First Report of Phaeomoniella chlamydospora on Vitis vinifera and French American Hybrids in Chile

Phaeomoniella chlamydospora (W. Gams, Crous. M.J. Wingfield & L. Mugnai) Crous & Gams (= Phaeoacremonium chlamydosporum) was isolated during the growing seasons of 2003-2004 from roots, trunks, and cordons of grapevines, including cvs. Cabernet Sauvignon, Merlot, Pinot noir, Thompson seedless, Ruby seedless and root stock 3309C, and Kober 5BB, from 10 locations in V, VI, VII, and metropolitan regions of Chile. P. chlamydospora was isolated from 82% of samples from vines 2 to 18 years old that showed decline symptoms in the field. Isolates were identified on the basis of a previous description (1) and internal transcribed spacer (ITS1-5.8S-ITS2) rDNA sequences identical to those of P. chlamydospora isolated from Vitis vinifera (culture CBS 22995, GenBank Accession No. AF 197973). P. chlamydospora is established as a member of the petri and esca disease complex and as a pathogen of grapevines (2,3). Pathogenicity tests were completed by injecting into the pith of 50 single-node, rooted cuttings of Pinot noir and 3309C, approximately 20 μl of a 106 conidia per ml suspension, obtained from four isolates from Chile and one from California. Ten control cuttings of Pinot noir and 3309C were injected with an equal volume of sterile distilled water. Twenty-four weeks after inoculations, all P. chlamydospora-inoculated cuttings exhibited dark streaking of the vascular tissue extending 40 to 45 mm from the point of inoculation. The vascular streaking observed in inoculated plants was identical to symptoms observed in declining vines in the vineyard. No symptoms were observed in the controls. P. chlamydospora was isolated from the region of vascular streaking in 85% of inoculated cuttings. P. chlamydospora was not isolated from the water-treated controls. The reisolated P. chlamydospora was verified with means of morphological characters and polymerase chain reaction amplification with the species-specific primers (3). P. chlamydospora is widespread and readily isolated from declining grapevines in Chile and other grape growing regions of the world. To our knowledge, this is the first report of P. chlamydospora from the cultivars cited above in Chile. References: (1) M. Groenewald et al. Mycol. Res. 105:651, 2001. (2) L. sparapano et al. Phytopathol. Mediterr. (Suppl.)40:376, 2001. (3) S. Tegli et al. Phytopathol. Mediterr. 39:134, 2000.

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First Report of Phaeomoniella chlamydospora on Vitis vinifera, Vitis labrusca, and French American Hybrids in Pennsylvania and New York

Plant Disease ◽

10.1094/pdis.2003.87.6.750b ◽

2003 ◽

Vol 87 (6) ◽

pp. 750-750

Author(s):

E. L. Stewart ◽

N. G. Wenner ◽

B. E. Hed

Keyword(s):

New York ◽

Vitis Vinifera ◽

Lake Erie ◽

Vascular Tissue ◽

Single Node ◽

First Report ◽

Phaeomoniella Chlamydospora ◽

Growing Seasons ◽

Rdna Sequences ◽

Root Stock

Phaeomoniella chlamydospora (W. Gams, Crous, M.J. Wingfield. & L. Mugnai) Crous & Gams (= Phaeoacremonium chlamydosporum) was isolated during the growing seasons of 2001 and 2002 from roots, trunks, and cordons of grapevines including cultivars Concord, Niagara, Steuben, Catawba, Dutchess, DeChaunac, Vidal, Seyval, Chambourcin, Chardonnay, Riesling, Sangiovese, Dolcetto, Baco Noir, Merlot, Villard, Pinot Gris, GR7, and 3309C root stock representing 18 locations in Eastern, Central, and Lake Erie regions of Pennsylvania as well as the Lake Erie and Finger Lakes regions of New York. P. chlamydospora was isolated from 89% of samples from vines 3 to 45 years old showing decline symptoms in the field. Isolates were identified based on a previous description (1) and by internal transcribed spacer (ITS1-5.8S-ITS2) rDNA sequences identical to those of P. chlamydospora isolated from Vitis vinifera from Italy (ex-type culture CBS229.95, GenBank Accession No. AF197973). P. chlamydospora is firmly established as a member of the petri and esca disease complex and as a pathogen of grapevines (2,3). To test pathogenicity of our isolates, approximately 30 μl of a 106 conidia/ml suspension, obtained from six isolates, was injected into the pith of 60 single-node, dormant, unrooted cuttings of ‘3309C’ and ‘Concord’. Ten control cuttings of ‘Concord’ and ‘3309C’ were injected with an equal volume of sterile distilled water. From 24 to 32 weeks after inoculations, all P. chlamydospora-inoculated cuttings exhibited dark streaking of the vascular tissue extending 45 to 50 mm from the point of inoculation. The vascular streaking observed in inoculated plants was identical to symptoms observed in declining vines in the vineyard. Vascular streaking was absent in the controls. P. chlamydospora was isolated as a monoculture from regions of vascular streaking in 89% of inoculated cuttings. P. chlamydospora was not isolated from the water-treated controls. P. chlamydospora is widespread and readily isolated from declining grapevines in Pennsylvania, New York, and other national and international grape growing regions. To our knowledge, this is the first report of P. chlamydospora from the cultivars cited above in Pennsylvania and New York. References: (1) M. Groenewald et al. Mycol. Res. 105:651, 2001. (2) Phytopathol. Mediterr. 39(1), 2000. (3) Phytopathol. Mediterr. 40, Supplement 2001.

