bluuebunny/crossref_metadata_2025 huggingface dataset:
First Report of Leaf Blight of Onion Caused by Xanthomonas campestris in the Continental United States
Authors: Isakeit T. , Miller M. E. , Barnes L. W. , Dickstein E. R. , Jones J. B.
Published: May 2007

In March 1998, a leaf blight of onion (Allium cepa L. ‘1015’) was found on many plants in a plot on the Texas A&M Agricultural Experiment Station in Weslaco. The symptoms were longitudinal chlorotic areas on one side of the leaf, containing sunken, elliptical necrotic lesions. Affected leaves ultimately died. Chlorotic lesions were swabbed with 70% ethanol, and tissue from beneath the epidermis was placed in a drop sterile water for 20 min. Drops were streaked on nutrient agar and incubated at 30°C. Isolations yielded gram-negative, rod-shaped bacteria that formed dark yellow, gummy colonies on yeast dextrose carbonate agar medium, hydrolyzed starch, and had a single, polar flagellum. Analysis of fatty acid methyl ester (FAME) profiles, using the Microbial Identification System (MIS, version 4.15; Microbial Identification, Newark, DE), done at the Texas Plant Disease Diagnostic Laboratory, College Station, identified nine isolates as Xanthomonas campestris (similarity indices of 0.31 to 0.54). Tests at the University of Florida supported this identification: FAME profiles using MIS version 3.9 gave similarity indices of 0.89 to 0.95, and profiles using Biolog GN Microplates, MicroLog database release 3.50 (Biolog, Hayward, CA), gave similarity indices of 0.03 to 0.76. Leaves (15 to 20 cm long) of potted onions (cv. 1015 at the five- to six-leaf stage) were infiltrated with a suspension of bacteria (107 CFU per ml), using a needle and syringe. Plants were maintained in mist chamber in a greenhouse at 24°C. Water-soaking and development of pale green color of the inoculated leaf occurred after 2 days, followed by death after 4 days. There were no symptoms on leaves inoculated with sterile water. Pathogenicity tests on four isolates were repeated once. Bacteria were reisolated on nutrient agar from symptomatic tissue but not from controls. In the field plot, disease severity did not increase as season progressed nor were there any symptoms on bulbs. Symptoms were not observed on onion during the 1999 season. X. campestris was first reported on onion from Hawaii (1). This is the first report of this pathogen on onion in the continental United States.

Reference: (1) A. M. Alvarez et al. Phytopathology 68:1132, 1978.
First Report of a Mexican Isolate of Papaya mosaic virus in Papaya (Carica papaya) and Pumpkin (Cucurbita pepo)
Authors: Noa-Carrazana J. C. , Silva-Rosales L.
Published: May 2007

Papaya mosaic virus (PMV) is a member of the Potexvirus group and has filamentous particles of 530 nm with a positive sense single-stranded RNA of 6.6Kb. PMV was detected in Mexico in diseased papaya plants growing alone and in mixed plantations with pumpkin. Reverse transcription polymerase chain reactions (RT-PCR) and standard double-antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) procedures were used on 45 leaf samples from single plants in seven locations in southeast Mexico (States of Yucatan, Campeche, and Quintana Roo). PCR primer design was based on a GenBank sequence with accession number D13957 (1). Amplified PCR products were cloned using a TOPO TA Cloning Kit and sequenced by the dideoxy chain termination method. Twenty-six samples tested positive for PMV using one or both detection techniques: 23 of 41 from papaya and three of four from pumpkin. The two sequences reported here, YY-15 and YY-22 (from papaya and pumpkin respectively, with accession numbers AYO17186 and AYO17187), were 1180 nucleotides long and contained a fragment of ORF3, the complete ORF4 and the putative CP gene, including the 3′ end untranslatable region. Within the CP gene sequence, the amino acid sequence derived had a similarity of 88% with that of D13957 from the GenBank. The similarity of the CP between the two Mexican isolates (from papaya and pumpkin) was 94% and would therefore represent two variants of PMV. A healthy papaya plant in the greenhouse, inoculated with tissue from an infected papaya plant from the field, tested positive for PMV in DAS-ELISA. (PVX was used as a negative control). These results confirmed the identity of the isolate as PMV.

Reference: (1) T. L. Sit, M. G. AbouHaidar, and S. Holi. J. Gen. Virol. 70:2335-2331, 1989.
First Report of Dollar Spot, Caused by Sclerotinia homoeocarpa, on Poa pratensis in Saskatchewan, Canada
Authors: Smith J. D. , Gossen B. D. , Hsiang T.
Published: May 2007

