Systematics of Hypnea (Cystocloniaceae, Rhodophyta) from coastal North Carolina, with a first report of Calliblepharis saidana from the United States Atlantic Coast

Abstract Complete and/or partial DNA sequences for the plastid-encoded rbcL gene and the 5′ end of the mitochondrial cytochrome oxidase I (COI-5P) gene were used to re-examine the systematics of Hypnea species (Cystocloniaceae, Rhodophyta) from North Carolina, USA. These data, combined with light microscopic observations, indicate that two species (Hypnea cryptica and H. musciformis sensu stricto) are present in nearshore waters of coastal North Carolina. Molecular and morphological analyses with topotype material of Hypnea volubilis from North Carolina offshore waters revealed that it and Calliblepharis saidana are conspecific. Hypnea volubilis is proposed as a heterotypic synonym of C. saidana. This is the first report of Calliblepharis from the United States Atlantic coast and only the second report from the western hemisphere.

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First Report of Meloidogyne enterolobii on Cotton and Soybean in North Carolina, United States

Plant Disease ◽

10.1094/pdis-03-13-0228-pdn ◽

2013 ◽

Vol 97 (9) ◽

pp. 1262-1262 ◽

Cited By ~ 17

Author(s):

W. M. Ye ◽

S. R. Koenning ◽

K. Zhuo ◽

J. L. Liao

Keyword(s):

United States ◽

North Carolina ◽

Dna Sequences ◽

Natural Infection ◽

Large Subunit ◽

The United States ◽

Infested Soil ◽

First Report ◽

Cotton Plants ◽

Plant Pathol

Stunted cotton plants (Gossypium hirsutum L. cvs. PHY 375 WR and PHY 565 WR) from two separate fields near Goldsboro in Wayne County, North Carolina were collected by the NCDA&CS Agronomic Division nematode lab for nematode assay and identification in December 2011. The galls on cotton plants were very large in comparison with those commonly associated with Meloidogyne incognita Kofoid and White (Chitwood) infected cotton. In August 2012, the lab also received heavily galled roots of soybean (Glycine max (L.) Merr. cv. 7732) from Wayne and Johnston counties. Population densities of the 2nd-stage juveniles ranged from 150 to 3,800 per 500 cc soil. Female perineal patterns were similar to M. incognita, but PCR and DNA sequencing matched that of M. enterolobii Yang and Eisenback (4). DNA sequences of ribosomal DNA small subunit, internal transcribed spacer, large subunit domain 2 and 3, intergeneric spacer, RNA polymerase II large subunit, and histone gene H3, were found to be 100% homologous when comparing populations of M. enterolobii from North Carolina and China. Species identification was also confirmed using PCR by a species-specific SCAR primer set MK7-F/MK7-R (2). M. enterolobii Yang & Eisenback was described in 1983 from a population causing severe damage to pacara earpod tree (Enterolobium contortisiliquum (Vell.) Morong) in China (4). In 2004, M. mayaguensis Rammah & Hirschmann, a species described from Puerto Rico, was synonymized with M. enterolobii based on esterase phenotype and mitochondrial DNA sequence (3). M. enterolobii is considered to be a highly pathogenic species and has been reported from vegetables, ornamental plants, guava, and weeds in China, Africa, Central and South America, the Caribbean, and Florida in the United States (1,3,4). Of particular concern is its ability to develop on crop genotypes carrying root-knot-nematode resistance genes (Mi-1, Mh, Mir1, N, Tabasco, and Rk) in tobacco, tomato, soybean, potato, cowpea, sweet potato, and cotton. Consequently, this species was added to the European and Mediterranean Plant Protection Organization A2 Alert list in 2010. Two populations of M. enterolobii one from soybean and one from cotton were reared on tomato (Solanum lycopersicum L. var. lycopersicum) in a greenhouse setting. Eggs were extracted using NaOCl and inoculated, at a rate of 7,000 per 15-cm-diameter clay pot, into a sandy soil mixture (1:1 washed river sand and loamy sand). Tomato, peanut (Arachis hypogaea L.), cotton, watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai), pepper (Capsicum annuum L.), and root-knot-susceptible and -resistant tobacco (Nicotiana tabacum L. cvs. K326 and NC 70, respectively) were transplanted immediately into the infested soil with four replications. Root galls on the host differentials were evaluated after 90 days. Reproduction occurred on all hosts except for peanut, which is consistent with reports for M. enterolobii and M. incognita race 4 (4). Adult females from pepper plants used in the host differential test were sequenced on partial 18S and ITS1 region and confirmed to be M. enterlobii. To our knowledge, this is the first report of a natural infection of North Carolina field crops with M. enterolobii. References: (1) J. Brito et al. J. Nematol. 36:324, 2004. (2) M. S. Tigano et al. Plant Pathol. 59:1054, 2010. (3) J. Xu et al. Eur. J. Plant Pathol. 110:309, 2004. (4) B. Yang and J. D. Eisenback. J. Nematol. 15:381, 1983.