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Black Dead Arm and Basal Canker of Vitis vinifera cv. Red Globe Caused by Botryosphaeria obtusa in Chile

Plant Disease ◽

10.1094/pdis.2004.88.11.1286a ◽

2004 ◽

Vol 88 (11) ◽

pp. 1286-1286 ◽

Cited By ~ 39

Author(s):

J. Auger ◽

M. Esterio ◽

G. Ricke ◽

I. Pérez

Keyword(s):

Vitis Vinifera ◽

Ground Level ◽

Severe Form ◽

Single Node ◽

Pathology Laboratory ◽

Metropolitan Regions ◽

Rdna Sequences ◽

Botryosphaeria Obtusa ◽

The University ◽

Black Dead Arm

Several years ago, Vitis vinifera cv. Red Globe vines (over 6 years old), started to show disease symptoms approximately 10 weeks after bud break. Symptoms first appeared on the leaves at the base of the shoots and then spread to other leaves, continuing to appear throughout the growing season. Two forms of the disease (severe and mild) were observed, each case leading to premature leaf fall. The severe form was characterized by dieback of one or more shoots accompanied by leaf drop and shriveling and drying of fruit clusters. The mild form was characterized by wine-red spots on the leaf margins or the leaf blade, which coalesced to form large zones of necrosis between the veins and the margins of the leaf. Fruit clusters may wither. If the bark is scraped off, a brown streak, 1 to 2 cm wide, was often seen in the wood. The streaking began at the base of the affected shoot and extended upward to the ground level, eventually resulting in a basal canker. Botryosphaeria obtusa (Schwein.) Shoemaker (anamorph = Sphaeropsis malorum Berk.) was isolated from 86% of samples from vines that were 6 to 10 years old from 12 locations in IV, V, VI, and metropolitan regions of Chile. Isolations were made from brownstreaked wood. Isolates were identified on the basis of a previous description (1,2) and internal transcribed spacer (ITSI-5.8S-ITS2) rDNA sequences identical to those of B. obtusa (culture KJ9356, GenBank Accession No. AF027759). B. obtusa is established as one of the main fungi associated with black dead arm of grapevine (2,3). Pathogenicity tests were completed by inoculating approximately 20 μl of mycelial suspension via injection into the pith of 16 single-node, rooted cuttings of V. vinifera cv. Red Globe. Sixteen control cuttings were injected with an equal volume of sterile distilled water. Twenty weeks after inoculation, all B. obtusa-inoculated cuttings exhibited brown streaks in the wood extending 50 to 60 mm from the point of inoculation. The wood streaking observed in inoculated plants was identical to symptoms observed in naturally infected black dead arm vines in the vineyard. No symptoms were observed in the controls. B.obtusa was reisolated from the region of brown streaking in all the inoculated cuttings. B. obtusa was not isolated from the water-treated controls. To our knowledge, this is the first report of B. obtusa causing black dead arm and basal canker on Red Globe grapevine in Chile. The fungal isolates have been deposited in the plant pathology laboratory of the Sanidad Vegetal Department of Agronomy Faculty of the University of Chile under the name V. vinifera/B. obtusa from N 1 to 16. References: (1) G. Cristinzio. Inf. Fitopatol. 28:21, 1978. (2) P. Larignon and B. Dubos. Phytoma 538:26, 2001. (3) A. J. L. Phillips. J. Phytopathol. 146:327, 1998.

