bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a New, Monopartite Begomovirus Associated with Leaf Curl Disease of Cotton in Gezira, Sudan
Authors: Idris A. M. , Brown J. K. 
Published: May 2007

Cotton leaf curl disease (CLCuD) was first reported in Sudan in 1931. Disease symptoms in cotton were characterized by vein thickening and leaf curling, and the suspect causal agent was shown to be transmitted by the whitefly Bemisia tabaci (Genn.) among cotton, okra, and several weed species (2). Although begomovirus etiology was suspected based on symptomatology and vector transmission, no evidence was available that confirmed or disputed this hypothesis. During 1994 to 1996, four cotton samples exhibiting typical CLCuD symptoms were collected from different fields in the Gezira region in Central Sudan and examined for presence of begomovirus DNA. Total nucleic acids were isolated from cotton plants and subjected to polymerase chain reaction (PCR) using degenerate primers (pAV 2644 and pAC 1154) to amplify begomovirus coat protein (Cp) gene and its flanking sequences (1). An amplicon of the expected size (1,300 bp) was obtained by PCR from each sample, and their nucleotide (nt) sequences were determined. Virus-specific primers designed around the Cp sequence were used to amplify an apparent full-length DNA component. Amplicons were cloned and their sequences were determined, yielding a begomoviral component of approximately 2,761 nt (AF260241). Despite exhaustive attempts to amplify a putative viral B-component using degenerate primers based on the intergenic region sequence of the putative “A-component,” or sequences that are highly conserved for other begomoviruses, no B component was detected. The four cotton isolates shared 99.9 to 100% nt sequence identity, and the number and arrangement of predicted open reading frames were similar to those known for other monopartite begomoviruses. Phylogenetic analysis of the putative CLCuV genome with other begomoviruses indicated that its closest relative was Althea rosea enation virus (AREV) from Egypt (AF014881) with which it shares 79% sequence identity, indicating that CLCuV is a unique begomovirus species with a probable origin in the Eastern Hemisphere. CLCuV shared 66% identity with its second closest relative, Cotton leaf curl virus-Pakistan (CLCuV-PK) (AJ002448). These data provide the first direct evidence for the association of a monopartite begomovirus with the leaf curl disease of cotton in Gezira, Sudan, that is distinct from all other begomoviral species described to date. Herein, we provisionally designate this unique begomoviral species as Cotton leaf curl virus from Sudan (CLCuV-SD). References: (1) A. M. Idris and J. K. Brown. Phytopathology 88:648, 1998. (2) A. M. Nour and J. J. Nour. Emp. Cott. Gr. Rev. 41:27, 1964.
Puccinia sorghi in Sinaloa, Mexico Virulent on Corn with the Rp1-D Gene
Authors: Pataky J. K. , Natti T. A. , Snyder E. B. , Kurowski C. J. 
Published: May 2007

Several different Rp genes in corn condition chlorotic fleck resistant reactions to Puccinia sorghi. Rp-resistance has been used successfully for the past 15 years to control common rust on sweet corn in North America. Most, but not all, Rp-resistant sweet corn hybrids carry the Rp1-D gene. In August and September 1999, isolates of P. sorghi were collected from Rp-resistant sweet corn grown in Illinois, Wisconsin, Minnesota, Michigan, and New York. This was the first widespread occurrence in North America of P. sorghi virulent on corn with Rp1-D (2). The origin of this population of P. sorghi with a virulence phenotype new to North America is not known. Since many believe Mexico is the source of common rust inocula for the midwestern United States, it is important to discover if this virulence occurs in Mexico. Forty-one Rp-resistant and nine susceptible sweet corn hybrids were planted 8 December 1999 in a nursery near Los Mochis, Mexico, in the state of Sinalao. Rp-resistant hybrids had been effective against common rust in Los Mochis nurseries prior to 1999. Each hybrid was in a single row of about 30 plants. The Los Mochis nursery also included two replicate rows of sweet corn or field corn inbred lines with one of 17 different single Rp-genes or one of 11 different compound genes for rust resistance (1). Plants were exposed to local populations of P. sorghi. Reactions were rated in March 2000. Sporulating uredinia (susceptible reactions) were abundant on all sweet corn hybrids and on inbreds with Rp1-D. Susceptible reactions also were observed on other inbred lines with Rp-genes except for lines with the single genes: Rp1-E, Rp-G, Rp1-I, Rp1-K, and Rp1-L or lines with the compound rust genes: Rp1-GI, Rp1-G5, Rp1-GDJ, Rp1-GFJ, Rp1-G5JC, Rp1-G5JD, and Rp1-JFC. This pattern of virulence is similar to that of P. sorghi isolates collected in the midwestern United States in 1999. Rp-resistance currently available in most sweet corn hybrids grown in the Midwest will not be effective when this population of P. sorghi spreads from Mexico to the United States. Therefore, other sources of rust resistance need to be incorporated into sweet corn hybrids. References: (1) S. H. Hulbert, Annu. Rev. Phytopathol. 35:292, 1997. (2) J. K. Pataky and W. F. Tracy. Plant Dis. 83:1177, 1999.
First Report of Tomato yellow leaf curl virus-Is (TYLCV-Is) in the Canary Islands
Authors: Font I. , Martínez-Culebras P. , Jordá C. 
Published: May 2007