Dollar spot disease affects many species of grasses in North America but has not been previously reported from Saskatchewan. In July 2000, symptoms were observed on golf course fairways in Saskatoon. No dollar spot disease was observed on adjacent putting greens or tees composed of Agrostis palustris (creeping bentgrass), perhaps because the tees and greens were grown under a higher nitrogen fertility regime. Fungicide treatments are usually not required for turf disease control during the warm, dry summer growing season in Saskatoon, and no fungicides had been applied at this location. Daytime temperatures near 25°C and heavy dew at night preceded the disease outbreak, which affected about 5% of the turf across large areas of several fairways. The fairways were originally seeded to Festuca rubra subsp. rubra (common creeping red fescue) and Poa pratensis (Kentucky bluegrass) but also contained annual bluegrass (P. annua). The disease was observed on leaf blades of all three species. In addition to 5-cm-diameter circular patches of brown grass, sharply delimited individual leaf lesions and cobweb-like aerial mycelia on the grass were observed. Fungal isolates were obtained by plating infected P. pratensis leaf blades on potato dextrose agar and then transferring to oat agar. On oat agar, isolates produced white, fluffy aerial mycelium, columnar when mature, and usually with a cinnamon base and dark brown stromata or sclerotial flakes on and in the agar. DNA was extracted from an isolate and amplified using the primers ITS1 and ITS4 (1). A 500-bp fragment presumed to contain the internal transcribed spacer region of the ribosomal DNA (ITS) was purified and sequenced (1), and it showed 96% identity with the ITS of a Sclerotinia homoeocarpa isolate, Genbank accession AF067640. To test Koch's postulates, P. pratensis cv. Loft 1757 was grown from seed in 15 ml of sand at 20°C under constant fluorescent light. Two-week-old turf was inoculated with 5-mm-diameter mycelial plugs of the fungus from 1-week-old cultures on potato dextrose agar by placing inoculum plugs on the sand. Inoculated turf was incubated in a loosely-lidded clear plastic container at 20°C under constant fluorescent lighting. After 1 week, lesions and white aerial hyphae were observed on the leaf blades, while no disease was observed on the uninoculated controls. The fungus was reisolated from foliar lesions to complete Koch's postulates. In addition to P. pratensis, both P. annua and A. palustris cv. Penncross were also inoculated and showed disease symptoms, with greater disease severity on P. annua.

Reference: (1) T. Hsiang and C. Wu. Mycol. Res. 104:16, 2000.
First Record of Pea enation mosaic virus Naturally Infecting Chickpea and Grasspea Crops in Syria
Authors: Makkouk K. M. , Kumari S. G. , Lesemann D.-E.
Published: May 2007

Virus-like symptoms not commonly encountered on most chickpea (Cicer arietinum L.) and grasspea (Lathyrus sativus L.) genotypes were noticed at the ICARDA farm near Aleppo, Syria, during April and May 2001. Primary symptoms included stunting, accompanied by leaf mottling and yellowing. The causal agent was transmitted by the pea aphid (Acyrthosiphon pisum Harris) in a persistent manner. Efficiency of transmission was 100% when aphids acquired the virus from grasspea and then inoculated lentil, whereas transmission efficiency was 21% when aphids acquired the virus from chickpea and then inoculated lentil. Samples of symptomatic chickpea and grasspea reacted strongly with the antiserum prepared against a Dutch isolate (E154) of Pea enation mosaic virus (PEMV), provided by L. Bos (Wageningen, the Netherlands) (1), using tissue blot immunoassay (2). Negatively stained preparations from chickpea and grasspea revealed typical PEMV-like isometric particles ≍30 nm in diameter. With immunoelectron microscopy, these particles were effectively trapped and strongly decorated with PEMV antibodies (immunoglobulin G diluted 1:10) provided by M. Musil (Bratislava, formerly Czechoslovakia) (4). The virus capsid protein was 22 kDa based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, typical of the PEMV coat protein, and reacted strongly with PEMV antiserum (E154) in western blots. This is the first report of PEMV naturally infecting chickpea and grasspea in Syria and, to our knowledge, the first report in West Asia. PEMV reached epidemic levels on lentil in Syria for the first time in 1994 (3). Field symptoms observed in May 2001 suggest that PEMV may also seriously affect lentil, chickpea, and grasspea crops in Syria.

References: (1) K. Mahmood and D. Peters. Neth. J. Plant Pathol. 79:138, 1973. (2) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (3) K. M. Makkouk et al. Plant Dis. 83:303, 1999. (4) M. Musil et al. Acta Virol. 14:285, 1970.
First Report of Sclerotium rolfsii on Star-cluster (Pentas lanceolata) in Taiwan
Authors: Fu C. H. , Hsieh H. J. , Yao J. C.
Published: May 2007

Star-cluster (Pentas lanceolata (Forssk.) Deflers) has recently become popular as a bedding plant in Taiwan. During the summer of 2000, a sudden wilt of 60-day-old plants was observed in a nursery in Tainan City (southern Taiwan). Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of leaves. As stem necrosis progressed, infected plants wilted and died. Necrotic tissues were covered with white mycelium that differentiated into reddish brown, spherical (1 to 2 mm in diameter) sclerotia. Sclerotium rolfsii was consistently recovered from the surface of symptomatic stem sections that were disinfected for 1 min in 0.5% NaOCl and plated on potato dextrose agar amended with 100 ppm streptomycin sulfate. Pathogenicity of three isolates of S. rolfsii was confirmed by inoculating 90-day-old plants of P. lanceolata that were grown in pots. Three plants each were inoculated with a 5-mm plug of agar with mycelium or two sclerotia of the pathogen. Inoculum was placed on the soil surface against the stem of each plant. Three noninoculated plants served as controls. All plants were kept in a growth chamber at 20 to 30°C with relative humidity >85%. The pathogenicity test was repeated. Inoculated plants developed symptoms within 7 days, while control plants remained symptomless. Sclerotia developed on infected tissues and S. rolfsii was reisolated from symptomatic tissues. Although this disease has been observed on many species of plants (1), to our knowledge, this is the first report of southern blight of P. lanceolata caused by S. rolfsii in Taiwan.