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First Report of Perithecia of Phaeoacremonium viticola on Grapevine (Vitis vinifera) and Ash Tree (Fraxinus latifolia) in California

Plant Disease ◽

10.1094/pd-89-0686b ◽

2005 ◽

Vol 89 (6) ◽

pp. 686-686 ◽

Cited By ~ 4

Author(s):

A. Eskalen ◽

S. Rooney-Latham ◽

W. D. Gubler

Keyword(s):

Vitis Vinifera ◽

Room Temperature ◽

Vascular Tissue ◽

Molecular Data ◽

Thompson Seedless ◽

Phaeomoniella Chlamydospora ◽

Esca Disease ◽

Ash Trees ◽

Sexual State ◽

First Time

Esca and Petri diseases on grapevine are caused by Phaeomoniella chlamydospora and species of Phaeoacremonium including P. aleophilum, P. viticola, P. angustius, P. parasiticum, P. inflatipes, P. rubrigenum, and P. mortoniae. The teleomorphs of P. aleophilum and P. mortoniae have been recently confirmed as Togninia minima(Tul. & C. Tul.) Berl. (2,3), and T. fraxinopennsylvanica (Hinds) Hausner, Eyjólfsdóttir & J. Reid, respectively (1,2,3). Teleomorphs of other Phaeoacremonium spp. have not been identified, although molecular data suggests that Phaeaoacremonium spp. are linked to the genus Togninia. Naturally infected vineyards with symptoms of esca disease were surveyed during the summer and fall of 2004. Samples were collected from declining ash trees surrounding the vineyards, as well as from symptomatic grapevine trunks, cordons, and spurs. Samples were processed as previously described (1). Sterile isolations were also made from symptomatic vascular tissue of the samples and cultured on potato dextrose agar (PDA)-tet medium. Perithecia were found on the surfaces of old pruning wounds and in the cracks of cordons and trunks on Vitis vinifera cvs. Thompson Seedless, Riesling, and Cabernet Sauvignon. Perithecia were observed on grapevines in vineyards in six of nine counties, viz. Yolo, Mendocino, El Dorado, Tulare, Madera, and Sonoma. Perithecia were also observed in dead vascular tissue of declining ash tree branches (Fraxinus latifolia) located in the vicinity of vineyards in Sonoma and Yolo counties. Perithecia were black, globose to subglobose, ranging from 160 to 215 μm in diameter, and were both embedded in and superficial on the wood tissue. Neck lengths ranged from 55 to 340 μm. The asci were hyaline, clavate, and ranged in size from 12.5 to 19.5 × 3.2 to 4.5 μm. Ascospores were hyaline, ellipsoid to allantoid, and ranged in size from 3.1 to 4.1 × 1.8 to 2.1 μm. Morphologically these perithecia resemble those of Togninia spp. When plated onto PDA-tet medium, ascospores formed colonies of P. viticola after 10 days of incubation at room temperature. Additionally, P. viticola was isolated from vascular tissue of the collected plant specimens. To our knowledge, this is the first time that P. viticola has been linked to a sexual state. References: (1) A. Eskalen et al. Plant Dis. 89:528, 2005. (2) L. Mostert et al. Mycologia 95:646, 2003. (3) S. Rooney-Latham. Plant Dis. 89:177, 2005.

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First Report of Diaporthe australafricana Associated with Stem Canker on Blueberry in Chile

Plant Disease ◽

10.1094/pdis-12-11-1025-pdn ◽

2012 ◽

Vol 96 (5) ◽

pp. 768-768 ◽

Cited By ~ 3

Author(s):

B. A. Latorre ◽

K. Elfar ◽

J. G. Espinoza ◽

R. Torres ◽

G. A. Díaz

Keyword(s):