In autumn of 1999 and winter-spring 2000, tomato (Lycopersicon) crops grown in the Regions of Las Palmas de Gran Canaria and Tenerife (Canary Islands) showed upward curling of leaves, yellowing of leaf margins, crumpling of new leaves, reduction of leaflet area, and stunting of shoots. These symptoms were similar to those described for tomato yellow leaf curl disease. Symptomatic samples were collected from Las Palmas de Gran Canaria (33 samples) and Tenerife (45 samples) for polymerase chain reaction (PCR) identification analysis. The degenerate primers pair of Begomovirus (AV494/AC1048) (3) was used to amplify the “core” region of the capsid protein gene. Two tomato plants experimentally infected with Tomato yellow leaf curl virus-Is (TYLCVIs) or TYLCV-Sar served as positive controls. Electrophoretic analysis of all samples showed a single fragment of the expected size (550 bp). To identify the type of TYLCV (TYLCV-Sar or TYLCV-Is), the PCR products were digested by endonucleases (AluI, HaeIII, HpaII, RsaI, Sau3A, TaqI, DdeI, and ScrFI). Twenty-six samples from Las Palmas de Gran Canaria showed the same restriction pattern of TYLCV-Sar, and seven samples from Las Palmas de Gran Canaria and all 45 samples from Tenerife showed the same restriction pattern of TYLCV-Is. These results confirm that TYLCV-Sar and TYLCV-Is are present in Las Palmas de Gran Canaria and TYLCV-Is is present in Tenerife. The presence of TYLCV-Is in Morocco (2) and TYLCV-Sar in the Canary Islands and Morocco has been recently described (1). However, this is the first report of TYLCV-Is in the Canary Islands. References: (1) F. Monci et al. Plant Dis. 84:490, 2000. (2) M. Peterschmitt et al. Plant Dis. 83:1074, 1999. (3) S. D. Wyatt et al. Phytopathology 86:1288, 1996.
First Report of Powdery Mildew Caused by Podosphaera (Sphaerotheca) fusca on Euryops pectinatus in North America
Authors: Saenz G. S. , Koike S. T. , Shishkoff N. 
Published: May 2007