Reference: (1) Tsai, Y. P., ed. List of Plant Diseases in Taiwan. The Plant Protection Society of the Republic of China and The Phytopathological Society of the Republic of China. 1991.
Molecular and Pathogenicity Characterization of Sphaceloma manihoticola Isolates from South-Central Brazil
Authors: Alvarez Elizabeth , Mejia Juan Fernando , Valle Teresa L.
Published: May 2007

Isolates of Sphaceloma manihoticola, the asexual stage of Elsinoe brasiliensis, were collected from several regions of south-central Brazil. The isolates were obtained from samples of leaves, stems, and petioles of cassava (Manihot esculenta) and the weedy Euphorbia heterophylla (“amendoim bravo”) by directly plating infected tissue onto acidified potato dextrose agar. For pathogenicity studies, 19 isolates were inoculated onto each of two cassava cultivars, MBRA 703 as a susceptible cultivar and MBRA 12 as a resistant cultivar to S. manihoticola. MBRA 703, with the greatest pathogenicity to 58% (11) of the isolates, showed an intermediate pathogenic reaction to 16% (3) of the isolates, and was less pathogenic to 26% (5) of the isolates. MBRA 12, with a less pathogenic reaction to 63% (12) of the isolates, showed an intermediate pathogenic reaction to 16% (3) of the isolates, and was highly pathogenic to 21% (4) of the isolates. The isolates were verified as belonging to the genus Sphaceloma based on their morphological characteristics, including conidia and hyphae of monoconidial isolate. Conidia of isolates were small, thin-walled, ellipsoid to (rarely) globose, commonly with one or two gut-tules. Conidiophores were phialides, hyaline to slightly pigmented 0-to-1 septate; conidiophores from the weedy specie were phialides, hyaline to brown 0-to-2 septate producing hyaline conidia. The isolates also were verified as belonging to the genus Sphaceloma by using a poly-merase chain reaction (PCR) assay, which detected a 645-bp band in all isolates except two (1 and 6) for which the PCR product had 600 bp. Digestion of the amplified product with the enzymes MspI and CfoI allowed differences to be detected in restriction patterns among isolates. A homogeneous banding pattern was obtained for 17 of the isolates but a different restriction pattern was obtained for isolates 1 and 6 of E. heterophylla. This suggests the possibility of another species within this group of isolates. The results indicate the presence of pathogenic variation among isolates of the fungus and an isolate-host interaction, because statistically significant differences were observed between the two cassava cultivars in response to inoculation with the isolates of S. manihoticola.
First Report of Gray Leaf Spot on St. Augustinegrass in Italy
Authors: Polizzi G. , Castello I. , Picco A. M. , Rodino D.
Published: May 2007

St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) is used for lawns in southern Italy because it is much more resistant to biotic and abiotic adversities than other turfgrass species. Because few seeds are viable, this species is established by vegetative propagation. A new disease was noticed during the spring of 2002 and 2003 on cuttings of St. Augustinegrass growing in three greenhouses in eastern Sicily. The disease affected leaves and culms and caused a progressive drying of the plants. The infection was first seen on leaves as gray, necrotic spots that enlarged in high-humidity conditions to form oval, and later, spindle-shaped lesions. In association with the lesions, it was possible to observe fungal spore development and sunken areas with blue-gray centers and slightly irregular, brown margins with yellow halos. Spots were concentrated without specific arrangement along longitudinal veins and the midrib and at the base, tip, and margins of the leaf blade. Symptoms on the culms consisted of brown-to-black blotches that sometimes extended throughout the internodes. From these infected tissues, 20 explants taken from leaves and culms were cut, washed with sterile water, and placed on 1.5% water agar (WA). Later, conidia and conidiophores were obtained from colonies with a sterile glass needle and placed on 4% WA. From these plates, two monoconidial isolates were obtained and transferred to rice meal medium (1). The colonies were identified as Pyricularia grisea Cooke (Sacc.), anamorphic state of Magnaporthe grisea (Hebert) Yeagashi & Udagawa, the cause of rice blast disease and gray leaf spot disease of turfgrasses. The conidia were pyriform to obclavate, narrowed toward the tip, rounded at the base, 2-septate, 21 to 31 μm × 6 to 10 μm (average 25.7 ×8.2 μm). Pathogenicity tests were performed by inoculating leaves and culms of six St. Augustinegrass plants with a conidial suspension of the fungus (1.5 ×105 conidia per ml). The same number of noninoculated plants was used as controls. All plants were incubated in a moist chamber with high humidity at 25°C. After 6 days, all inoculated plants showed typical symptoms of the disease. Koch's postulates were fulfilled by isolating P. grisea from inoculated plants. Gray leaf spot caused by P. grisea has been a chronic problem on St. Augustinegrass since it was first reported in 1957 (2). To our knowledge, this is the first report of P. grisea on St. Augustinegrass in Italy. While it does not appear to be an important disease in the field at this time in Sicily, it could cause losses in greenhouses where vegetative material is propagated for field planting. A preliminary molecular analysis has shown a clear distinction between the tested strain and other strains isolated from rice seeds and plants in northern Italy.

References: (1) E. Roumen et al. Eur. J. Plant Pathol. 103:363, 1997. (2) L. P. Tredway et al. Plant Dis. 87:435, 2003.
First Report of Downy Mildew on Delphinium Caused by Peronospora ficariae in California
Authors: Tjosvold S. A. , Koike S. T.
Published: May 2007