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First Report of Stem Blight Caused by Calonectria colhounii (Anamorph Cylindrocladium colhounii) on Greenhouse-Grown Blueberries in the United States

Plant Disease ◽

10.1094/pdis-02-11-0117 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1187-1187

Author(s):

J. J. Sadowsky ◽

T. D. Miles ◽

A. M. C. Schilder

Keyword(s):

United States ◽

North Carolina ◽

Root Rot ◽

The United States ◽

Vaccinium Corymbosum ◽

Conidial Suspension ◽

Centraalbureau Voor ◽

First Report ◽

Stem Lesions ◽

Β Tubulin

Necrotic stems and leaves were observed on 2- to 4-month-old, rooted microshoot plants (Vaccinium corymbosum L. ‘Liberty’ and ‘Bluecrop’, V. angustifolium Aiton ‘Putte’, and V. corymbosum × V. angustifolium ‘Polaris’) in a Michigan greenhouse in 2008 and 2009. As the disease progressed, leaves fell off and 80 to 100% of the plants died in some cases. Root rot symptoms were also observed. A fungus was isolated from stem lesions. On potato dextrose agar (PDA), cultures first appeared light tan to orange, then rusty brown and zonate with irregular margins. Chains of orange-brown chlamydospores were abundant in the medium. Macroconidiophores were penicillately branched and had a stipe extension of 220 to 275 × 2.5 μm with a narrowly clavate vesicle, 3 to 4 μm wide at the tip. Conidia were hyaline and cylindrical with rounded ends, (1-)3-septate, 48 to 73 × 5 to 7 (average 60 × 5.5) μm and were held together in parallel clusters. Perithecia were globose to subglobose, yellow, 290 to 320 μm high, and 255 to 295 μm in diameter. Ascospores were hyaline, 2- to 3-septate, guttulate, fusoid with rounded ends, slightly curved, and 30 to 88 × 5 to 7.5 (average 57 × 5.3) μm. On the basis of morphology, the fungus was identified as Calonectria colhounii Peerally (anamorph Cylindrocladium colhounii Peerally) (1,2). The internal transcribed spacer region (ITS1 and ITS2) of the ribosomal DNA and the β-tubulin gene were sequenced (GenBank Accession Nos. HQ909028 and JF826867, respectively) and compared with existing sequences using BLASTn. The ITS sequence shared 99% maximum identity with that of Ca. colhounii CBS 293.79 (GQ280565) from Java, Indonesia, and the β-tubulin sequence shared 97% maximum identity with that of Ca. colhounii CBS 114036 (DQ190560) isolated from leaf spots on Rhododendron sp. in North Carolina. The isolate was submitted to the Centraalbureau voor Schimmelcultures in the Netherlands (CBS 129628). To confirm pathogenicity, 5 ml of a conidial suspension (1 × 105/ml) were applied as a foliar spray or soil drench to four healthy ‘Bluecrop’ plants each in 10-cm plastic pots. Two water-sprayed and two water-drenched plants served as controls. Plants were misted intermittently for 2 days after inoculation. After 7 days at 25 ± 3°C, drench-inoculated plants developed necrotic, sporulating stem lesions at the soil line, while spray-inoculated plants showed reddish brown leaf and stem lesions. At 28 days, three drench-inoculated and one spray-inoculated plant had died, while others showed stem necrosis and wilting. No symptoms were observed on control plants. Fungal colonies reisolated from surface-disinfested symptomatic stem, leaf, and root segments appeared identical to the original isolate. Cy. colhounii was reported to cause a leaf spot on blueberry plants in nurseries in China (3), while Ca. crotalariae (Loos) D.K. Bell & Sobers (= Ca. ilicicola Boedijn & Reitsma) causes stem and root rot of blueberries in North Carolina (4). To our knowledge, this is the first report of Ca. colhounii causing a disease of blueberry in Michigan or the United States. Because of its destructive potential, this pathogen may pose a significant threat in blueberry nurseries. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul, MN, 2002. (2) L. Lombard et al. Stud. Mycol. 66:31, 2010. (3) Y. S. Luan et al. Plant Dis. 90:1553, 2006. (4) R. D. Milholland. Phytopathology 64:831, 1974.

