Nematode Assay Section

Raleigh, NC, United States

Nematode Assay Section

Raleigh, NC, United States

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Zeng Y.,North Carolina State University | Zeng Y.,Zhongkai University of Agriculture and Engineering | Ye W.,Nematode Assay Section | Tredway L.,North Carolina State University | And 2 more authors.
Zootaxa | Year: 2012

Twenty-nine species of plant-parasitic nematodes were recovered from 282 soil samples collected from turfgrasses in 19 counties in North Carolina (NC) and 20 counties in South Carolina (SC) during 2011 and from previous collections. These nematodes belong to 22 genera in 15 families, including Belonolaimus longicaudatus, Dolichodorus heterocephalus, Filenchus cylindricus, Helicotylenchus dihystera, Scutellonema brachyurum, Hoplolaimus galeatus, Mesocriconema xenoplax, M. curvatum, M. sphaerocephala, Ogma floridense, Paratrichodorus minor, P. allius, Tylenchorhynchus claytoni, Pratylenchus penetrans, Meloidogyne graminis, M. naasi, Heterodera sp., Cactodera sp., Hemicycliophora conida, Loofia thienemanni, Hemicaloosia graminis, Hemicriconemoides wessoni, H. chitwoodi, Paratylenchus goldeni, Xiphinema americanum sensu lato, X. bakeri, X. chambersi, Longidorus paralongicaudatus, and Aphelenchoides myceliophagus. Eleven species (Meloidogyne graminis, M. naasi, Cactodera sp., Pratylenchus penetrans, Hemicycliophora conida, Hemicaloosia graminis, Mesocriconema xenoplax, M. sphaerocephala, Ogma floridense, Paratrichodorus allius, Dolichodorus heterocephalus) were new records from turfgrass in both states; five (Heterodera sp., Loofia thienemanni, M. curvatum, Longidorus paralongicaudatus, Filenchus cylindricus) were new in SC; and three (Hemicriconemoides wessoni, Xiphinema bakeri, Aphelenchoides myceliophagus) were new in NC. The morphological and morphometric characteristics of these species are presented. Copyright © 2012 · Magnolia Press.

Bursaphelenchus xylophilus, the pine-wood nematode (PWN), is the causal agent of pine wilt disease, one of the most damaging emerging pest problems to forests around the world. It is native to North America where it causes relatively minor damage to native conifers but is labeled an EPPO-A-2 pest and a quarantine nematode for many countries outside of the United States because of its potential for destruction to their native conifers. Exports of wood logs and commodities involving softwood packaging materials now require a lab test for the presence/absence of this regulated nematode species. We characterized the DNA sequences on the ribosomal DNA small subunit, large subunit D2/D3, internal transcribed spacer (ITS) and mitochondrial DNA cytochrome oxidase subunit one on the aphelenchid species and described the development of a real-time-PCR method for rapid and accurate identification of PWN targeting the ITS-1. A total of 97 nematode populations were used to evaluate the specificity and sensitivity of this assay, including 45 populations of B. xylophilus and 36 populations of 21 other species of Bursaphelenchus which belong to the abietinus, cocophilus, eggersi, fungivorus, hofmanni, kevini, leoni, sexdentati, and xylophilus groups and one unassigned group from a total of 13 groups in the genus Bursaphelenchus; 15 populations of Aphelenchoides besseyi, A. fragariae, Aphelenchoides species and Aphelenchus avenae; and one population of mixed nematode species from a soil sample. This assay proved to be specific to B. xylophilus only and was sensitive to a single nematode specimen regardless of the life stages present. This approach provides rapid species identification necessary to comply with the zero-tolerance export regulations.

Esmaeili M.,University of Tehran | Heydari R.,University of Tehran | Ye W.,Nematode Assay Section
Journal of Nematology | Year: 2016

Paurodontella parapitica n. sp., collected from the rhizosphere of an apple tree in Kermanshah province, western Iran, is described. The new species is characterized by a body length of 505 to 723 mm (females) and 480 to 600 mm (males), lip region continuous by depression; 7 to 8 mm broad, 3 to 4 mm high, stylet length 7 to 9 mm or 1 to 1.3 times the lip region diameter, short postuterine sac of 4 to 6 mm long, lateral fields with five to six incisures; outer incisures crenated and inner incisures weakly crenated, excretory pore situated 90 to 100 mmfrom anterior end; functional males common in the population, with spicules 24 to 26 mmlong. Tail of both sexes similar, almost straight and elongate-conoid. The new species resembles in morphology and morphometrics to four known species of the genus, namely P. apitica, P. minuta, P. myceliophaga, and P. sohailai. The results of phylogenetic analyses based on sequences of D2/D3 expansion region of 28S rRNA gene revealed this genus is polyphyletic in four different clades in Tylenchid. © The Society of Nematologists 2016.