Along California's central coast, delphinium (Delphinium species and cultivars) is grown as a cut flower and potted plant. In the spring of 2003, severe downy mildew was observed on various delphinium crops in Santa Cruz County. The disease was detected on cut flower Delphinium ‘Volkerfrieden’ in a greenhouse and adjacent field production areas. At a different nursery, outdoor, containerized D. grandiflorum ‘Blue Butterfly’ and Delphinium elatum (Pacific Hybrids) were also infected. Initial symptoms on leaves consisted of light green patches. These areas quickly turned dark green to blackish green and often were delimited by the central vein of the leaf. Purple-gray sporulation of the pathogen could be seen primarily on the abaxial leaf surfaces. Symptoms were most severe on older foliage. As disease progressed, the lower leaves withered and dried up, giving the plant a blighted appearance. Disease was most severe on D. grandiflorum ‘Blue Butterfly’, in which the disease affected the entire planting and blighted all foliage with the exception of the youngest leaves on the plant's central leader. For this cultivar, the diseased nursery stock had to be discarded, resulting in significant economic loss. Sporangiophores branched dichotomously, with branches ending in slender, slightly curved tips. Sporangia were slightly purplish, ellipsoid to ovoid, and measured 27 to 36 × 19 to 22 μm. Inside the tissue of older symptomatic leaves, extensive numbers of oogonia and oospores were observed. Oospores were globoid, amber to light brown, verruculose, and measured 25 to 27 μm in diameter. The pathogen was identified as Peronospora ficariae (1). Pathogenicity was demonstrated by spraying sporangial suspensions (1.0 × 104 sporangia per ml) onto the leaves of healthy, potted Delphinium elatum (Pacific Hybrids), incubating the plants in a dew chamber at 18°C for 48 h, and then maintaining them in a greenhouse (22 to 24°C). After 10 to 12 days, inoculated plants developed downy mildew symptoms, and the same pathogen sporulated sparsely on the host. If these plants were again placed in the dew chamber for an additional 24 h, leaf lesions sporulated profusely in the following 48 h. Control plants treated with water did not develop any symptoms or signs of downy mildew. To our knowledge, this is the first report of downy mildew caused by P. ficariae on cultivars of delphinium in California.

Reference: (1) G. Hall. Mycopathologia 126:51, 1994.
Possible Escape of a Recombinant Isolate of Potato virus Y by Serological Indexing and Methods of its Detection
Authors: Singh R. P. , McLaren D. L. , Nie X. , Singh M.
Published: May 2007

Surveys of commercial and seed potato fields for virus diseases (1998 to 2002) in Manitoba established that Potato virus Y (PVY) is of concern in seed potato production. To determine the prevalence of PVY strains, PVY-infected tubers identified by reverse transcription-polymerase chain reaction (RT-PCR) from surveys (2000 to 2001) were grown for symptom expression and strain characterization by strain-specific RT-PCR, bioassays, and serological assays. Of the samples collected (2000 to 2001) and tested by RT-PCR, 4.0% contained PVY. Further analysis of the PVY-positive samples by a duplex RT-PCR facilitating the simultaneous detection of common (PVYO) and tobacco veinal necrosis strains (PVYN/NTN) indicated that 37.5% contained PVYO and 63.5% contained PVYN-type isolates. Analysis of the PVYN-type samples using three monoclonal antibodies (MAbs) showed that all reacted with only the PVYO MAbs and not with the PVYN-specific MAb. Partial nucleotide sequences of both ends of PVY-RNA showed that the PVYN-type isolates resembled those reported in 1996 from Manitoba. These isolates are designated as PVYN:O. In view of the increased incidence of PVYN:O in one production area, seed tubers imported from other provinces of Canada and the neighboring United States were analyzed for PVYN:O. The PVYN:O was detected in imported seeds from Minnesota, Montana, and North Dakota.
Impact of Management Practices on Prevalence of Soybean Sclerotinia Stem Rot in the North-Central United States and on Farmers' Decisions Under Uncertainty
Authors: Mila A. L. , Carriquiry A. L. , Zhao J. , Yang X. B.
Published: May 2007

Regional prevalence of soybean Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, was modeled using management practices (tillage, herbicide, manure and fertilizer application, and seed treatment with fungicide) and summer weather variables (mean monthly air temperature and precipitation for the months of June, July, August, and September) as inputs. Logistic regression analysis was used to estimate the probability of stem rot prevalence with disease data from four states in the north-central region of the United States (Illinois, Iowa, Minnesota, and Ohio). Goodness-of-fit criteria indicated that the resulting model explained well the observed frequency of occurrence. The relationship of management practices and weather variables with soybean yield was examined using multiple linear regression (R 2 = 0.27). Variables significant to SSR prevalence, including average air temperature during July and August, precipitation during July, tillage, seed treatment, liquid manure, fertilizer, and herbicide applications, were also associated with high attainable yield. The results suggested that SSR occurrence in the north-central region of the United States was associated with environments of high potential yield. Farmers' decisions about SSR management, when the effect of management practices on disease prevalence and expected attainable yield was taken into account, were examined. Bayesian decision procedures were used to combine information from our model (prediction) with farmers' subjective estimation of SSR incidence (personal estimate, based on farmers' previous experience with SSR incidence). MAXIMIN and MAXIMAX criteria were used to incorporate farmers' site-specific past experience with SSR incidence, and optimum actions were derived using the criterion of profit maximization. Our results suggest that management practices should be applied to increase attainable yield despite their association with high disease risk.
Efficacy of Bioindexing for Graft-Transmissible Citrus Pathogens in Mixed Infections
Authors: Vidalakis G. , Garnsey S. M. , Bash J. A. , Greer G. D. , Gumpf D. J.
Published: May 2007

Biological indexing for graft-transmissible pathogens of citrus in the presence of additional pathogens was investigated. The probability for symptom expression, the efficacy of the bio-indexing tests, and the number of citrus indicators required for pathogen detection were statistically evaluated. Multiple infections did not preclude symptom expression or reduce the diagnostic efficacy of the primary indexing hosts for Citrus tristeza virus (CTV), Citrus psorosis virus (CPsV), and Citrus tatter leaf virus (Apple stem grooving virus). Symptoms of Citrus vein enation virus (CVEV) and the diagnostic efficacy of Mexican lime were suppressed by the T30 group CTV isolates, but not by other CTV isolates tested. CPsV suppressed symptom expression and diagnostic efficiency of Dweet tangor and sweet orange for concave gum. The application of alternate bioassay hosts for indexing was also investigated. Dweet tangor, sweet orange, and Citrus excelsa are not typically used for bioindexing of CVEV, however, Dweet tangor and C. excelsa detected CVEV in single infections, whereas in sweet orange, CVEV was detected only when CPsV, concave gum, or citrus viroids were present. CTV was readily detected using the alternative indicator C. excelsa, whereas only shock reacting CPsV isolates were effectively indexed by Mexican lime.
First Report of Species of Colletotrichum Causing Leaf Blotch of Liriodendron tulipifera in Argentina
Authors: Lori G. A. , Alippi A. M. , Dimenna S.
Published: May 2007

