bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of a 16SrI-B Group Phytoplasma Associated with a Yellows-Type Disease Affecting Tomato Plants in the Baja California Peninsula of Mexico
Authors: Holguín-Peña R. J. , Vázquez-Juárez R. C. , Martínez-Soriano J. P. 
Published: May 2007

Since 2000, a phytoplasma-like disease (locally known as “permanent yellowing”) was observed on tomatoes (Lycopersicon esculentum Mill.) grown in the Valle de San Quintín in northern Baja California Peninsula. Affected plants showed general chlorosis, severe stunting, upwardly rolled leaves, bronzing of mature leaves, purple discoloration of veins, “little leaf”, abnormal floral structures, and excessive branching of axillary shoots. Total DNA extracted from symptomatic and asymptomatic plants was used in nested (n)-PCR assays driven by phytoplasma-universal primer pair P1/P7 (3), followed by primer pair R16F2n/R16R2 (1) targeting the 16S ribosomal RNA gene of the putative phytoplasma. PCR conditions (direct and nested) were conducted as previously described (l,3). Restriction fragment length polymorphism (RFLP) patterns of nPCR-amplified products (≈ 1.25-kbp 16S rDNA fragments) digested with enzymes AluI, MseI, HhaI, and HpaII showed that 85% (17 of 20) of PCR-positive tomato samples had restriction patterns typical of phytoplasmas belonging to the aster yellows group, subgroup B (16SrI-B) “Candidatus Phytoplasma asteris” (2). Only 10% (2 of 20) of the samples were associated with a phytoplasma related to the 16SrXIII-A Mexican periwinkle virescence group (formerly group 16SrI, subgroup I). None of the symptomless plants tested positive. Subsequently, these results were confirmed by nPCR using 16SrI specific primer pair P1/Aint (4) and specific primers rp(I-B)F1/rp(I-B)R1 that amplify the ribosomal protein (rp) gene operon of aster yellows phytoplasma subgroup B (16SrI-B[rp-B]) (1). The presence of the phytoplasmas in symptomatic plants was confirmed by scanning electron microscopy. Characteristic yellow symptoms could be experimentally reproduced by graft inoculation of tomato seedlings (cv. Maya) with tissue of field-infected plants. Symptoms similar to those of field-grown diseased plants were observed consistently in most of the plants, and when graft transmitted from tomato to periwinkle (Catharantus roseus (L.) G. Don), symptoms of virescencent, small flowers were observed. In contrast, no symptoms were observed on plants grafted with tissues from healthy plants. In Baja California, it appears that at least two distinct phytoplasmas are involved in the disease complex. To our knowledge, this is the first molecular evidence of the presence of a phytoplasma associated with yellows-type diseases in the major tomato cultivation areas of the peninsula. References: (1) I.-M. Lee et al. Phytopathology 93:1368, 2003. (2) I.-M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:1037, 2004. (3) B. Schneider et al. Page 369 in: Molecular and Diagnostic Procedures in Mycoplasmology. Academic Press, San Diego, CA, 1995. (4) C. D. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996.
Xylella fastidiosa Detected in New Mexico in Chitalpa, a Common Landscape Ornamental Plant
Authors: Randall J. J. , Radionenko M. , French J. M. , Olsen M. W. , Goldberg N. P. , Hanson S. F. 
Published: May 2007

Different strains of Xylella fastidiosa cause a variety of significant disease problems in agricultural and ornamental plants, including Pierce's disease in grapes, oleander leaf scorch, pecan bacterial leaf scorch, and alfalfa dwarf disease. X. fastidiosa has never been reported in New Mexico but is known to exist in surrounding states (California, Arizona, and Texas). During the summer of 2006, several chitalpa (Chitalpa tashkinensis) hybrid trees with leaf scorch symptoms and branch die back were observed in Las Cruces, NM and they tested positive for X. fastidiosa by ELISA. Additional samples from these plants and others were analyzed by ELISA, PCR (2), and cultured on XfD2 medium (1). Known positive and negative oleander samples from Arizona were included as controls. Fifteen of thirty tested chitalpa were PCR and ELISA positive, indicating that they were infected with X. fastidiosa. Bacterial colonies that were PCR positive were also recovered from 10 of the XF positive samples that were plated. DNA sequences of PCR products amplified from chitalpa and isolated bacterial colonies (GenBank Accession Nos. EF109936 and EF109937) were identical to each other, 97% similar to X. fastidiosa strain JB-USNA, and 96% similar to the Temecula 1 strain. Independent ELISA testing (Barry Hill, California Department Food and Agriculture, Sacramento, CA) confirmed our ELISA and PCR results. On the basis of these results, we conclude that X. fastidiosa is present in New Mexico and that the common landscape ornamental chitalpa is a host for X. fastidiosa. Additional work is required to determine if X. fastidiosa is pathogenic to chitalpa and to examine the relevance of this potential X. fastidiosa reservoir to agricultural production in New Mexico and other areas where chitalpa is grown. References: (1) R. P. P. Almeida et al. Curr. Microbiol. 48:368, 2004. (2) M. R. Pooler et al. Lett. Appl. Microbiol. 25:123, 1997.
First Report of the Presence of Tomato apical stunt viroid on Tomato in Sénégal
Authors: Candresse T. , Marais A. , Ollivier F. , Verdin E. , Blancard D. 
Published: May 2007