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First Report of Pseudoperonospora cubensis Causing Downy Mildew on Momordica balsamina and M. charantia in North Carolina

Plant Disease ◽

10.1094/pdis-03-14-0305-pdn ◽

2014 ◽

Vol 98 (9) ◽

pp. 1279-1279 ◽

Cited By ~ 10

Author(s):

E. Wallace ◽

M. Adams ◽

K. Ivors ◽

P. S. Ojiambo ◽

L. M. Quesada-Ocampo

Keyword(s):

United States ◽

North Carolina ◽

Downy Mildew ◽

Leaf Surface ◽

The United States ◽

Pseudoperonospora Cubensis ◽

Post Inoculation ◽

Bitter Melon ◽

First Report ◽

C Cycle

Momordica balsamina (balsam apple) and M. charantia L. (bitter melon/bitter gourd/balsam pear) commonly grow in the wild in Africa and Asia; bitter melon is also cultivated for food and medicinal purposes in Asia (1). In the United States, these cucurbits grow as weeds or ornamentals. Both species are found in southern states and bitter melon is also found in Pennsylvania and Connecticut (3). Cucurbit downy mildew (CDM), caused by the oomycete Pseudoperonospora cubensis, was observed on bitter melon and balsam apple between August and October of 2013 in six North Carolina sentinel plots belonging to the CDM ipmPIPE program (2). Plots were located at research stations in Johnston, Sampson, Lenoir, Henderson, Rowan, and Haywood counties, and contained six different commercial cucurbit species including cucumbers, melons, and squashes in addition to the Momordica spp. Leaves with symptoms typical of CDM were collected from the Momordica spp. and symptoms varied from irregular chlorotic lesions to circular lesions with chlorotic halos on the adaxial leaf surface. Sporulation on the abaxial side of the leaves was observed and a compound microscope revealed sporangiophores (180 to 200 μm height) bearing lemon-shaped, dark sporangia (20 to 35 × 10 to 20 μm diameter) with papilla on one end. Genomic DNA was extracted from lesions and regions of the NADH dehydrogynase subunit 1 (Nad1), NADH dehydrogynase subunit 5 (Nad5), and internal transcribed spacer (ITS) ribosomal RNA genes were amplified and sequenced (4). BLAST analysis revealed 100% identity to P. cubensis Nad1 (HQ636552.1, HQ636551.1), Nad5 (HQ636556.1), and ITS (HQ636491.1) sequences in GenBank. Sequences from a downy mildew isolate from each Momordica spp. were deposited in GenBank as accession nos. KJ496339 through 44. To further confirm host susceptibility, vein junctions on the abaxial leaf surface of five detached leaves of lab-grown balsam apple and bitter melon were either inoculated with a sporangia suspension (10 μl, 104 sporangia/ml) of a P. cubensis isolate from Cucumis sativus (‘Vlaspik' cucumber), or with water as a control. Inoculated leaves were placed in humidity chambers to promote infection and incubated using a 12-h light (21°C) and dark (18°C) cycle. Seven days post inoculation, CDM symptoms and sporulation were observed on inoculated balsam apple and bitter melon leaves. P. cubensis has been reported as a pathogen of both hosts in Iowa (5). To our knowledge, this is the first report of P. cubensis infecting these Momordica spp. in NC in the field. Identifying these Momordica spp. as hosts for P. cubensis is important since these cucurbits may serve as a source of CDM inoculum and potentially an overwintering mechanism for P. cubensis. Further research is needed to establish the role of non-commercial cucurbits in the yearly CDM epidemic, which will aid the efforts of the CDM ipmPIPE to predict disease outbreaks. References: (1) L. K. Bharathi and K. J. John. Momordica Genus in Asia-An Overview. Springer, New Delhi, India, 2013. (2) P. S. Ojiambo et al. Plant Health Prog. doi:10.1094/PHP-2011-0411-01-RV, 2011. (3) PLANTS Database. Natural Resources Conservation Service, USDA. Retrieved from http://plants.usda.gov/ , 7 February 2014. (4) L. M. Quesada-Ocampo et al. Plant Dis. 96:1459, 2012. (5) USDA. Index of Plant Disease in the United States. Agricultural Handbook 165, 1960.