Since 1986, irregular, blotchy lesions of leaves and petioles of tulip tree (Liriodendron tulipifera L.) have been observed each summer in the city of La Plata, Argentina. Leaf spots are initially 2 to 3 mm in diameter and water soaked, and then they become brown or black with faint chlorotic margins that are more noticeable on the adaxial surface. Lesions may attain a diameter of 12 mm. Veins and petioles may also be affected and lesions may coalesce, especially at leaf margins. Surface-sterilized pieces of necrotic tissue collected from eight sites in the La Plata area were plated on potato dextrose agar and incubated at 27°C. Two Colletotrichum species were consistently isolated from the lesions. Single-spore cultures were obtained and identified as C. acutatum (1) and C. gloeosporioides (4). When cultured on V8 medium, mycelial growth of C. acutatum was tufted and pale gray, and the reverse side of colonies was buff to cream or pale gray to tan, but never dark. Hyaline conidia were buff to rosy buff en masse and elliptical or elongated with abruptly tapering ends measuring 8.04 to 13.58 × 2.68 to 3 μm. Micromorphology of conidia were compared with C. acutatum “Herb IMI 232176” (1). C. gloeosporioides cultures were dark gray; their reverse was dark mouse gray to fuscous black. The cirrhus was peach to orange and hyaline conidia were oblong with rounded ends measuring 8.6 to 13.40 × 2.68 to 4.02 μm. Pathogenicity was verified on greenhouse-grown tulip trees and strawberry cv. Pájaro (Fragaria × ananassa) by spray inoculation with conidial suspensions of C. acutatum (107/ml), C. gloeosporioides (106/ml), and a mixture of both species (equal parts of each suspension). Controls were sprayed with sterile distilled water. Irregular, blotchy lesions of tulip tree appeared 30 days after inoculation. Anthracnose symptoms (3) were observed on strawberries 7 days after inoculation. In all cases, lesions produced by the mixture were larger than those obtained with individual species. The inoculated fungi were reisolated from lesions of all species tested, fulfilling Koch's postulates. No lesions were observed on control plants. Voucher specimens were deposited in La Plata Spegazzini Herbarium, Argentina as C. acutatum (LPS 47187) and C. gloeosporioides (LPS 47188); cultures of both fungi were also deposited as LPSC 795 and LPSC 796, respectively. C. acutatum and C. gloeosporioides cause Liriodendron leaf blotch in Argentina. Glomerella cingulata was previously reported affecting L. tulipifera (2), but to our knowledge, this is the first report of tulip tree as a host of C. acutatum.

References: (1) B. J. Dyko and J. E. M. Mordue. No. 630 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1979 (2) K. Ito and T. Kobayashi. Bull. For. Exp. Stn. Meguro 146:1, 1962. (3) C. J. Ramallo et al. Plant Dis. 84:706, 2000. (4) J. A. von Arx. Phytopathol. Z. 29:413, 1957.
First Report of Fire Blight Caused by Erwinia amylovora on Pyracantha coccinea in Bulgaria
Authors: Bobev S. G. , Baeyen S. , Crepel C. , Maes M.
Published: May 2007

During late May and June of 2003, a fire blight epidemic occurred in southcentral Bulgaria on earlier reported hosts such as apple, pear, quince, and hawthorn (1). A new host was found when fire blight was also observed in mid-June on Pyracantha coccinea grown in the Plovdiv Region. Symptoms were necrotic flowers, shoots, petioles, and the presence of sticky ooze droplets mainly on the shoots. Isolations made from blighted Pyracantha coccinea flowers and shoots onto King's medium B (2 days at 25 to 26°C) yielded whitish, glistening, round bacterial colonies. Infiltration of the suspensions of three of the isolates into tobacco leaves resulted in a typical hypersensitive reaction. When Pyracantha coccinea and Cotoneaster sp. shoots were inoculated with these three isolates, typical fire blight symptoms were obtained. The pathogen was reisolated 2 weeks after inoculation from necrotic tissues (15 to 20 mm above and below the inoculation site), thereby fulfilling the Koch's postulates. No symptoms and bacteria were found within any of the shoots from the same plant species injected with sterile water. The identity of the isolates was also determined by conducting nested polymerase chain reaction (PCR) (2) and target-specific PCR (23S rDNA) (3). On the basis of the symptoms, cultural characteristics, and positive results in pathogenicity and PCR tests, the isolates were considered to be Erwinia amylovora. To our knowledge, this is the first report of fire blight on Pyracantha coccinea in Bulgaria.