Tomato apical stunt viroid (TASVd) was initially discovered in the Ivory Coast (2). It was later reported in Indonesia and more recently was found to be responsible for severe outbreaks in protected tomatoes in Israel (1) and Tunisia (3). Although not of quarantine status, TASVd is included in the EPPO alert list. In 2005, severe arrest of apical growth and leaf chlorosis were observed in tomato samples from northern Sénégal. Tomato yellow leaf curl virus was initially identified in some samples, but since the symptoms observed were reminiscent of those associated with viroid infection, samples were analyzed by return-polyacrylamide gel electrophoresis and molecular hybridization with a Potato spindle tuber viroid (PSTVd) probe. Positive results prompted a reanalysis by reverse transcription-PCR assays specific for PSTVd or TASVd. Positive amplification was only obtained with the TASVd-specific primers (Vir+ GGGGAAACCTGGAGGAA and Vir- GGGGATCCCTGAAGGAC), and the identity of the viroid confirmed by sequencing of the amplified fragment. The complete genome sequence obtained (GenBank Accession No. EF051631) shows 94 to 96% identity with other TASVd sequences in the databases, the highest homology being with the original Ivory Coast isolate (96%, 11 mutations, and 4 indels for the 362-nt genome). These results provide new information on the diversity of TASVd and of its detrimental potential for tomato crops and represent, to our knowledge, the first report of the presence of TASVd in Sénégal. References: (1) Y. Antignus et al. Phytoparasitica 30:502, 2002. (2) C. R. Walter. Acad. Sci. 292:537, 1981. (3) J. Th. J. Verhoeven et al. Plant Disease 90:528, 2006.
First Report of the Presence of Plum pox virus Rec Strain in Turkey
Authors: Candresse T. , Svanella-Dumas L. , Gentit P. , Caglayan K. , Çevik B. 
Published: May 2007

Plum pox virus (PPV) is a detrimental virus in stone fruit crops. Six strains of PPV are recognized, one of which, PPV-Rec, represents a group of isolates sharing a unique founding recombination event (2). This strain has been reported only from central and south-central Europe. Its distribution is of interest because PPV-Rec is reported to induce only weak and transient symptoms in GF305 peach seedlings, which may complicate its detection using this widely used indicator (2). During a field trip in May 2006, a Japanese plum (Prunus salicina) tree showing leaf symptoms reminiscent of PPV infection was identified in Isparta, Turkey. A leaf sample tested by a serological lateral flow PPV Pocket Diagnostic (Central Science Laboratory, Sand Hutton, UK) gave a weak positive reaction. The presence of PPV was confirmed by grafting onto GF305 peach and by PCR amplification and sequencing of a short P3M-P4b PCR product (1; positions 8446 to 8912 on PPV-BOR3; GenBank Accession No. AY028309) spanning the end of the NIb gene and the N-terminal hypervariable end of the coat protein gene. Comparison of the sequence obtained (GenBank Accession No. EF051630) with databases unambiguously identified the isolate as belonging to the Rec strain because it contained all the PPV-Rec specific mutations in the amplified region. In keeping with this identification, the symptoms observed in GF305 were very weak, consisting only of slight vein clearing on a few leaves. This is, to our knowledge, the first report of the presence of PPV-Rec in Turkey. References: (1) T. Candresse et al. Phytopathology 88:198, 1998. (2) M. Glasa et al. J. Gen. Virol. 85:2671, 2004.
First Report of Onion yellow dwarf virus, Leek yellow stripe virus, and Garlic common latent virus in Garlic in Oregon
Authors: Gieck S. L. , Pappu H. R. , Hamm P. B. , David N. L. 
Published: May 2007