Gray-leaved Euryops (Euryops pectinatus Cass., Asteraceae) is an evergreen shrub that is widely planted in landscapes in the United States. In the fall of 1999, powdery mildew was observed on E. pectinatus planted in landscapes in Redlands (San Bernardino County), CA. Symptoms consisted only of slight cupping of leaves. Fungal growth was observed on stems, leaves, petioles, and pedicels and was ectophytic and amphigenous. The white mycelium was patchy to effuse. Hyphal appressoria were indistinct (1). Conidiophore foot cells were cylindric and sometimes were tapered toward or constricted at the base. Foot cells measured 30 to 50 by 10 to 12 μm and were followed by one to two shorter cells. Conidia were cylindric to slightly doliform, borne in chains of two to three, and measured 26 to 38 by 14 to 18 μm. Conidial length to width ratios ranged from 1.7 to 2.4. Catenate conidia had crenate edge lines (3). Conidia possessed conspicuous fibrosin bodies and from their sides produced short germ tubes without appressoria. Cleistothecia were not observed. Based on these characters, the fungus was identified as Podosphaera fusca (Fr.) U. Braun & N. Shishkoff (Podosphaera sect. Sphaerotheca) (1,2). Pathogenicity was confirmed by gently pressing diseased leaves onto leaves of healthy E. pectinatus plants. Plants were incubated in a humidity chamber at 22 to 24°C and after 12 to 14 days powdery mildew colonies developed. E. pectinatus cv. Viridis, a cultivar that lacks the extensive pubescence of E. pectinatus, also developed disease when inoculated. This appears to be the first report of powdery mildew on E. pectinatus in North America. A voucher specimen has been deposited into the University of California Herbarium (accession # UC1738635). P. fusca was also observed on cv. Viridis in a nursery in New York in 1999. It is unclear where this pathogen originated. P. fusca parasitizes a large number of asteraceous species including dandelion (Taraxacum officinalis) and sowthistle (Sonchus spp.) weeds, which occur in the area and sometimes are infected with powdery mildew. The Euryops powdery mildew pathogen may be a race that is different than those found on other composites in the United States. The fungus was observed on plants in shaded areas but not on plants in full sun. References: (1) U. Braun. Nova Hedwigia 89:1, 1987. (2) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (3) H. D. Shin and Y. J. La. Mycotaxon 46:445, 1993.
First Report of Occurrence of Sclerotinia Blight on Petunia in Louisiana
Authors: Holcomb G. E. 
Published: May 2007

Petunia × hybrida Wave series cultivars were observed with symptoms of tan to brown stem lesions, wilt, and branch death in a demonstration/trial planting at Burden Research Center in Baton Rouge, LA, during January and February 2000. Disease signs included the presence of white, cottony mycelia on infected stems and the presence of black sclerotia. Seventeen of 131 plants were infected on 20 February and included individuals of cvs. Wave Purple, Wave Rose, Wave Misty Lilac, Wave Pink, Tidal Wave Hot Pink, and Tidal Wave Cherry. Isolations were made by placing diseased stem sections on acidified potato-dextrose agar. A fungus that produced white mycelia and black sclerotia was consistently isolated from infected stems and identified as Sclerotinia sclerotiorum. Pathogenicity tests were done by pipetting 1 to 2 ml of blended mycelia and sclerotia (one plate culture blended in 100 ml distilled water) at the base of flowering-age Wave series plants. Plants were held for 3 days in a dew chamber maintained at 22°C and then moved to a greenhouse held at 25°C. Wilt and branch death developed on inoculated plants after 5 days and S. sclerotiorum was reisolated. Uninoculated plants remained healthy. Wave series cultivars have a prostrate growth habit that is conducive to disease development. No plants in the trial planting were killed and infected plants had recovered by 1 May and had uniformly covered the plant bed. Sclerotinia blight was previously reported on Petunia × hybrida from Bermuda (2) and Florida (1). References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) J. M. Waterston. Dept. Agric. Bermuda Rep., 1947.
Occurrence of a Reovirus Infecting Maize in India
Authors: Lenardon S. L. , Giolitti F. , Welz H. G. , Verma P. 
Published: May 2007