References: (1) S. G. Bobev et al. Plant Dis. 82:1283, 1998. (2) P. Llop et al. Appl. Environ. Microbiol. 66:2071, 2000. (3) M. Maes et al. Plant Pathol. 45:1139, 1996.
Genes for Parasite-Specific, Nonhost Resistance in Populus
Authors: Newcombe George
Published: May 2007

Nonhost resistance is hypothesized to protect plants in a nonspecific manner. For highly specialized parasites, this hypothesis applies not only to distantly related plants but also to resistant congeners of the host species. Congeners of Populus spp. were hybridized to create two interspecific hybrid poplar pedigrees (i.e., Populus trichocarpa × P. deltoides and P. trichocarpa × P. maximowiczii). The pedigrees were planted in a randomized, replicated “common garden” on Vancouver Island so that they were exposed to parasites of the native P. trichocarpa. Monogenic and oligogenic resistance to two ascomycetous, parasitic fungi (i.e., Venturia inopina and a Taphrina sp.) segregated in a parasite-specific manner in each pedigree. However, these resistance genes were not inherited from the native host, P. trichocarpa. Instead, resistance was inherited from the allopatric, nonhost congeners, P. deltoides (eastern cottonwood) and P. maximowiczii (Japanese poplar). Thus, we found that major genes condition parasite-specific, nonhost resistance, as has been true in earlier studies of this kind with additional parasites of Populus spp. The selective force responsible for evolutionary maintenance of such genes is unknown.
Influence of Environmental Conditions on Spore Production and Budding in Taphrina deformans, the Causal Agent of Peach Leaf Curl
Authors: Rossi V. , Languasco L.
Published: May 2007

Environment-controlled studies were carried out to determine the growth of Taphrina deformans under different conditions of temperature, humidity, and nutrient availability similar to those found on plant surfaces during the peach-growing season. Both ascospores and blastospores were able to bud at all temperatures tested (5 to 37°C), with the optimum at 14 and 21°C, respectively. Temperature <20°C favored ascospore production and release, with the optimum at 10°C. Budding was approximately two-and-a-half times higher in a film of water than on a dry substrate, with 100% relative humidity and blastospores also maintained a certain budding ability at lower humidity levels (minimum tested = 47%). Both spore types did not bud after ≈50 to 55 h in the absence of external nutrients. In the presence of a periodically renewed carbon source, such as simple sugars, at concentrations that typically are present on peach plant surfaces, the fungus maintained its budding capability over time. Results showed that T. deformans is able to bud profusely under a wide range of environmental conditions that occur on peach tree surfaces. This work supports the hypothesis that T. deformans is a part of the normal epiphytic mycoflora of peach trees throughout the entire growing season.
Interspecific Hybridization of Meiotic Parthenogenetic Meloidogyne chitwoodi and M. fallax
Authors: van der Beek J. G. , Karssen G.
Published: May 2007

Hybridization between two meiotic parthenogenetic species of root-knot nematodes, Meloidogyne chitwoodi and M. fallax, was investigated in two different crossing experiments on tomato plants grown in sand. The first experiment was a controlled cross between the two species. The second experiment was a bulk mating in a 1:1 mixture of two isolates. The haploid chromosome number of the parental isolates was n = 18. Successful interspecific hybridization was obtained, and the resulting hybrids produced egg masses. In eggs, cell division was observed, but most of them were without clear differentiation and consequently were sterile. Hatched F2 juveniles were small in number, not viable, and showed morphological distortions. In the progeny of the isolate mixture of the bulk mating experiment, parental-type females of the two isolates were present in equal numbers, and 10% of all females were nonviable hybrids. Similar ratios of parental-type and hybrid females were detected in roots of test plants grown in soil from a field sample that contained a mixture of M. chitwoodi and M. fallax populations. In the controlled cross experiment, isozyme electrophoresis of malate dehydrogenase was applied to distinguish the two species and their hybrids. In the bulk mating experiment, malate dehydrogenase, esterase, and glucose 6-phosphate dehydrogenase were used as markers, two by two simultaneously on the same individual females, providing conclusive evidence for the occurrence of hybrids. This is the first report on interspecific hybridization in Meloidogyne. The possible role of interspecific hybridization in species differentiation and interspecific exchange of genetic material within Meloidogyne is discussed.
Comparison of Ethylene Production by Pseudomonas syringae and Ralstonia solanacearum
Authors: Weingart H. , Völksch B. , Ullrich M. S.
Published: May 2007

Strains of Pseudomonas syringae pv. pisi and Ralstonia solanacearum produced ethylene at rates 20- and 200-fold lower, respectively, than strains of P. syringae pvs. cannabina, glycinea, phaseolicola, and sesami. In the current study, we investigated which ethylene biosynthetic pathways were used by P. syringae pv. pisi and R. solanacearum. Neither the activity of an ethylene-forming enzyme nor a corresponding efe gene homolog could be detected in R. solanacearum, suggesting synthesis of ethylene via 2-keto-4-methyl-thiobutyric acid. In contrast, 2-oxoglutarate-dependent ethylene formation was observed with P. syringae pv. pisi, and Southern blot hybridization revealed the presence of an efe homolog in this pathovar. The efe genes from P. syringae pvs. cannabina, glycinea, phaseolicola, pisi, and sesami were sequenced. Nucleotide sequence comparisons indicated that the efe gene in pv. pisi was not as highly conserved as it was in other P. syringae pathovars. The pv. pisi efe homolog showed numerous nucleotide substitutions and a deletion of 13 amino acids at the C-terminus of the predicted gene product. These sequence alterations might account for the lower rate of ethylene production by this pathovar. All ethylene-producing P. syringae pathovars were virulent on bush bean plants. The overlapping host range of these pathovars suggests that horizontal transfer of the efe gene may have occurred among bacteria inhabiting the same host.
Influence of a Fungus-Feeding Nematode on Growth and Biocontrol Efficacy of Trichoderma harzianum
Authors: Bae Yeoung-Seuk , Knudsen Guy R.
Published: May 2007