Yu Q.,Agriculture and Agri Food Canada | Ye W.,Nematode Assay Section | Powers T.,University of Nebraska - Lincoln
Journal of Nematology | Year: 2016

Gracilacus wuae n. sp. from soil associated with cow parsnip in Ontario, Canada is described and illustrated. Morphologically, females have a long stylet ranging from 80 to 93 mmlong, the lip region not offset from the body contour, without lateral lips but with large and flat submedian lobes, the mouth opening slit-like elongated laterally and surrounded by lateral flaps, the excretory pore is anterior to the knobs of the stylet; males without stylet and the pharynx degenerated. The fourth-stage juveniles lack a stylet, the pharynx degenerated, and can be differentiated into preadult females and males based on the position of the genital primordia. The third-stage juveniles are similar to females but smaller. Phylogenetic studies using the rDNA small subunit 18S, large subunit 28S D2/D3, and internal transcribed spacer (ITS) sequences collectively provide evidence of a grouping with other Gracilacus and some species of Paratylenchus with stylet length of females longer than 41 mm deposited in GenBank. © The Society of Nematologists 2016.

Pedram M.,Tarbiat Modares University | Pourjam E.,Tarbiat Modares University | Robbins R.T.,University of Arkansas | Ye W.,Nematode Assay Section | Pena-Santiago R.,University of Jaén
Nematology | Year: 2011

Rhyssocolpus vinciguerrae sp. n., from natural habitats in Iran, is described, illustrated and sequenced. It is characterised by the body length of 1.04-1.37 mm, lip region offset by depression and 11-13 μm broad, odontostyle 8-10 μm or 0.7-0.8 times the lip region diam. long, neck 227-265 μm long, pharyngeal expansion 80-95 μm long or 31-35% of total neck length, a dorsal cell mass present between cardia and the end of the anterior ovary/testis, uterus bipartite, 90-170 μm long, vulva longitudinal (V = 48-55), abundant irregularities in body cuticle around vulva, female tail conical with rounded terminus (35-55 μm, c = 24-34, c′ = 1.4-1.9), spicules 43-51 μm long and 6-8 spaced ventromedian supplements located outside the range of the spicules. It is very similar to R. aquilonius, R. arcticus and R. iuventutis. A molecular characterisation of the new species was done on ribosomal DNA nearfull-length small subunit 18S gene, internal transcribed spacer and partial 5.8S gene. The results obtained support a close relationship between Rhyssocolpus and Heterodorus, and a more distant relationship with Enchodelus. © 2011 BRILL.

Aliramaji F.,Tarbiat Modares University | Pourjam E.,Tarbiat Modares University | Atighi M.R.,Tarbiat Modares University | Ye W.,Nematode Assay Section | And 2 more authors.
Russian Journal of Nematology | Year: 2014

Ektaphelenchoides poinari sp. n. is described and illustrated based on morphological, morphometric and molecular data. The new species is characterised by females with 477-565 μn long body, offset lip region 7.5-9.5 μrn wide, separated from the rest of the body by a shallow constriction, 18-23 μm long stylet lacking knobs at base, position of excretory pore at the level to slightly posterior of the metacorpus base, three incisures in lateral field, short post-uterine sac (PUS) (0.3-0.4 corresponding body width), posterior end of the body conical, males rare, spicules having rounded condylus, pointed rostrum and blunt end. The new species is close to E. attenuata, E. kelardashtensis, E. musae, E. pini, E. sylvestris and E. winteri, but differs from them by its shorter PUS, shape of posterior body end in females and males, position of vulva and excretory pore and molecular characters. Ektaphelenchoides poinari sp. n. was easily differentiated from other sequenced species by the partial small subunit rRNA gene (SSU), D2D3 expansion segment of the large subunit rRNA gene (LSU) and internal transcribed spacer 1 (ITS1). Phylogenetic analysis with these sequences suggests that E. poinari sp. n. is close to other Ektaphelenchoides species and Devibursaphelenchus. A compendium for valid species based on morphological and morphometric characters is also given.