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First Report of Tobacco ringspot virus in Blackberry (Rubus sp.) in Alabama

Plant Disease ◽

10.1094/pdis-92-12-1708c ◽

2008 ◽

Vol 92 (12) ◽

pp. 1708-1708 ◽

Cited By ~ 3

Author(s):

E. Coneva ◽

J. F. Murphy ◽

R. Boozer ◽

N. Velásquez

Keyword(s):

United States ◽

North Carolina ◽

South Carolina ◽

Virus Infection ◽

The United States ◽

Negative Control ◽

Ringspot Virus ◽

First Report ◽

Tobacco Ringspot Virus ◽

Control Samples

In 2006, primocane stunted growth and crumbly berry development were observed on 4-year-old Kiowa and Apache blackberry cultivars grown at the Chilton Research and Extension Center, Clanton, AL. Samples from affected plants were tested for virus infection by ELISA kits (Agdia, Inc., Elkhart, IN) specific to each of 14 different viruses. Most samples tested positive for Tobacco ringspot virus (TRSV). TRSV was detected in blackberry samples from North Carolina and South Carolina (2). Bray et al. (1) studied the incidence of viruses in blackberry nursery stock in the United States and reported that 9% of the tested samples contained TRSV. Thus, a survey was conducted for TRSV incidence among commercial blackberry stands in eight counties in Alabama during July 2007. Blackberry plants were observed to express virus-like symptoms including chlorotic spots on leaves, leaf veinal chlorosis, stunting, and combinations thereof. Fruit-bearing plants sometimes had crumbly fruit symptoms characteristic of virus infection. Leaf samples that were collected from symptomatic and nonsymptomatic plants representing 14 cultivars were tested by TRSV ELISA (Agdia, Inc.). Of 180 blackberry samples, 68 tested positive for TRSV. Positive ELISA reactions for TRSV were on average 28 times greater than the reactions of known negative control samples considered negative for TRSV. Blackberry plants shown to be infected with TRSV during the 2007 survey were tested in July 2008 in an effort to confirm the presence of TRSV. Fifty-four percent of the samples tested positive by ELISA with the average positive ELISA value being 21 times higher than the average negative ELISA value for known negative control samples. To further confirm the occurrence of TRSV in Alabama-grown blackberry plants, leaf samples were tested by reverse transcription (RT)-PCR to amplify a 329-bp fragment of the viral coat protein gene (TRSV RNA 2 sequence accession no. NC_005096; primers TRSCP-F (5′-TCTGGCACTATAAGCGGAAG-3′) and TRSCP-R (5′-GAAAACATGGGAGGATGCAC-3′). A single band of the anticipated size was amplified (analyzed by agarose gel electorphoresis and visualized by ethidium bromide staining) from RNA samples extracted with a RNeasy Mini kit (Qiagen, Valencia, CA) from blackberry samples that tested positive for TRSV by ELISA and a known positive control. No amplified product resulted from a blackberry sample that tested negative for TRSV by ELISA. These results illustrate and confirm the presence of TRSV in blackberry leaf tissues grown in Alabama. To our knowledge, this is the first report of TRSV infection of blackberry plants in Alabama. References: (1) M. M. Bray et al. HortScience 40:874, 2005. (2) T. L. Guzmán-Baeny. Incidence, distribution, and symptom description of viruses in cultivated blackberry (Rubus subgenus Eubatus) in the southeastern United States. M.S. thesis, North Carolina State University, Raleigh, 2003.