A fungivorous nematode, Aphelenchoides sp., was isolated from field soil by baiting with mycelium of the biocontrol fungus Trichoderma harzianum ThzID1, and subsequently was maintained on agar cultures of the fungus. Interactions between the nematode and the green fluorescent protein-producing transformant, T. harzianum ThzID1-M3, were investigated in both heat-treated (80°C, 30 min) and untreated field soil. ThzID1-M3 was identified in soil by epifluorescence microscopy. When ThzID1-M3 was added to soil as an alginate pellet formulation, addition of the nematode (10 per gram of soil) significantly reduced radial growth and recoverable populations of the fungus, and the effect was greater in heat-treated soil than in untreated soil. Addition of ThzID1-M3 to soil pretreated with the nematode (10 per gram of soil) stimulated nematode population growth for approximately 10 to 20 days, whereas nematode populations decreased in the absence of added Trichoderma sp. When sclerotia of Sclerotinia sclerotiorum were added to soil (10 per 200 g of soil) with ThzID1-M3 (40 pellets per 200 g of soil), addition of Aphe-lenchoides sp. (2,000 per 200 g of soil) reduced the number of sclerotia colonized by ThzID1-M3. These results suggest that fungivorous nematodes may be a significant biotic constraint on activity of biocontrol fungi in the field.
Surfactant Protein B Detection and Gene Expression in Chronic Rhinosinusitis
Authors: Woodworth Bradford A. , Wood Rachel , Bhargave Geeta , Cohen Noam A. , Baatz John E. , Schlosser Rodney J.
Published: May 2007

Introduction: Surfactant protein (SP)‐B is a hydrophobic protein secreted within pulmonary surfactant that facilitates the adsorption of surface‐active lipids to the air‐liquid interface of the alveoli and increases alveolar stability. SP‐B may also have anti‐inflammatory properties. It is implicated in decreasing the pulmonary inflammatory response to bacterial lipopolysaccharide. However, the expression and function of SP‐B in the sinonasal cavities has not been elucidated. Our objective was to detect the presence of SP‐B, measure alterations in several forms of chronic rhinosinusitis (CRS), and localize cellular protein expression.

Materials/Methods: Sinus mucosal biopsies were performed in patients with allergic fungal rhinosinusitis (AFRS), nonatopic CRS with nasal polyposis (NP), and cystic fibrosis (CF) and in healthy controls. SP‐B mRNA was measured in CRS and control patients using quantitative polymerase chain reaction. Immunoblot analysis and immunolocalization of SP‐B were also performed.

Results: CF (n = 4) showed significantly increased levels of SP‐B (169‐fold) mRNA (P = .004) when compared with controls (n = 5). CRS with NP (n = 5) and AFRS (n = 7) also demonstrated elevated levels of SP‐ B (14‐fold and 4‐fold, respectively) when compared with the control group, although these were not statistically significant. Immunoblot analysis confirmed the presence of the translated product, and immunolocalization revealed expression in the epithelium and submucosal glandular elements.

Conclusion: This is the first study to detect and characterize SP‐B in human sinus mucosa. Furthermore, SP‐B is significantly up‐regulated in CF CRS.
A Novel Drug Therapy for Recurrent Laryngeal Nerve Injury Using T‐588
Authors: Mori Yuko , Shiotani Akihiro , Saito Koichiro , Araki Koji , Ikeda Ken , Nakagawa Masaya , Watabe Kazuhiko , Ogawa Kaoru
Published: May 2007

Objectives/Hypothesis: We have previously shown that gene therapy using Insulin‐like growth factor (IGF)‐I, glial cell line‐derived neurotrophic factor (GDNF), and brain‐derived neurotrophic factor (BDNF), or a combination of these trophic factors, is a treatment option for recurrent laryngeal nerve (RLN) palsy. However, there remain some difficulties preventing this option from becoming a common clinical therapy for RLN injury. Thus, we need to develop novel treatment option that overcomes the problems of gene therapy.

R(—)‐1‐(benzothiophen‐5‐yl)‐2‐[2‐N,N‐diethylamino]ethoxy]ethanol hydrochloride (T‐588), a synthetic compound, is known to have neuroprotective effects on neural cells. In the present study, the possibility of new drug treatments using T‐588 for RLN injury was assessed using rat models.

Study Design: Animal study.

Methods: Animals were administered T‐588 for 4 weeks. The neuroprotective effects of T‐588 administration after vagal nerve avulsion and neurofunctional recovery after recurrent laryngeal nerve crush were studied using motoneuron cell counting, evaluation of choline acetyltransferase immunoreactivity, the electrophysiologic examination, and the re‐mobilization of the vocal fold.

Results: T‐588 administration successfully prevented motoneuron loss and ameliorated the choline acetyltransferase immunoreactivity in the ipsilateral nucleus ambiguus after vagal nerve avulsion. Significant improvements of motor nerve conduction velocity of the RLN and vocal fold movement were observed in the treatment group when compared to controls.

Conclusion: These results indicate that oral administration of T‐588 might be a promising therapeutic option in treating peripheral nerve injury.
Time is of the essence: exploring a measles outbreak response vaccination in Niamey, Niger
Authors: Grais R.F , Conlan A.J.K , Ferrari M.J , Djibo A , Le Menach A , Bjørnstad O.N , Grenfell B.T
Published: May 2007

The current World Health Organization recommendations for response during measles epidemics focus on case management rather than outbreak response vaccination (ORV) campaigns, which may occur too late to impact morbidity and mortality and have a high cost per case prevented. Here, we explore the potential impact of an ORV campaign conducted during the 2003–2004 measles epidemic in Niamey, Niger. We measured the impact of this intervention and also the potential impact of alternative strategies. Using a unique geographical, epidemiologic and demographic dataset collected during the epidemic, we developed an individual-based simulation model. We estimate that a median of 7.6% [4.9–8.9] of cases were potentially averted as a result of the outbreak response, which vaccinated approximately 57% (84 563 of an estimated 148 600) of children in the target age range (6–59 months), 23 weeks after the epidemic started. We found that intervening early (up to 60 days after the start of the epidemic) and expanding the age range to all children aged 6 months to 15 years may lead to a much larger (up to 90%) reduction in the number of cases in a West African urban setting like Niamey. Our results suggest that intervening earlier even with lower target coverage (approx. 60%), but a wider age range, may be more effective than intervening later with high coverage (more than 90%) in similar settings. This has important implications for the implementation of reactive vaccination interventions as they can be highly effective if the response is fast with respect to the spread of the epidemic.
Scattering from laterally heterogeneous vesicles. II. The form factor
Authors: Anghel Vinicius N. P. , Kučerka Norbert , Pencer Jeremy , Katsaras John
Published: May 2007

