commercially available in Italy and Spain, where they were brought from Panama, Ecuador and Canary Islands. Among the species detected in the fruits, Fusarium semitectum var. majus Wollenw. was predominant, followed by F. moniliforme Sheld., F. solani (Mart.) Appel & WoUenw., F. oxysporum Schlecht., F. proliferatum (Matsushima) Nirenberg, F. graminearum Schw., F. camptoceras WoUenw. &C Reinking, F. subglutinans (WoUenw. & Reinking) Nelson et al., F. dimerum Penzig in Sacc, F. acuminatum EU. & Ev., and F. equiseti (Corda) Sacc. Fusarium proliferatum had never been reported to occur as contaminating fungi in banana fruits to date. Fusarium subglutinans, F. acuminatum and F. graminearum were found to be the most markedly pathogenic of all. The lack of noticeable differences in relation to the incidence of the different species isolated from the samples indicates that the mycoflora found is typical of this fruit and does not depend on its origin.
Evaluation of Biological and Chemical Treatments for Control of Crown Gall on Young Apple Trees in the Kootenay Valley of British Columbia
Authors: Utkhede R. S. , Smith E. M. 
Published: May 2008

AbstractField trials at Creston in 1988, 1989, and 1990 on silty loam soil naturally infested with Agrobacterium tumefaciens showed that Agrobacterium radiobacter strain K84 did not control crown gall on young Antonovka apple trees when apphed as a root‐dip treatment. Copper oxychloride applied as a root‐dip treatment at 2.5 and 5.0 g ai/1 and sewage sludge applied at 260 g per tree as broadcast were effective in reducing crown gall infection but these treatments were toxic to young apple trees in 1989. Lower rates of copper oxychloride, 0.3, 0.6 and 0.9 g ai/1, and sewage sludge at 130 g per tree, did not control crown gall in the 1990 field trial. The biological treatment with the strain AB8 of Bacillus subtilis applied as a root‐dip effectively controlled crown gall and was not phytotoxic to young Antonovka apple trees. These results suggest that strain AB8 of B. subtilis has the potential to control crown gall on young apple trees under field conditions.
Effect of Thermal and Cycloheximide Pre‐treatments on Light‐Dependent Necrosis Formation to Rice Leaves byPyricularia oryzae Toxin(s)*
Authors: Arase S. , Nozu M. , Iedome M. , Honda Y. , Yamaji Y. 
Published: May 2008

AbstractEffects of thermal and cycloheximide pre‐treatments on light dependent‐necrosis formation by Pyricularia oryzae toxin(s) on cv. Sekiguchi‐asahi were investigated. Thermal treatments of rice leaves at 55 °C for 10 and 15 sec significantly suppressed leaf necrosis formation. Such heat‐induced insensitivity of rice leaves to toxin(s) was greater at a thermal treatment of 55 °C for 15 sec than that of 55 °C for 10 sec. Cycloheximide pre‐treatment also suppressed leaf necrosis formation under light.
Induction of Systemic Resistance to Tobacco Powdery Mildew by Tobacco Mosaic Virus, Tobacco Necrosis Virus or Ethephon
Authors: Marte M. , Buonaurio R. , Della Torre G. 
Published: May 2008

AbstractLocal infections of either TMV or TNV in tobacco plants cv. Havana 425 (hypersensitive to TMV) proved effective in inducing systemic resistance to subsequent inoculation with the powdery mildew fungus Erysiphe cichoracearum DC. The proportion of leaf surface invaded by this pathogen and the amount of conidia it produced were both significantly lower in virus inoculated plants than in non‐inoculated controls. However, the decrease in sporulation rate was less regularly observed than the reduction in leaf area infected. TMV was more effective than TNV in protecting tobacco plants from powdery mildew. E. cichoracearum is thus added to the list of challenge pathogens to which TMV or TNV are known to induce resistance in the host plants.Necrotic lesions caused to the leaves by local treatment with Ethephon (an ethylene‐releasing compound) also conferred to tobacco some degree of systemic resistance to the same fungal pathogen, more frequently visible as a reduction of leaf area invaded. The protection due to the Ethephon lesions was in present experiments less marked than that of TMV. No effects against subsequent powdery mildew infection were obtained when point freeze necrotic lesions were provoked on the plants.
Identification of some Bacteria from Paddy Antagonistic to Several Rice Fungal Pathogens
Authors: Rosales A. M. , Vantomme R. , Swings J. , De Ley J. , Mew T. W. 
Published: May 2008

AbstractThe effect of 23 bacterial strains from ricefields in the tropics on rice seed germination and on radicle and hypocotyl development of four rice cultivars was determined. There was a varietal difference in response to seed bacterization with the different bacterial strains. Germination of cv. IR58 increased from 78 to 93 %, that of cv. IR64, from 89 to 97 %. Less effects on germination of cvs IR42 and IR36 were observed. All strains inhibited the mycelial growth of Rhizoctonia solani in vitro. The three strains, identified as Bacillus subtilis, inhibited the mycelial growth of eight fungal pathogens whereas the other strains were pathogen‐specific. Seed bacterization with these bacterial strains provided a sheath blight protection of 4. 5 to 73 % in the glasshouse trial. These 23 bacterial strains were identified by phenotypic tests using the API systems, morphological and biochemical features, and by comparison of electrophoretic patterns after sodium dodecyl sulphate polyacrylamide gel electrophoresis. Bacterial strains were identified (number of strains in brackets) as: Bacillus subtilis (3), Bacillus laterosporus (1), Bacillus pumilus (1), Pseudomonas aeruginosa (7), Pseudomonas belonging to section 1 (5), Erwina herbicola‐like (1), and Serratia marcescens (1). The features of the other four strains were similar to Serratia except for the DNAase and lipase activities.
Comparative Cytology of Rice Tungro Viruses in Selected Rice Cultivars
Authors: Cruz F. C. Sta. , Koganezawa H. , Hibino H. 
Published: May 2008

AbstractUltrastructural studies were made using plants of five selected rice cultivars infected with rice tungro viruses. In all cultivars, rice tungro bacilliform virus (RTBV) was found in both xylem and phloem, while rice tungro spherical virus (RTSV) was observed only in the phloem. In tolerant cultivars Balimau Putih and Utri Merah, plants infected with RTBV and RTSV or RTBV alone, had fewer cells containing tungro viruses than plants of the sensitive cultivar Taichung Native 1. In RTBV‐sensitive cultivars FK 135 and ASD 8 infected with both viruses or RTBV alone, electron‐dense cytoplasm was observed in most cells of the phloem. Abundant phloem necrosis was also observed in FK 135. These observations were correlated with the reaction of each rice cultivar to tungro infection.