A general mosaic and yellowing of leaves of three cultivars of garlic (Allium sativum L., Late, Early, and Germinador) were observed in two seed-production fields in Morrow County, OR in June 2005. Approximately 50% of plants within the 50-ha fields were symptomatic. With recent findings of Onion yellow dwarf virus (OYDV), Leek yellow stripe virus (LYSV), and Garlic common latent virus (GCLV) in Washington (2), 45 composite samples of 10 leaves each from symptomatic (mosaic and yellowing) and nonsymptomatic plants were analyzed with a GCLV-specific antiserum (Agdia Inc., Elkhart, IN). All samples of ‘Germinador’ were infected regardless of symptoms, whereas 6.7% of all ‘Late’ and ‘Early’ samples were positive. GCLV infection was verified by reverse transcription (RT)-PCR using primers specific to the coat protein gene of GCLV followed by cloning and sequencing of the cloned amplicon. To determine the presence of a potyvirus, all composite samples were also tested with a general potyvirus antiserum (Agdia) and all samples from symptomatic plants were found to be positive. Representative positive samples from each cultivar were then tested by RT-PCR using degenerate, potyvirus group specific primers (3), and an amplicon of the expected size was obtained. To confirm which potyvirus was present, amplicons were cloned and sequenced, and sequence comparisons indicated that the representative samples were infected with OYDV. All symptomatic samples from the three cultivars were positive for OYDV when tested by RT-PCR using primers specific to its coat protein gene (1). Additionally, 53.3 and 6.7% of ‘Early’ and ‘Late’ samples, respectively, were also positive when tested with LYSV-specific primers (4). LYSV infection was further verified through cloning and sequencing of the cloned amplicon. Because this garlic is grown for seed, studies are being initiated to determine if current season spread occurs and yields are reduced. To our knowledge, this is the first report of OYDV, LYSV, and GCLV in garlic in Oregon. References: (1) P. Lunello et al. J. Virol. Methods 118:15, 2004. (2) H. R. Pappu et al. Plant Dis. 89:205, 2005. (3) S. S. Pappu et al. J. Virol. Methods 41:9, 1993. (4) T. Tsuneyoshi et al. Phytopathology. 86:253, 1996.
First Report of White Mold Caused by Sclerotinia sclerotiorum on Iberis sempervirens in Italy
Authors: Garibaldi A. , Minuto A. , Gullino M. L. 
Published: May 2007

Iberis sempervirens (candytuft) is an ornamental plant that thrives in cool conditions, and its growth as a potted plant has been increasing in Liguria (northern Italy). In the spring of 2004, extensive chlorosis was observed on 10-month-old potted plants of I. sempervirens grown in a plastichouse on a commercial farm near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem and foliar necrosis progressed, infected plants wilted and died. Wilt occurred within a few days on young plants, characterized by the presence of soft, watery tissues, particularly on affected leaves. Symptomatic plants were found on many farms, with an average disease incidence of 5 to 10%. Necrotic tissues became covered with a whitish mycelium that produced dark sclerotia. The diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 1.4 to 3.2 × 2.1 to 4.1 mm (average 2.1 to 2.7 mm). Sclerotia produced on PDA measured 1.2 to 4.2 × 1.4 to 6.1 mm (average 2.5 to 3.1 mm). Pathogenicity of three isolates obtained from infected plants and used in a mixture was confirmed by inoculating 10 single-potted 120-day-old plants grown in 18-cm diameter pots maintained outside under shade. Inoculum that consisted of 1 cm2 of mycelium excised from a 10-day-old PDA culture plate of each isolate was placed on the soil surface around the base of each plant. Ten noninoculated plants served as control. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 8 and 17°C (average 12.5°C) and watered as needed. All inoculated plants developed symptoms of leaf yellowing within 18 days, soon followed by the appearance of white mycelium and sclerotia, and then eventual wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. S. sclerotiorum has been previously reported only on I. umbellata (2). To our knowledge, this is the first report of white mold on I. sempervirens in Italy as well as worldwide. The economic importance of this disease can be considered low at the moment in the case of field-grown plants. References: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift 75, 1949. (2) J. M. Waterston. Report of the Plant Pathologist, 1946. Dep. Agric. Bermuda, 1947.
First Report of Yucca Phyllody Associated with 16SrI-A Phytoplasmas in Texas
Authors: Lee I.-M. , Bottner K. D. , Black M. C. 
Published: May 2007