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First Report of Curvularia Blight of Zoysiagrass Caused by Curvularia lunata in the United States

Plant Disease ◽

10.1094/pdis-92-1-0173b ◽

2008 ◽

Vol 92 (1) ◽

pp. 173-173 ◽

Cited By ~ 2

Author(s):

J. A. Roberts ◽

L. P. Tredway

Keyword(s):

United States ◽

North Carolina ◽

Morphological Characteristics ◽

Microscopic Analysis ◽

The United States ◽

Curvularia Lunata ◽

One Pot ◽

Plastic Container ◽

First Report ◽

Initial Symptoms

Symptoms of an unknown foliar blight have been observed in zoysiagrass (Zoysia matrella, Z. japonica, and hybrids) landscapes in North Carolina since 2002. Disease activity is most common during spring and summer when temperatures are between 21 and 30°C. Affected leaves initially exhibit small, chocolate brown spots, followed by dieback of leaves from the tips, and eventually blighting of entire tillers. Symptoms appear in small, irregular patches as much as 15 cm in diameter, but numerous patches may coalesce to impact large sections of turf. Infected turf appears tan or brown from a distance, but often turns black during periods of wet or humid weather. Microscopic analysis revealed profuse sporulation of Curvularia spp. on the surface of symptomatic leaves. Leaf sections were surface disinfested in 10% Clorox for 1 to 2 min, blotted dry, then plated on potato dextrose agar (PDA) containing 50 mg/l of tetracycline, streptomycin, and chloramphenicol. Twenty-eight fungal isolates were obtained from six locations. Examination of conidia produced in culture revealed 21 isolates of Curvularia, two isolates of Drechslera, one isolate of Nigrospora, and four unidentified sterile fungi. Curvularia isolates were identified to species on the basis of morphological characteristics (1) and ITS-rDNA sequences. Known isolates of C. eragrostidis, C. geniculata, C. inequalis, C. lunata, C. pallescens, and C. trifolii were obtained from the American Type Culture Collection for comparison. All unknown isolates produced conidia that were characteristic of C. lunata (lacking a protuberant hilum, smooth walled, tri-septate, predominantly curved, and mid- or dark brown, average dimensions 17 to 25 × 8 to 12 μm). Colonies on PDA lacked stroma or the zonate appearance indicative of C. lunata var. aeria. The pathogenicity of C. lunata isolates was tested on zoysiagrass cvs. El Toro (Z. japonica) and Emerald (Z. japonica × matrella). Cores (11.4 cm in diameter) of established zoysiagrass were potted in calcined clay (Turface Allsport; Profile Products LLC, Buffalo Grove, IL), and transferred to a greenhouse where the average temperature was 26°C. Five isolates were selected to represent the geographic range of Curvularia blight in North Carolina, and conidia were produced on PDA under continuous fluorescent illumination. Each isolate was inoculated to one pot of each zoysiagrass variety by spraying with 25 ml of a suspension containing 2 × 105 conidia/ml with an airbrush. Inoculated pots were placed in a sealed, nontransparent plastic container for 48 h at 28°C to encourage infection and then transferred back to the greenhouse bench. Pathogenicity tests were repeated four times over time. Isolates ZFB3 and ZFB28 were most virulent with initial symptoms of foliar dieback appearing within 1 week after inoculation. Continued disease progress resulted in necrosis of the entire plant. Other isolates induced symptoms within 2 to 3 weeks after inoculation; however, disease severity was lower as compared with ZFB3 and ZFB28 throughout each experiment. Cvs. Emerald and El Toro were equally susceptible to infection by C. lunata. To our knowledge, this is the first report of Curvularia blight of zoysiagrass in the United States. This disease was previously described in Japan where it is commonly referred to as ‘dog footprint’ (3) and Brazil (2). References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) F. B. Rocha et al. Australas. Plant Pathol. 33:601, 2004. (3) T. Tani and J. B. Beard. Color Atlas of Turfgrass Diseases. Ann Arbor Press, Chelsea, MI, 1997.

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First Report of Coleosporium helianthi infecting Helianthus verticillatus (Whorled Sunflower)in the United States

Plant Disease ◽

10.1094/pdis-11-21-2496-pdn ◽

2021 ◽

Author(s):

Robert N. Trigiano ◽

Sarah L. Boggess ◽

Michelle Odoi ◽

Denita Hadziabdic ◽

Ernest C. Bernard ◽

...