Despite growing interest in the formation of domains or `rafts' in cell and model membranes, there have been relatively few attempts to characterize such systemsviascattering techniques. Previously [Penceret al.(2006).J. Appl. Cryst.39, 293–303], it was demonstrated that the Porod invariant,Q, could be used to detect lateral segregation. Here, the general theory for scattering from laterally heterogeneous vesicles is outlined and form factors are derived for vesicles containing either single circular or annular domains. These form factors are then applied to the analysis of neutron scattering data from heterogeneous vesicles. Potential advantages and limitations of this technique are also discussed.
Synchrotron powder diffraction in a systematic study of 4′-[2-(tosylamino)benzylideneamino]-2,3-benzo-15-crown-5 complexes
Authors: Dorokhov Andrey V. , Chernyshov Dmitrii Yu. , Burlov Anatolii S. , Garnovskii Alexandr D. , Ivanova Irina S. , Pyatova Elena N. , Tsivadze Aslan Yu. , Aslanov Leonid A. , Chernyshev Vladimir V.
Published: May 2007

The crystal structures of two compounds, CuL
2 and LiNCS·HL [HL = 4′-[2-(tosylamino)benzylideneamino]-2,3-benzo-15-crown-5], have been determined from synchrotron powder diffraction data. Both compounds crystallize in the monoclinic space group P2
1/c and with one molecule in the asymmetric unit. In CuL
2 the four N atoms of two bidentate L ligands coordinate the CuII ion in a distorted tetrahedral geometry with Cu—N distances of 1.98 (5)–2.05 (5) Å, while two O atoms from two sulfoxide groups complete the distorted octahedral Cu coordination [Cu—O 2.64 (4), 2.74 (4) Å]. In LiNCS·HL, lithium is coordinated by all five ether O atoms with Li—O distances of 2.03 (3)–2.50 (3) Å and an N atom from the thiocyanate moiety [Li—N 1.98 (3) Å] in a distorted pentagonal pyramidal geometry. Preliminary potentiometric selectivity measurements for ion-selective electrodes (ISEs) based on CuL
2 and ZnL
2 demonstrated significant differences in their selectivity. In order to find a possible reason for this, theoretical calculations at the DFT (B3LYP) level were performed. These calculations used the crystal structures of CuL
2, LiNCS·HL, ZnL
2 and HL as input geometries for the minimum energy optimization in vacuo. The results indicate that in ML
2 complexes (M = Cu, Zn) the electronic structure of the metal ion determines the spatial orientation of benzo-15-crown-5 macrocycles, and their different orientation in CuL
2 and ZnL
2 results in different potentiometric selectivities of ISEs based on these compounds.
Solid-state compounds of stereoisomers: cis and trans isomers of 1,2-cyclohexanediol and 2,3-tetralindiol
Authors: Lloyd Michael A. , Patterson Garth E. , Simpson Greg H. , Duncan Laura L. , King Daniel P. , Fu Yigang , Patrick Brian O. , Parkin Sean , Brock Carolyn Pratt
Published: May 2007

The phases of 1,2,3,4-tetrahydro-2,3-naphthalenediol (or 2,3-tetralindiol) and of 1,2-cyclohexanediol have been investigated. The structure of a very stable 1:1 compound (or co-crystal) of the cis and trans isomers of 2,3-tetralindiol, the existence of which has been known for nearly a century, has finally been determined. No evidence of any analogous compound between the cis and trans isomers of 1,2-cyclohexanediol has been found. The formation of solid-state compounds of stereoisomers is rare; it probably occurs only if the crystal packing of at least one of the isomers is unfavorable, e.g. if at least one of the melting points is lower than expected. Compound formation is usually unlikely because of the difficulty of simultaneously optimizing the translational spacings for both isomers, but that packing problem is avoided in the cis/trans compound of 2,3-tetralindiol because the two isomers are in very similar environments. In the structures of the individual 2,3-tetralindiol isomers there are clear conflicts between the competing packing requirements of the 1,2-diol moiety and the aromatic ring system; these conflicts are resolved better in the co-crystal than in the structures of the individual isomers.
Structures of artificial sweeteners – cyclamic acid and sodium cyclamate with other cyclamates
Authors: Leban Ivan , Rudan-Tasič Darja , Lah Nina , Klofutar Cveto
Published: May 2007

In the course of a study on artificial sweeteners, new crystal structures of cyclamic acid, sodium cyclamate, potassium cyclamate, ammonium cyclamate, rubidium cyclamate and tetra-n-propylammonium cyclamate have been determined. Cyclamic acid exists in its zwitterionic form in the crystalline state. The zwitterions are connected through hydrogen bonds of the N—H...O type to form two-dimensional sheets. The sodium, potassium, ammonium and rubidium cyclamates are isostructural, with the cyclamate moieties linked through hydrogen bonds into linear chains. Taking into account the connectivity through cations, two-dimensional layers with a hydrophobic surface are constructed. In tetra(n-propyl)ammonium cyclamate the large, non-coordinating cation apparently prevents the formation of chains and thereby facilitates the centrosymmetric head-to-head discrete dimeric arrangement of the cyclamate moieties.