Buckley's yucca (Yucca constricta Buckl.) is a native flowering perennial plant widely distributed in Texas and northeast Mexico. It is also grown as an ornamental plant in its native range as well as in other dry regions in the United States and Mexico. In 2006, during an extended drought, Buckley's yucca plants sporadically exhibited phyllody and abnormal bud proliferation on the inflorescence in Uvalde County in southwestern Texas. Symptoms resembled those caused by phytoplasmal infection. Samples from four symptomatic and two asymptomatic yucca plants were collected. Total nucleic acid was extracted from abnormal bud tissue. To assess the etiological aspect of the disease nested PCR using phytoplasma specific primer pair P1/16S-SR or P1/P7 followed by R16F2n/R16R2n was employed for the detection of putative phytoplasmas (2). An amplicon of approximately 1.2 kb was amplified from all four symptomatic yucca plants but not from asymptomatic plants. Restriction fragment length polymorphism (RFLP) patterns of 16S rDNA digested singly with AluI, KpnI, HpaII, MseI, HhaI, and RsaI endonucleases indicated that affected yucca plants were infected by a phytoplasma belonging to aster yellows group 16SrI (‘Candidatus Phytoplasma asteris’), subgroup 16SrI-A (1). Nucleotide sequence analysis of cloned 16S rDNA (GenBank Accession No. EF190067) confirmed the results on the basis of RFLP analyses. Yucca phyllody has not been reported elsewhere. This disease appears to be newly emerging in Texas with only a few affected plants. To our knowledge, this is the first report of 16SrI-A phytoplasma infecting a Yucca sp. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) I.-M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004.
First Report of Gummy Stem Blight Caused by Didymella bryoniae on Grafted Watermelon in Tunisia
Authors: Boughalleb N. , El Mahjoub M. , Abad-Campos P. , Pérez-Sierra A. , García-Jiménez J. , Armengol J. 
Published: May 2007

During the summer of 2006, severe losses were observed in grafted watermelons in the Testour Region in northern Tunisia. Disease symptoms included stem cankers and necrosis and rot of the grafting area that extended a few centimeters along watermelon vines with the production of a brown gummy exudation. Lesions were not observed on leaves or nongrafted plants. Affected plants wilted and eventually died. The presence of small pseudothecia as black specks was observed embedded in the cankers. Isolations from the stems and crown of symptomatic plants onto potato dextrose agar (PDA) supplemented with 0.5 mg/ml of streptomycin sulfate consistently yielded cultures of a fungal agent. These isolates were transferred to PDA and V8 juice agar and incubated at 23°C for 1 month with a 12-h photoperiod. On PDA, they produced numerous pycnidia with hyaline, cylindrical, one-septate conidia, with mean dimensions of 6.7 × 2.5 μm. On V8 juice agar, they produced sparse ostiolate pseudothecia with bitunicate asci and hyaline, oval, one-septate ascospores, with mean dimensions of 13.7 × 5.1 μm. On the basis of these characters, the isolates were identified as Didymella bryoniae (anamorph Phoma cucurbitacearum) (1,2). To further confirm this identification, the complete internal transcribed spacer regions 1 and 2, including the 5.8S ribosomal DNA, of isolates Di-3 and Di-4 were sequenced (GenBank Accession Nos. EF107641 and EF 107642). These sequences were identical to sequences in GenBank from isolates of D. bryoniae (Accession Nos. AF297228 and AF495850). Pathogenicity tests were conducted on watermelon seedlings cv. Giza and Cucurbita hybrid rootstock seedlings cv. Strong Toza using two isolates, Di-3 and Di-4. Seedlings were inoculated at the two- to three-leaf stage. A 5-mm diameter agar disc, cut from the margin of an 8-day-old culture growing on PDA, was inserted in a basal stem wound made with a sterile scalpel at 2 cm above ground level and sealed with Parafilm. Controls were inoculated with sterile PDA discs. There were 10 replicates for each isolate and host with an equal number of uninoculated plants. Seedlings were maintained in a greenhouse at 23 to 25°C. Within 10 to 15 days after inoculation, symptoms developed as water-soaked lesions followed by necrosis and finally wilting. The fungus was reisolated from the stems of all inoculated plants, completing Koch's postulates. To our knowledge, this is the first report of D. bryoniae in Tunisia. References: (1) A. P. Keinath et al. Phytopathology 85:364, 1995. (2) E. Punithalingam and P. Holliday. No. 332 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.
First Report of Chrysanthemum stem necrosis virus on Chrysanthemums in Japan
Authors: Matsuura S. , Kubota K. , Okuda M. 
Published: May 2007