Keyword(s):

United States ◽

Dna Sequences ◽

The United States ◽

Control Measures ◽

Control Treatment ◽

Adaxial Side ◽

Adaxial Surface ◽

First Report ◽

Leaf Surfaces ◽

Pinus Spp

Helianthus verticillatus, the whorled sunflower, is an endangered species found only in the southern United States (Trigiano et al. 2021) that is being developed for ornamental uses. This sunflower species requires little to no maintenance, produces spectacular floral displays from September into October, and attracts numerous potential pollinators including many native bees (Strange et al. 2020). In June and July of 2021, chlorotic, irregularly shaped spots were observed on the adaxial surface of mature leaves of two vegetatively produced clones of H. verticillatus (Trigiano et al., 2021) at three locations in Knoxville, TN. In September, yellow (4A, Royal Horticultural Society Color Chart) sori were abundant on abaxial surfaces and more rarely on the adaxial leaf surfaces of both clones at all locations. Globose-to-cylindrical, yellow urediniospores were 23.7µm (20-32) x 18.9 (16-22) µm (n = 30) with irregular, verrucose ornamentation. The morphology and dimensions of the urediniospores were similar to other Coleosporium species (e.g., C. asterum, Back et al., 2014). Telia were waxy, red-brown (167A; B) and developed in October with colder temperatures. Cylindrical teliospores were sessile, 1-celled, thin-walled with basidia ca. 93 µm (70-117) x 25 µm (19-29), consistent with spores of C. helianthi (Cummins, 1978). DNA was obtained from urediniospores using a Phire kit (ThermoFisher Scientific, Waltham, MA) and the 28S rDNA region was amplified using the NL1 and NL4 primers (Back et al. 2014) (Genbank accession # OL364847) as well as ITS 1-4 primers (White et al. 1990) (GenBank accession OL364848). For comparison, DNA sequences were also obtained from authentic C. helianthi on H. divaricatus in the Arthur Fungarium at Purdue University (#PURN11678; GenBank accession OL364846) using the protocols of Aime et al. (2018). 28S sequences shared 99.65% (568/570 bp) identity. To test Koch’s postulates, seven healthy detached leaves were lightly brushed on both leaf surfaces with leaves with uredia producing urediniospores. The leaves were incubated adaxial side up in 9-cm-diameter Petri dishes on moistened filter paper at ambient laboratory conditions. A similar number of healthy leaves were brushed with healthy leaves, incubated in the laboratory and served as the control treatment. After 7-10 days, uredia with urediniospores formed primarily on the abaxial leaf surface, but a few were present on the adaxial surface of leaves treated with urediniospores, whereas the leaves in the control remained healthy. Molecular, morphological and infectivity studies identified C. helianthi as the pathogen. Coleosporium helianthi occurs on the commercial sunflower, H. annuus, and several wild sunflower species, including H. tuberosum (Jerusalem artichoke) and H. microcephalus (small-headed sunflower), among others in the southern U.S. (Farr and Rossman 2021). Coleosporium species are heteroecious and mostly macrocyclic rusts (McTaggart and Aime, 2018) with aecia and aeciospores typically found on pines (Pinus spp.). Although H. verticillatus is very susceptible to rust infection and it probably reduces photosynthetic capability, it does not appear to adversely affect flowering in the fall. The disease primarily degrades the aesthetic appeal of the plant but does not require control measures. To our knowledge, this is the first report of C. helianthi infecting H. verticillatus. Voucher material is deposited in the Arthur Herbarium (#PURN23470).

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First Report of Puccinia coronata var. coronata sensu stricto Infecting Alder Buckthorn in the United States

Plant Health Progress ◽

10.1094/php-01-17-0003-br ◽

2017 ◽

Vol 18 (2) ◽

pp. 84-86

Author(s):

Shawn C. Kenaley ◽

Geoffrey Ecker ◽

Gary C. Bergstrom

Keyword(s):

United States ◽

North America ◽

Host Range ◽

Geographic Distribution ◽

Phylogenetic Analyses ◽

Rust Fungus ◽

The United States ◽

Sensu Stricto ◽

Puccinia Coronata ◽

First Report

Field symptoms, host distribution, pathogen morphology, and phylogenetic analyses clearly demonstrated that the rust fungus infecting alder buckthorn in Connecticut is Puccinia coronata var. coronata sensu stricto. To our knowledge, this is the first report and confirmation of P. coronata var. coronata s.s. in the United States. Additional collections from purported aecial and telial hosts of P. coronata var. coronata s.s. are necessary to determine its host range, geographic distribution, and incidence within the United States and elsewhere in North America.