Vitis Vinifera ◽

Vascular Tissue ◽

Its Region ◽

Pathogenic Fungi ◽

Stem Canker ◽

Vaccinium Corymbosum ◽

Academic Press ◽

First Report ◽

Potted Plants ◽

Blastn Analysis

Stem cankers of blueberry (Vaccinium corymbosum L.) have been observed on as much as 15% of the plants in plantations in central and southern Chile since 2006. Symptoms consisted of apical necrosis of the shoots and brown-to-reddish necrotic lesions on the stems. Internally, a brown-to-reddish discoloration of the vascular tissue can be observed. Twenty, single-plant samples were collected in 12 blueberry plantings (approximately 33°27′ to 40°53′S). Isolations from the margins of the necrotic lesions on the stems were made by plating small pieces (5 mm) on potato dextrose agar acidified with 0.5 μl/ml of 92% lactic acid (APDA). The plates were incubated at 20°C for 5 to 7 days, and hyphal tips of white colonies with septate and hyaline mycelium were transferred to APDA. Colonies were then transferred to autoclaved Pinus radiata needles on 2% water agar and incubated for 20 days at 20°C. Twelve isolates producing black pycnidia and alpha conidia were tentatively identified as a Phomopsis sp. (teleomoph Diaporthe Nitschke). Other fungi, including Botryosphaeriaceae spp. and Pestalotiopsis spp., were also isolated. Alpha conidia were smooth, unicellular, hyaline, fusoid, biguttulate, and 6.4 to 7.9 × 2.3 to 3.3 μm (n = 20). Beta conidia were not observed. The internal transcribed spacer (ITS) region of the rDNA was amplified using primers ITS1 and ITS2 (4) and sequenced. BLASTn analysis of the 473-bp fragment (GenBank Accession No. JQ045712) showed 100% identity to Diaporthe australafricana Crous & J.M. van Niekerk from Vitis vinifera (3). The pathogenicity of D. australafricana was studied on blueberry cv. O'Neal using detached stems (n = 4) in the laboratory, on 2-year-old potted plants (n = 4) in a greenhouse, and on attached stems of mature plants (n = 4) established in the ground. Inoculations were done by placing mycelial plugs taken from 7-day-old APDA cultures in a 7-mm long incision made on the stems. Inoculations with sterile mycelium plugs served as negative controls. Inoculation sites were wrapped with Parafilm to avoid rapid dehydration. Dark brown, necrotic lesions on the internal tissues were obtained on all inoculated stems 15 days after inoculation. Mean lesion lengths were 18.0 ± 7.4 mm on detached stems, 7.8 ± 6.9 mm on stems of 2-year-old plants, and 7.3 ± 2.5 mm on mature plants in the field. No symptoms developed on control stems. Reisolations were successful in 100% of the inoculated stems and D. australafricana was confirmed by the presence of pycnidia and alpha conidia. To our knowledge, this is the first report of D. australafricana causing stem canker in V. corymbosum. Previously, this pathogen has been reported to be affecting Vitis vinifera in Australia and South Africa (3). These results do not exclude that other plant-pathogenic fungi may be involved in this syndrome (1,2). References: (1) J. G. Espinoza et al. Plant Dis 92:1407, 2008. (2) J. G. Espinoza et al. Plant Dis. 93:1187, 2009. (3) J. M. van Niekerk et al. Australas. Plant Pathol. 34:27, 2005. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, NY, 1990.

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First Report of Wilt on Alfalfa in China Caused by Verticillium nigrescens

Plant Disease ◽

10.1094/pdis-07-11-0580 ◽

2011 ◽

Vol 95 (12) ◽

pp. 1591-1591 ◽

Cited By ~ 3

Author(s):

X. P. Hu ◽

M. X. Wang ◽

D. F. Hu ◽

J. R. Yang

Keyword(s):

Vascular Tissue ◽

Its Region ◽

Morphological Characters ◽

Deionized Water ◽

Nuclear Ribosomal Dna ◽

Cow Dung ◽

Its Sequence ◽

Its Sequencing ◽

First Report

Alfalfa (Medicago sativa Linn.), widely grown throughout the world, is an important perennial forage crop. It is high in protein and digestible fiber and is an excellent source of several vitamins (A, D, E, and K) and minerals for beef cattle, horses, sheep, goats, and even humans (2). Wilt symptoms on alfalfa were observed during a disease survey in Yangling, Shaanxi, China in 2009. Symptoms included discoloration, shortened internode, and plant death. However, the vascular tissue of diseased alfalfa plants did not exhibit discoloration and typical “V” symptoms of Verticillium albo-atrum infection. Eleven fungal isolates were obtained from diseased alfalfa plants in Yangling by a tissue isolation method (1). Isolates were cultured on Czapek Dox Agar (CDA; pH 7.2) slants at 22 ± 1°C in darkness. Colonies on CDA plates were whitish and cream-white when viewed from the underside, later becoming dark gray due to the formation of gray or dark brown chlamydospores in single or in short chains. DNA was extracted from each isolate and the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA (rDNA) was amplified and sequenced using primers ITS-1F and ITS4. The 11 isolates were divided into five groups based on their in vitro morphological characters. A single isolate from each of the five groups was chosen for ITS sequencing. All five isolates had the same ITS sequence (GenBank Accession No. AB551216). On the basis of the ITS sequence and morphology (4), these isolates were identified as V. nigrescens Pethyhr. (recently renamed as Gibellulopsis nigrescens). Five representative isolates were used to fulfill Koch's postulates. Alfalfa seeds (cv. Cossack) were surface sterilized with 75% ethanol for 5 min, allowed to dry, and planted into cow dung compost that had been autoclaved at 160°C for 2 h. Plants were cultivated under controlled greenhouse conditions at 23 to 25°C with a photoperiod of 14 h. Inoculum was prepared by comminuting 15-day-old cultures and sterile deionized water into a suspension of mycelial fragments and conidia (105 to 106 CFU/ml) in a blender. Seedlings (four-leaf stage) were inoculated by immersing roots in the inoculum suspension for 60 min (3). Each isolate was inoculated onto 30 seedlings, six in each pot; another 30 seedlings were soaked with sterile deionized water for 60 min as a control. After 20 days in the greenhouse, all inoculated plants exhibited wilt symptoms similar to the original wilt symptoms observed on diseased alfalfa plants. In contrast, none of the control plants showed wilt symptoms. The pathogen was reisolated from all diseased plants and confirmed to the original ones. To our knowledge, this is the first report of V. nigrescens infecting M. sativa in China, indicating V. nigrescens as one possible important pathogen of alfalfa. References: (1) O. D. Dhingra and J. B. Sinclair. Basic Plant Pathology Methods. CRC Press, Boca Raton, FL, 1995. (2) D. Jasjeet et al. J. Adv. Sci. Res. 2:50, 2011. (3) H. A. Melouk and C. E. Horner. Phytopathology 64:1267, 1974. (4) R. Zare et al. Nova Hedwigia 85:463, 2007.