Atighi M.R.,Tarbiat Modares University | Pourjam E.,Tarbiat Modares University | Pedram M.,Tarbiat Modares University | Ye W.,Nematode Assay Section | And 2 more authors.
Russian Journal of Nematology | Year: 2013

Ektaphelenchoides kelardashtensis sp. n. recovered from bark samples of an unidentified tree in Mazandaran province is described and illustrated based on morphological and molecular characters. The new species is characterised by its body length of 433-577 urn in the females, a slightly off-set head, no apparent lateral field, total stylet length of 13-16 urn, excretory pore at 55-66 urn and hemizonid at 67-78 urn from anterior end, and rare males. The new species comes close in morphology and morphometries to three known species of the genus, namely E. attenuata, E. musae and E. sylvestris mostly by having a long and filiform tail (posterior body). Based on molecular data (the results of the phylogenetic comparisons), it shows more similarity to E. hunti. Compared with E. attenuata, the new species has shorter body, stylet and post-uterine sac and differences in the shape of the male tail and spicules. Compared with E. musae, the new species can be separated by its shorter body, stylet and post-uterine sac, greater index a, more anteriorly located excretory pore and hemizonid and the presence of males. Compared with E. sylvestris, the new species has a shorter stylet, greater index a, more anteriorly located vulva, hemizonid and excretory pore, difference in shape of posterior body and the presence of males. Compared with E. hunti, it has a shorter body, stylet and post-uterine sac, more anteriorly located excretory pore and hemizonid and a different shape of the posterior end. Molecular analyses were performed based on 743 bp partial ribosomal DNA large subunit D2-D3 and showed E. kelardashtensis sp. n. to be unique, but closest to E. hunti.

Pedram M.,Tarbiat Modares University | Pourjam E.,Tarbiat Modares University | Atighi M.R.,Tarbiat Modares University | Ye W.,Nematode Assay Section | Houshmand A.,Tarbiat Modares University
Annales Zoologici | Year: 2012

Ektaphelenchoides sylvestris sp. nov. is described and illustrated. The new species was recovered from the galleries of bark beetles from a dead Pinus sylvestris L. tree and characterized by females with 644843 m long body, lip region 7.59.0 m wide, separated from the rest body with a shallow constriction, stylet 1823 m long, excretory pore 7285 m far from anterior end, postuterine sac short, 511 m long and male absence. By having a short postuterine sac, the new species comes close to four known species of genus namely E. attenuata, E. musae, E. pini and E. wintert. © Fundacja Natura optima dux.

Yu Q.,Agriculture and Agri Food Canada | Gu J.,Technical Center | Ye W.,Nematode Assay Section
Nematology | Year: 2013

Deladenus prorsus n sp, isolated from dunnage wood originating from Malaysia and intercepted in Ningbo port, P.R. China, is described and illustrated. The dunnage wood material appeared to have holes resembling the typical exit holes of wood-boring insects and have associated blue stain. The new species is characterised by the presence of both the mycophagous and infective forms (Deladenus consists of mycetophagous-only forms and those with known female dimorphism), the body length of 814 (670-1147) and 898 (812-979) μm for mycetophagous males and females, respectively, and 1129 (1114-1352) μm for the infective female, and by the very anterior position of the excretory pore which is situated at 30.7 (24.4-33.0), 30.6 (25.4-35.6) and 37.9 (27.3-39.7) μm for the mycetophagous males and females and infective females, respectively, and the distance that the excretory pore is located anterior to the hemizonid which is 82 (77-90), 74 (54-92) and 86 (64-106) μm for the mycetophagous males and females and infective females, respectively. The diagnostic value of the excretory pore and the hemizonid of the species of the genus are discussed. The ribosomal DNA ITS region was sequenced and analysed. © 2013 Koninklijke Brill NV, Leiden.

Soybean cyst nematode (SCN) is an obligate, sedentary parasite that is a major pathogen of soybean and accounts for an estimated 1 billion dollars in production losses annually in the United States of America. This paper describes the development of a real-time PCR method for rapid, sensitive, species-specific and accurate identification of SCN alone or on mixed populations with other nematodes in North Carolina. The 83-bp DNA fragment of PrimeTime-real-time PCR was designed based on a 477-bp- SCN-SCAR marker previously proved to be SCN-specific. A total of 44 populations including cyst forming nematodes (Heterodera glycines, H. fici, H. schachtii, H. trifolii, Cactodera weissi, Globodera tabacum, Meloidodera floridensis and other unidentified cyst nematodes) and non-cyst forming nematodes (Ditylenchus dipsaci, Meloidogyne incognita and Xiphinema chambersi ) were tested in this study, all SCN populations are tested positive and non-SCN populations negative. This assay for the detection and identification has been successfully applied for testing a single SCN cyst, a 2nd-stage-SCN juvenile, a single SCN egg, up to ten SCN cysts, a 10-fold dilution of a single 2nd-stage- SCN juvenile and 20-fold dilution of one SCN cyst. The assay is not SCN-race specific. It gave an accurate positive result when SCN is mixed with other cyst species. Also, nematode universal primers/probes for real-time PCR amplification as a nematode endogenous control to detect the presence of 18S ribosomal RNA (rRNA) gene were employed in this assay, so that a SCN-negative sample can be tested to exclude false negative. This method will be very useful for a broad range of research programs as well as the regulatory response and management of SCN in North Carolina and other region of the southeastern U.S.A. © The Society of Nematologists 2012.

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