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Nivalenol-Type Populations of Fusarium graminearum and F. asiaticum Are Prevalent on Wheat in Southern Louisiana

Phytopathology ◽

10.1094/phyto-03-10-0067 ◽

2011 ◽

Vol 101 (1) ◽

pp. 124-134 ◽

Cited By ~ 118

Author(s):

Liane Rosewich Gale ◽

Stephen A. Harrison ◽

Todd J. Ward ◽

Kerry O'Donnell ◽

Eugene A. Milus ◽

...

Keyword(s):

United States ◽

North Carolina ◽

Fusarium Graminearum ◽

Gulf Coast ◽

Pcr Primers ◽

The United States ◽

Sensu Stricto ◽

Head Blight ◽

Trichothecene Mycotoxin ◽

Southern Louisiana

U.S. populations of the Fusarium graminearum clade cause head blight on wheat and barley and usually contaminate grain with the trichothecene mycotoxin deoxynivalenol (DON). Recently, however, individual nivalenol (NIV)-type isolates from the United States were described that belonged to either the newly described species F. gerlachii or the genetically distinct Gulf Coast population of F. graminearum sensu stricto (s.s.). Here, we describe the discovery of NIV-type F. graminearum s.s. populations that were found in high proportion (79%) among isolates from small-grain-growing regions of Louisiana. We genotyped 237 isolates from Louisiana with newly developed polymerase chain reaction (PCR) restriction fragment length polymorphism markers and multiplex PCR primers that distinguish among the three trichothecene types: the two DON types (15ADON and 3ADON) and NIV. These isolates were compared with 297 isolates from 11 other U.S. states, predominantly from the Midwest. Using Bayesian-model-based clustering, we discovered a southern Louisiana population of F. graminearum s.s. that was genetically distinct from the previously recognized pathogen population in the Midwest (MW15ADON population). Population membership was correlated with trichothecene type. Most isolates from the southern Louisiana population were of the NIV type, while the majority of the isolates from the Midwest were of the 15ADON type. A smaller proportion of isolates from Louisiana belonged to the previously described Gulf Coast population that was mostly of the 3ADON type. The NIV type was also identified in collections from Arkansas (12%), North Carolina (40%), and Missouri (2%), with the collections from Arkansas and North Carolina being small and unrepresentative. F. asiaticum was detected from the two southern Louisiana parishes Acadia and Alexandria. All identified 41 F. asiaticum isolates were of the NIV type. Greenhouse tests indicated that U.S. NIV types accumulated four times less trichothecene toxin than DON types on inoculated wheat. This is the first report of NIV-type populations of F. graminearum s. s. and F. asiaticum in the United States.

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First Report of Stigmina lautii in the United States

Plant Disease ◽

10.1094/pdis.2002.86.6.699a ◽

2002 ◽

Vol 86 (6) ◽

pp. 699-699

Author(s):

C. S. Hodges

Keyword(s):

United States ◽

North Carolina ◽

Plant Disease ◽

The United States ◽

New Host ◽

Decay Fungi ◽

First Report ◽

Blue Spruce ◽

Western North Carolina ◽

Needle Blight

In June 1999, a specimen of blue spruce (Picea pungens) from Avery County, North Carolina, exhibiting symptoms of needle blight was submitted to the Plant Disease and Insect Clinic at North Carolina State University. A fungus sporulating profusely on symptomatic needles was identified as Stigmina lautii. Since then, three additional specimens have been received—on blue spruce from Ashe County, on Norway spruce (P. abies) from Avery County, and on Picea sp. from Cherokee County. These counties are all in western North Carolina but are not contiguous, indicating that the fungus is probably widespread in the western part of the state. S. lautii was described by Sutton (2) in 1973 on black spruce (P. mariana) and white spruce (P. glauca) collected from various locations in Manitoba and Saskatchewan, Canada. The only other reference found to the fungus is a specimen collected in British Columbia, Canada, on P. glauca in 1972 (2). The morphology of the North Carolina specimens of S. lautii is essentially as described by Sutton. The dark brown, superficial, flattened sporodochia are developed only through stomata. Sporodochia are found both on symptomatic needles as well as on adjacent green needles. Conidiophores arise only laterally from the lower, outer cells of the sporodochium, and are macronematous, mononematous, brown, smooth, unbranched, 1 to 2 septate, and 10 to 20 × 4 to 6 μm. Conidiogenous cells are brown, monoblastic, integrated, terminal, percurrent with 3 to 4 annelations, and 6 to 12 × 4 to 5 μm. Conidia are pale brown, cylindrical to fusiform, often curved, thick walled, verrucose, 5 to 8 distoseptate, and 25 to 45 × 5 to 6 μm. Superficially, the sporodochia of S. lautii might be confused with pycnidia of Rhizosphaera kalkhoffii, which also arise through stomata. The latter fungus also is associated with a needle blight of Picea spp. in western North Carolina. Both fungi were present on one specimen examined. Currently, no information is available on the pathogenicity of S. lautii, but its association with typical needle blight symptoms and the known pathogenicity of other Stigmina spp. on conifers make it likely that the fungus is pathogenic to spruce. To my knowledge, this is the first report of S. lautii in the United States, and P. pungens and P. abies represent new host records for the fungus. Specimens BPI 747910 and 840959, have been deposited in the herbarium of the National Fungus Collections, Beltsville, MD. References: (1) J. H. Ginns. Page 158 in: Compendium of Plant Disease and Decay Fungi in Canada 1960-1980. Agric. Can. Publ. 1813, 1986. (2) B. C. Sutton. Mycol. Pap. 132:113, 1973.