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First Report of Brown Rot in Wine Grapes Caused by Monilinia fructicola in Canada

Plant Disease ◽

10.1094/pdis.2003.87.10.1268b ◽

2003 ◽

Vol 87 (10) ◽

pp. 1268-1268 ◽

Cited By ~ 4

Author(s):

P. L. Sholberg ◽

P. D. Haag ◽

S. Hambleton ◽

H. Boulay

Keyword(s):

Vitis Vinifera ◽

Sequence Data ◽

Brown Rot ◽

Plant Diseases ◽

Pinot Noir ◽

Rrna Genes ◽

Monilinia Fructicola ◽

Its Sequence ◽

Wine Grapes ◽

First Report

A survey was conducted in 2001 and 2002 to determine incidence of fruit pathogens in wine grapes (Vitis vinifera), an important crop in the southern interior of British Columbia (BC), Canada. Grape clusters were sampled every 2 weeks from June to October at eight vineyard sites located from Osoyoos in the south to Kelowna, approximately 100 km to the north. In the laboratory, the berry clusters were surface disinfested for 0.5 min in 70% ethanol, followed by 1 min in 0.5% sodium hypochlorite, and rinsed twice in sterile distilled water. The berries were placed on potato dextrose agar (PDA) amended with 15 ml/liter of 85% lactic acid and incubated at 20°C for 1 week. During the 2002 survey, a fungus resembling Monilinia fructicola (G. Wint.) Honey was observed sporulating on immature ‘Pinot noir’ grapes from Kelowna that were sampled on 14 August. Later in the growing season, a similar fungus was detected on ‘Riesling’ grapes from Summerland sampled on 11 September. There was no evidence of brown rot near the vineyard in Kelowna, but diseased stonefruit were present near the vineyard in Summerland. Subsequent identification of the fungus from ‘Riesling’ as M. fructicola was based on morphological characters and DNA sequence data for the internal transcribed spacer (ITS) regions of the nuclear ribosomal rRNA genes. The sequenced isolate was deposited in the Canadian Collection of Fungus Cultures as DAOM 231119, and the ITS sequence was accessioned in GenBank as AY289185. Colony growth on PDA was rapid and in concentric rings with the colony margin complete, microconidia abundant, and macroconidia 12 to 13 μm long. Macroconidia germinated with a long germ tube before branching. These characteristics distinguished this fungus from M. laxa, a closely related species that is slow growing with lobed colony margins, produces few microconidia, and germ tubes that branch close to the conidium (1). The complete ITS sequence for DAOM 231119 was a 100% match to other sequences deposited for M. fructicola (Z73777, AF010500, and U21815). On the basis of comparisons of available data, ITS sequences for M. fructicola (three complete ITS, seven partial ITS) and M. laxa (8 complete ITS, 10 partial ITS) differed consistently at four nucleotide positions. The fungus identified as M. fructicola was tested for pathogenicity on mature surface-sterilized ‘Pinot noir’ and ‘Riesling’ grapes. Under humid conditions, buff-colored sporodochia bearing conidia developed over the surface of the infected berries. This indicates that M. fructicola can cause decay of wine grapes and could be confused with bunch rot caused by Botrytis cinerea. Previously, M. fructicola was reported on grapes in Oklahoma, but likely these grapes were not Vitis vinifera (2). To our knowledge, this is the first report of brown rot caused by M. fructicola on wine grapes in North America. References: (1) L. R. Batra. World Species of Monilinia (Fungi): Their Ecology, Biosystematics and Control. Mycologia Memoir No. 16. Gerbrüder Borntraeger, Berlin/Stuttgart, 1991. (2) D. A. Preston. Host Index of Oklahoma Plant Diseases, Tech. Bull. No. 21. Oklahoma Agricultural and Mechanical College, Agricultural Experiment Station, Stillwater, 1945.