During the 1998-99 season, maize plants showing viruslike symptoms were observed at two locations in the Andhra Pradesh state in Southern India. Several hybrids were evaluated at Hyderabad in a replicated yield trial and most were affected, with disease incidence ranging from 4.4 to 61.8% of the plants among plots. Hybrid 4642 (Proagro 3-way hybrid, late maturity) and the pre-commercial hybrid YLY102 were the most susceptible, whereas the popular hybrid 4640 was among the least susceptible entries. In seed production fields near Eluru, incidence ranged from 10 to 15% among plots, with the female parent of hybrid 4210 (Proagro 3-way hybrid, early maturity) being especially affected. Symptoms observed in hybrids varied, presumably, according to the infection time and included severe plant dwarfing, dark-green leaves, enations on the lower leaf surface, and small malformed ears with few or no kernels. Symptomatic and asymptomatic field plants (root and leaf tissues) were tested by ds-RNA polyacrylamide gel electrophoresis and by double-antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) with antiserum to Mal de río cuarto virus (MRCV), a Reoviridae-Fijivirus member. MRCV and Maize rough dwarf virus (MRDV) were selected as controls because the symptoms were similar to those caused by these maize viruses (1,2). ds-RNA gels from symptomatic plants showed 10 bands with banding patterns different from those of MRCV or MRDV. DAS-ELISA indicated a distant relationship to MRCV. These results provide evidence of a reovirus infection to maize hybrids in India and suggest that a virus belonging to the family Reoviridae, genus Fijivirus is causing this new disease. The high disease incidence and the severity of symptoms should alert breeders and pathologists in southern Asia about potential yield losses. References: (1) G. Boccardo and R. G. Milne. 1984. Descriptions of Plant Viruses 294. Inst. Hortic. Res., Wellesbourne. (2) C. Marzachi et al. J. Plant Dis. Prot. 106:431–436, 1999.
First Report of Broad bean wilt virus on Thyme (Thymus vulgaris L.)
Authors: Bellardi M. G. , Rubies-Autonell C. 
Published: May 2007

In the spring and summer of 1998, a severe virus-like disease consisting of chlorotic mottle on leaves, yellowing, and stunting was observed at the Giardino delle Erbe of Casola-Valsenio (Emila-Romagna region, northern Italy). Most of the symptomatic plants were infected with a filamentous virus that was not identified. Moreover, one thyme plant showing yellow leaves was also found infected by an isometric virus, the identity of which was established by the following host reactions and serological assay. It was mechanically transmitted to 33 species belonging to 11 botanical families. All the Chenopodiaceae (Chenopodium amaranticolor Coste et Reyn., C. murale L., C. foliosum Ash., and C. quinoa Willd.) tested showed local and systemic symptoms in 3 to 4 days; among Leguminosae, broad bean (Vicia faba L.) showed necrotic local lesions and wilt. Virus particles reacted in protein A sandwich-enzyme-linked immunosorbent assay with the antiserum to Broad bean wilt virus (BBWV), serotype I (supplied from the Istituto di Fitovirologia Applicata, CNR, Turin, Italy). BBWV in the field was in all probability transmitted to thyme by aphids from weeds and/or other medicinal and aromatic species cultivated in the same herb garden, all recently shown to be hosts for BBWV: Polygonum fagopyrum L., Hedisarum coronarium L., Borago officinalis L., Phytolacca Americana L., Digitalis lanata Ehrh., and D. purpurea L. (1). This is the first report of BBWV in T. vulgaris and demonstrates that it is more prevalent in Italy than previously reported. References: (1) C. Rubies-Autonell and M. G. Bellardi. 1999. 7th International Plant Virus Epidemiology Symposium, Aguadulce, Spain.
First Report and Partial Molecular Characterization of a New Begomovirus Associated with Pigeon Pea in Puerto Rico
Authors: Rodriguez R. L. , Hong S. , Maxwell D. P. 
Published: May 2007

Pigeon pea (Cajanus cajan (L.) Millsp.) is an important edible legume crop in Puerto Rico. In late fall 1997, symptoms of a golden mosaic virus were observed in a pigeon pea planting in the municipality of Villalba. The symptoms resembled those incited by the Rhynchosia mosaic virus, a whitefly-transmitted virus, in pigeon pea (1). Tests with the 3F7 antigeminivirus antibody from Agdia (Elkhart, IN) confirmed the presence of a begomovirus in these symptomatic pigeon peas. Extraction of DNA from dried symptomatic foliar tissue was accomplished by the methods described in Rojas et al. (2), and subsequent viral DNA amplification was accomplished with the coat protein (CP) gene polymerase chain reaction primer pair AV494-AC1048 (3). A 550-bp fragment was cloned and sequenced (GenBank Accession No. AY028308). For sequence analysis, the BLAST program at the National Institutes of Health was used. The first match was 91% with the CP gene sequence (Accession No. AF070924) of a begomovirus from Clitoria falcata from Puerto Rico. The next three matches were approximately 86% with a begomovirus (accession no. AF058024) from Macroptilium lathyroides from Puerto Rico, Dicliptera yellow mottle virus (Accession No. AF139168) from Florida, and Tobacco apical stunt virus (Accession No. AF076855) from Mexico. On the basis of sequence analysis of this conserved region of the CP gene, it is concluded that the virus described in this report is a new virus, and thus named Pigeon pea golden mosaic virus. The only sequence for a begomovirus from a Rhynchosia sp. in GenBank is Rhynchosia golden mosaic virus from Honduras (accession no. AF239671). On the basis of sequence comparisons, the virus from pigeon pea is not an isolate of the Honduran Rhynchosia golden mosaic virus. References: (1) J. Bird et al. 1975. Pages 3–25 in: Tropical Diseases of Legumes. J. Bird and K. Maramorosch, eds. Academic Press, NY. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993. (3) S. D. Wyatt and J. K. Brown. Phytopathology. 86:1288, 1996.
First Report of Fusarium Wilt of Exacum affine Caused by Fusarium oxysporum
Authors: Elmer W. , O'Dowd E. 
Published: May 2007