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First Report of Root Rot Caused by Fusarium solani on Benincasa hispida in the United States

Plant Disease ◽

10.1094/pdis-06-11-0494 ◽

2012 ◽

Vol 96 (2) ◽

pp. 294-294 ◽

Cited By ~ 2

Author(s):

P. Ji ◽

J. Yin ◽

K. L. Jackson

Keyword(s):

United States ◽

Dna Sequences ◽

Root Rot ◽

Morphological Characteristics ◽

The United States ◽

First Report ◽

Benincasa Hispida ◽

Field Samples ◽

Vegetable Farm ◽

Wax Gourd

Root rot was observed on wax gourd (Benincasa hispida (Thunb.) Cogn.) cv. Black Giant in August 2010 in a commercial vegetable farm in southern Georgia. Approximately 5% of the plants were affected and infected roots turned light to dark brown with partial or entire roots affected and the lower leaves became wilted. Symptomatic roots from six plants were surface sterilized with 0.6% sodium hypochlorite and plated on potato dextrose agar (PDA) medium. Pure cultures had white mycelia and spore masses and were obtained from all six plants by subculturing hyphal tips onto PDA. One- to two-celled, oval- to kidney-shaped microconidia and cylindrical macroconidia with two or three cells plus apical and basal cell were produced, which averaged 12.5 × 4 μm and 28 × 4.5 μm, respectively. Microconidia were abundant and macroconidia were sparse on PDA. Single-spore isolates were obtained and identified as a Fusarium sp. by PCR analysis with primers ITS-Fu-f and ITS-Fu-r (1). Genomic DNA of two isolates obtained from different plants was extracted and a portion of the translation elongation factor 1-α (TEF) gene of the isolates was amplified and sequenced (3). When compared with sequences available in the GenBank database, DNA sequences of the two isolates (GenBank Accession No. JF928376) shared 100% sequence identity with F. solani strain FRC S1734 (GenBank Accession No. DQ247527). The fungus was identified as F. solani (Mart.) Sacc. based on molecular analysis and morphological characteristics (2). Oat grains were separately infected with two isolates, BG2a and BG6, and used to inoculate healthy, 3-week-old wax gourd seedlings (cv. Black Giant) under greenhouse conditions (14-h photoperiod, 24 to 30°C). Each seedling was grown in a 10-cm pot containing a commercial potting mix, and five healthy plants were inoculated with each isolate by placing 15 infected oat grains around each plant at a depth of 5 cm in the soil. Five plants treated with noninfected oat grains served as controls. Symptoms identical to those on field samples developed on all inoculated plants 3 weeks after inoculation but not on the control plants. F. solani was reisolated from inoculated symptomatic plants and the identity was confirmed, which completed Koch's postulates. The experiment was repeated one more time under similar conditions. To our knowledge, this is the first report of root rot caused by F. solani on wax gourd in the United States. Wax gourd is an important specialty crop in the southeastern United States and the occurrence of this disease needs to be taken into account in wax gourd production. References: (1) K. A. Abd-Elsalam et al. Afr. J. Biotechnol. 2:82, 2003. (2) C. Booth. Fusarium Laboratory Guide to the Identification of the Major Species. CMI, Kew, England, 1977. (3) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004.

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