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First Report of Verticillium Wilt of Grapevine (Vitis vinifera) Caused by Verticillium dahliae in China

Plant Disease ◽

10.1094/pdis-93-8-0841c ◽

2009 ◽

Vol 93 (8) ◽

pp. 841-841 ◽

Cited By ~ 4

Author(s):

L. Zhang ◽

G. L. Zhang ◽

X. Qian ◽

G. Y. Li

Keyword(s):

Vitis Vinifera ◽

Verticillium Wilt ◽

Verticillium Dahliae ◽

Sequential Analysis ◽

Vascular Tissue ◽

Tap Water ◽

The United States ◽

Conidial Suspension ◽

First Report ◽

5.8S Rdna

Verticillium dahliae Kleb. causes Verticillium wilt in large numbers of crops all over the world. Common symptoms caused by the pathogen include yellowing, wilting of leaves, and discoloration in vascular tissue of the stem. In June 2007, symptoms of Verticillium wilt were observed in a grapevine (Vitis vinifera) field in the Shihezi Region of Xinjiang. To isolate the pathogen, stem segments (0.5 cm long) were surface sterilized with 1% HgCl2 for 1 min and then dipped in 70% ethanol for 10 s. The sterilized tissues were rinsed with sterile water and incubated in the dark for 7 days at 25°C on potato dextrose agar (PDA) medium. The fungus growing from the diseased tissue showed dark colonies that produced verticillate conidiophores with two to three layers with colorless, ovoid, unicellular conidia and small, black microsclerotia, which are characteristics of V. dahliae (3). To confirm its identity, ribosomal DNA fragments (regions ITS1, 5.8S rDNA, and ITS4) were PCR amplified with primer pair ITS1/ITS4 (4) and sequenced (GenBank Accession No. FJ475122). Sequential analysis revealed that the rDNA region of the fungus isolated from grapevine was identical to that of a Greek strain of V. dahliae (GenBank Accession No. AF104926). Furthermore, the specific fragment (1,500 bp) of nondefoliating pathotype of V. dahliae (1) was PCR amplified from 24 grapevine isolates of V. dahliae collected in Xinjiang, indicating that the V. dahliae pathogen from Xinjiang is a nondefoliating pathotype. To verify the causal role of the isolated fungus, pathogenicity assays were conducted on 1-year-old seedlings of the Centennial seedless cultivar. Trimmed roots were submerged in a conidial suspension (1 × 106 conidia/ml) for 30 min and sterile tap water was used as a control. The seedlings were transplanted into a pot containing 2:1 sterile mixture of peat/perlite (vol/vol). Plants were grown in a greenhouse at 25°C. Six Verticillium isolates were found to cause the same symptoms as in fields 50 days after inoculation. V. dahliae was successfully reisolated from the stems of inoculated plants. Control seedlings inoculated in sterile tap water remained healthy. Because grapevine (Vitis vinifera) is an economically important crop for fruit and winemaking material in Xinjiang, Verticillium wilt poses a threat. The disease has been previously reported in the United States (2), but to our knowledge, this is the first report from China. References: (1) E. Pérez Artés et al. Eur. J. Plant Pathol. 106:507, 2000. (2) W. C. Schnathorst and A. C. Goheen. Plant Dis. Rep. 61:909, 1977. (3) H. C. Smith. N. Z. J. Agric. Res. 8:450, 1965. (4) T. J. White et al. PCR Protocols. Academic Press, San Diego, CA, 1990.

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First Report of Diplodia corticola Causing Grapevine (Vitis vinifera) Cankers and Trunk Cankers and Dieback of Canyon Live Oak (Quercus chrysolepis) in California

Plant Disease ◽

10.1094/pdis-94-6-0785a ◽

2010 ◽

Vol 94 (6) ◽

pp. 785-785 ◽

Cited By ~ 13

Author(s):

J. R. Úrbez-Torres ◽

F. Peduto ◽

S. Rooney-Latham ◽

W. D. Gubler

Keyword(s):