Wilting Persian violets (Exacum affine) were observed in a Connecticut retail outlet. Diseased stems developed a dark coloration at the nodes, while the foliage turned papery, whitish tan. The vascular tissue in affected stems was reddish brown and extended from the base of the stem upward in a unilateral pattern. Fusarium grew from the discolored stem tissue when placed on Komada's medium (2). Single spores were cultured on carnation leaf agar and identified as F. oxysporum (2). Koch's postulates were completed by growing 12 2-month-old seedlings of E. affine ‘Midget’ in potting mix amended with ground dried millet seed (2.0 g/liter of soil) that had been colonized for 2 weeks by the fungus. Symptoms appeared slowly after 8 weeks, and F. oxysporum was re-isolated from the vascular tissue. Plants grown in soil mix with sterile millet remained healthy. Similar tests at different times of the year produced the same results. Other tests examined host specificity with two new isolates on seedlings of Persian violet, carnation, lisianthus, and basil. Both isolates caused symptoms only on Persian violets. Although Haematonectria haematococca (synonym Nectria haematococca, anamorph F. solani) causes Nectria canker of Persian violet (1), this is the first report of F. oxysporum causing Fusarium wilt of Persian violet. We propose the formae specialis be F. oxysporum f. sp. exaci. An isolate has been deposited at the Fusarium Research Center at The Pennsylvania State University, University Park, under Accession No. O-2282. References: (1) M. Daughtrey et al. Compendium of Flowering Potted Plant Diseases. American Phytopathological Society, St. Paul, MN, 1995. (2) Nelson et al. Fusarium species: An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, PA, 1983.
First Report of Sclerotinia sclerotiorum on Gazania sp. Hybrid in Italy
Authors: Garibaldi A. , Minuto A. , Gilardi G. , Gullino M. L. 
Published: May 2007

Gazania sp. hybrid is produced in pots in the Albenga Region of northern Italy for export to central and northern Europe. During fall 2000 to spring 2001, sudden wilt was observed in commercial plantings of this ornamental. Initial symptoms included stem necrosis at the soil level and yellowing and tan discoloration of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt followed by soft rot occurred within a few days on young plants after the first leaf symptoms. Necrotic tissues became covered with white mycelia that produced dark, spherical (2 to 6 mm diameter) sclerotia. Sclerotinia sclerotiorum was consistently recovered from infected stem pieces of Gazania disinfested for 1 min in 1% NaOCl, plated on potato dextrose agar amended with streptomycin sulfate at 100 mg/liter. Pathogenicity of three fungal isolates was confirmed by inoculating 45- to 60-day-old plants grown in containers (14 cm diameter). Inoculum that consisted of wheat kernels infested with mycelium and sclerotia of each isolate was placed on the soil surface around the base of each plant. Noninoculated plants served as controls. All plants were maintained outdoors where temperatures ranged between 8 and 15°C. Inoculated plants developed symptoms of leaf yellowing, followed by wilt, within 7 to 10 days, while control plants remained symptomless. White mycelia and sclerotia developed on infected tissues, and S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of wilt of Gazania sp. hybrid caused by S. sclerotiorum in Italy. A crown rot of Gazania caused by S. sclerotiorum has been reported from California in the United States(1). Reference: (1) V. M. Muir and A. H. McCain. Calif. Plant Pathol. 16:1, 1973.