The chrysanthemum (Dendranthema grandiflorum), whose planted area comprises more than 6,000 ha in Japan, is one of the most important ornamental cut flower crops. In August 2006, necrotic streaks on stems, chlorotic and necrotic spots and rings on leaves, and leaf distortions were observed on chrysanthemum cvs. Jimba and Seinotama, with a disease incidence of more than 70% (approximately 30,000 plants), which represents approximately 1,000 m2 of greenhouses of one grower in Hiroshima Prefecture, western Japan. Symptoms were similar to those caused by Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae). Frankliniella occidentalis was the major thrips species observed on symptomatic plants, followed by F. intonsa. Tospovirus-like spherical particles that were 80 to 100 nm in diameter were found in the infected leaves. After mechanical inoculation, a single lesion isolate reproduced the original symptoms observed in nature on healthy chrysanthemum plants (cv. Jimba). As determined by mechanical inoculation, host range and symptomatology of the isolate were similar to those described previously for Chrysanthemum stem necrosis virus (CSNV), including necrotic spots on Petunia hybrida (1). The isolate caused stunting, severe necrotic lesions on stems, necrotic spots, rings, and vein necrosis on systemically infected leaves of Lycopersicon esculentum (cv. House-momotaro). This virus reacted strongly with CSNV antiserum (DSMZ, Braunschweig, Germany) by indirect dot immuno-binding assay, and cross-reacted weakly with a monoclonal antibody to N protein of TSWV (3) using double-antibody sandwich-ELISA. Reverse transcription (RT)-PCR was conducted to verify virus infection. No amplification was observed from extracts of symptomatic plants (n = 10) by multiplex RT-PCR using TSWV and Impatiens necrotic spot virus specific primer sets (4), indicating that the diseased chrysanthemums were not doubly infected with these viruses. However, a DNA fragment of approximately 450 bp was amplified in samples by RT-PCR using tospovirus universal primers, BR60/65 (2). The nucleotide sequence of the amplified fragment had 98.1% identity with the corresponding region of the CSNV nucleocapsid protein gene (GenBank Accession No. AF067068). The above results indicate that the virus associated with a stem necrosis disease of chrysanthemums in Hiroshima is an isolate of CSNV. To our knowledge, this is the first report of CSNV in Japan. References: (1) I. C. Bezerra et al. Phytopathology 89:823, 1999. (2) M. Eiras et al. Fitopatol. Bras. 26:170, 2001. (3) S. Tsuda et al. Ann. Phytopathol. Soc. Jpn. 60:216, 1994. (4) H. Uga and S. Tsuda. Phytopathology 95:166, 2005.
First Report of Arceuthobium aureum subsp. aureum in Mexico
Authors: Mathiasen R. , Howell B. , Garnett G. 
Published: May 2007

The golden dwarf mistletoe (Arceuthobium aureum Hawksw. & Wiens subsp. aureum, Viscaceae) parasitizes several pines (Pinus spp., Pinaceae) in central Guatemala (1). In September 2006, we observed golden dwarf mistletoe parasitizing Pinus maximinoi H.E. Moore in southern Chiapas, Mexico; 1 km west of El Rosario along Mexico Route 211 (15°19′23″N, 92°17′45″W, elevation 1,720m). Golden dwarf mistletoe can be distinguished from the closely related Peterson's dwarf mistletoe (A. aureum Hawksw. & Wiens subsp. petersonii Hawksw. & Wiens) by its smaller shoots, occurrence below 2,200 m in elevation, and flowering period (1). The shoots of the dwarf mistletoe at the El Rosario location were less than 20 cm high and male plants were not flowering. Male plants of Peterson's dwarf mistletoe observed at the type locality and other locations in Chiapas during September were in full flower. Although only 29 trees were infected at this location, infection was severe on 11 trees, but no mortality associated with dwarf mistletoe infection was observed. Mistletoe infection did not induce the formation of witches'-brooms near El Rosario, but infection by golden dwarf mistletoe on P. maximinoi does induce witches'-brooms on older trees in Guatemala (2). The golden dwarf mistletoe population near El Rosario is approximately 150 km west of the nearest known population of this species in Guatemala (1). To our knowledge, this is the first report of golden dwarf mistletoe in Mexico. Specimens of golden dwarf mistletoe from Chiapas, Mexico were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff (Accession No. 83122). References: (1) F. Hawksworth and D. Wiens. Dwarf Mistletoes: Biology, Systematics, and Pathology. USDA For. Serv. Agric. Handb. 709, 1996. 2) R. Mathiasen et al. Madrono 23:122, 2004.