Vitis Vinifera ◽

Dna Sequences ◽

Vascular Tissue ◽

Aerial Mycelium ◽

Lesion Length ◽

First Report ◽

Live Oak ◽

General Decline ◽

Vascular Discoloration ◽

Oak Tree

The botryosphaeriaceous fungus Diplodia corticola A. J. L. Phillips, Alves & Luque was shown to be the most prevalent canker and dieback pathogen in cork oaks (Quercus suber L.) in the Iberian Peninsula causing a general decline of the trees as a consequence of canker formation in the trunks (1). In addition, D. corticola has been recently reported as a grapevine pathogen causing cankers in the vascular tissue of 1-year-old canes, spurs, and cordons in Texas (3). In 1998, Jacobs and Rehner reported one isolate of D. corticola from oak in California, but no information regarding the oak species from which the isolate was obtained and its virulence were available in the study (2). In 2009, D. corticola was isolated on potato dextrose agar (PDA) amended with 0.01% tetracycline hydrochloride from symptomatic grapevine cordons and on acidified PDA from the trunk of a canyon live oak tree from Sonoma and Plumas counties, respectively. Two grapevine isolates (UCD1260So and UCD1275So) and one oak isolate (CDFA519) were examined and morphologically compared with previously identified D. corticola isolates CBS678.88 and UCD2397TX from cork oak from Spain and grapevine in Texas, respectively. D. corticola colonies from California were characterized by moderately fast-growing, dark olivaceous, and dense aerial mycelium on PDA. Conidia were obtained from pycnidia formed on pine needles placed on 2% water agar. Conidia were hyaline, contents granular, aseptate, thick walled, ellipsoidal, sometimes becoming dark brown and septate with age. Nucleotide sequences of three genes (ITS1-5.8S-ITS2, a partial sequence of the beta-tubulin gene BT2, and part of the translation elongation factor EF1-α) from D. corticola isolates UCD1260So, UCD1275So, and CDFA519 from California were amplified. All DNA sequences from grapevine and oak tree isolates from California showed 99 to 100% homology with D. corticola isolates previously identified and deposited into GenBank. All DNA sequences obtained from Californian isolates were also deposited into GenBank. Pathogenicity tests were conducted by inoculating detached Vitis vinifera cv. Red Globe dormant canes and canyon live oak branches with agar plugs of isolates UCD1260So, UCD1275So, and CDFA519 (10 inoculations per isolate per host) as described by Úrbez-Torres et al. (3). The same number of grapevine canes and oak branches were inoculated with noncolonized agar plugs as controls. Six weeks after inoculation, the extent of vascular discoloration that developed from the point of inoculation was measured. D. corticola isolates UCD1260So, UCD1275So, and CDFA519 caused an average vascular lesion length of 30.4, 29.6, and 24 mm and 15, 13.2, and 8.6 mm in grapevine dormant canes and oak branches, respectively. Furthermore, D. corticola isolates from grapevine were pathogenic in oak branches and vice versa. Reisolation of D. corticola from discolored vascular tissue of inoculated material was 100%. The extent of vascular discoloration from inoculated grapevine canes and oak branches was significantly greater (P < 0.05) compared with the controls (1.8 and 2 mm, respectively). No fungi were reisolated from the slightly discolored tissue of the controls. To our knowledge, this is the first report of D. corticola causing grapevine cankers and oak trunk cankers in California. References: (1) A. Alves et al. Mycologia 96:598, 2004. (2) K. A. Jacobs and S. A. Rehner. Mycologia 90:601, 1998. (3) J. R. Úrbez-Torres et al. Am. J. Enol. Vitic. 60:497, 2009.

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First Report of Juneberry Rust Caused by Gymnosporangium nelsonii on Juneberry in Michigan

Plant Disease ◽

10.1094/pdis-12-10-0874 ◽

2011 ◽

Vol 95 (6) ◽

pp. 770-770

Author(s):

A. M. C. Schilder ◽

E. M. Lizotte ◽

H. Y. Yun ◽

L. J. Dixon ◽

L. A. Castlebury

Keyword(s):

New York ◽

Great Plains ◽

Signs And Symptoms ◽

Morphological Characters ◽

28S Rdna ◽

Northern Great Plains ◽

State University ◽

First Report ◽

Rdna Sequences ◽

Side Walls

Amelanchier alnifolia (Nutt.) Nutt. ex M. Roem., commonly known as juneberry or Saskatoon serviceberry, was historically a widely used prairie fruit that is native to the Northern Great Plains, southern Yukon and Northwest Territories (4). While juneberry is an important fruit crop in the prairie provinces of Canada, small commercial plantings also occur throughout the northern United States (2), including Michigan. On July 18, 2009, severe rust symptoms were observed on plants in a 2-year-old field of A. alnifolia ‘Northline’ in Northport, MI. The plants had been sourced as seedlings from a nursery in Alberta, Canada in 2007. Signs and symptoms were present on fruits and leaves on virtually all of the plants. Symptomatic fruit were still immature, and on average, more than 70% of the fruit surface was covered with tubular, whitish aecia with conspicuous orange aeciospores. Portions of twigs also showed fusiform swellings (1 to 3 cm long) covered with aecia. Aecia were hypophyllous, fructicolous and caulicolous, roestelioid, and 2 to 4 mm high. The peridium was cylindric and tapering toward the apex, dehiscent at the apex, retaining a tubular shape for a long time and at times becoming lacerated on the sides with age. Peridial cells were linear rhomboidal, 50 to 105 μm long, hyaline to brownish, outer walls smooth, inner walls with small papillae, and side walls delicately verrucose-rugose with elongate papillae having variable lengths. Aeciospores were globoid, 20 to 35 × 25 to 38 μm (average 30.7 × 32.5 μm), orange to cinnamon brown, and densely verrucose with walls 2.5 to 3.5 μm thick. On the basis of these morphological characters, the host, and comparison with a reference specimen (BPI 122010), the pathogen was identified as Gymnosporangium nelsonii Arthur (1,3). The 5′ region of the 28S rDNA was sequenced (GenBank Accession No. HM591299.1), confirming the identification as a species of Gymnosporangium, one distinct from previously sequenced specimens available in GenBank. The specimen has been deposited at the U.S. National Fungus Collections (BPI 880671 and 880709). Four other species found previously on Amelanchier spp. in the Midwest differ as follows: G. clavipes and G. clavariiforme have verrucose peridial cells and different 28S rDNA sequences; G. nidus-avis has rugose peridial cells; and G. corniculans has cornute peridia that dehisce from lateral slits while apices remain intact and verrucose peridial walls with verrucae on the side walls (1). The infection was likely caused by basidiospores originating from telia on Juniperus spp. in the area surrounding the field. However, no telia of G. nelsonii were found on junipers in the immediate vicinity. To our knowledge, this is the first report of G. nelsonii on juneberry in Michigan and the Midwest. Because of the devastating impact of this disease on fruit quality, fungicide programs have been devised for disease control and were effective in 2010. Juneberry growers in the Midwest need to be aware of this disease and monitor their crop carefully for symptoms and signs. References: (1) F. D. Kern. A Revised Taxonomic Account of Gymnosporangium. Pennsylvania State University Press, University Park, 1973. (2) K. Laughlin et al. Juneberry for Commercial and Home Use on the Northern Great Plains. North Dakota State University, Fargo 1996. (3) S. K. Lee and M. Kakishima. Mycoscience 40:121, 1999. (4) G. Mazza and C. G. Davidson. Page 516 in: New Crops. Wiley, New York, 1993.

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Isolation and characterization of cell walls from the mesocarp of mature grape berries (Vitis vinifera)

10.26686/wgtn.12597833.v1 ◽

2020 ◽

Author(s):

KJ Nunan ◽

Ian Sims ◽

A Bacic ◽

SP Robinson ◽

GB Fincher

Keyword(s):

Vitis Vinifera ◽

Cell Walls ◽

Vascular Tissue ◽

Compositional Analysis ◽

Water Soluble ◽

Vitis Vinifera L ◽

Nylon Mesh ◽

Cytoplasmic Material ◽

Isolation And Characterization ◽

Tissue Homogenates

Cell walls have been isolated from the mesocarp of mature grape (Vitis vinifera L.) berries. Tissue homogenates were suspended in 80% (v/v) ethanol to minimise the loss of water-soluble wall components and wet-sieved on nylon mesh to remove cytoplasmic material. The cell wall fragments retained on the sieve were subsequently treated with buffered phenol at pH 7.0, to inactivate any wall-bound enzymes and to dislodge small amounts of cytoplasmic proteins that adhered to the walls. Finally, the wall preparation was washed with chloroform/methanol (1:1, v/v) to remove lipids and dried by solvent exchange. Scanning electron microscopy showed that the wall preparation was essentially free of vascular tissue and adventitious protein of cytoplasmic origin. Compositional analysis showed that the walls consisted of approximately 90% by weight of polysaccharide and less than 10% protein. The protein component of the walls was shown to be rich in arginine and hydroxyproline residues. Cellulose and polygalacturonans were the major constituents, and each accounted for 30-40% by weight of the polysaccharide component of the walls. Substantial varietal differences were observed in the relative abundance of these two polysaccharides. Xyloglucans constituted approximately 10% of the polysaccharide fraction and the remainder was made up of smaller amounts of mannans, heteroxylans, arabinans and galactans.

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