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Wilfrida Decraemer - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterisation of some stubby root nematodes (Nematoda: Trichodoridae) from the USA and other countries
Nematology, 2019Co-Authors: Sergei A. Subbotin, Ignacio Cid Del Prado Vera, Renato N. Inserra, Vladimir N. Chizhov, Wilfrida DecraemerAbstract:The stubby root nematodes are world-wide distributed polyphagous root ectoparasites and can cause damage to a wide range of crops and natural vegetation. In this study, 22 valid and putative species of stubby root nematodes were identified in 37 samples collected in Malaysia, Mexico, Russia, and the USA (California, Florida, Minnesota and Nevada). The analysis of 58 new sequences of the D2-D3 expansion fragments of 28S rRNA gene revealed the following species: Nanidorus minor from California, Florida and Mexico, N. renifer from Florida, two unidentified Nanidorus species from California and Malaysia, respectively, Paratrichodorus allius from Florida and Minnesota, P. pachydermus and Paratrichodorus sp. from Russia, Trichodorus californicus, T. intermedius, and T. obscurus from California, T. obtusus from Florida, eight unidentified Trichodorus species from California, one unidentified Trichodorus species from Nevada, and two unidentified species of stubby root nematodes, one of Trichodorus and another undetermined species from Mexico. Molecular characterisation of T. californicus, T. intermedius and T. obscurus is given for the first time. The phylogenetic tree reconstructed from the analysis of 108 D2-D3 of 28S rRNA gene sequences of 58 valid and putative species of the stubby root nematodes contained five major clades: i) Trichodorus from Europe, Asia and North America; ii) Nanidorus and Trichodorus from Asia; iii) Trichodorus from California; iv) Paratrichodorus from several distant geographical regions; and v) Monotrichodorus from Central and South America. It has been hypothesised that the California Floristic Province is one of the centres of origin and diversification of stubby root nematodes. There is no information on the economic importance of the stubby root nematode species found in California and Mexico. The confirmation of the occurrence of N. renifer and P. allius in Florida should be of concern for the blueberry and potato industries in the state.
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Systernatics of the Trichodoridae (Nematoda) with keys to their species
2015Co-Authors: Wilfrida DecraemerAbstract:Keys are given for the identification of species in the Trichodoridae, partly based on the keys of Loof (1975) and Siddiqi (1974). Recent additions are included and for al1 species a drawing is given of the structure referred to in the key. The genus Paratrichodorus and the diagnostic value of the subgenera Paratrichodorus, Atlantadorus and Nanidorus are discussed. R É S U M B Systématique des Trichodoridae (Nematoda) et clés de détermination des espèces L’auteur propose de nouvelles clés de détermination des espèces de Trichodoridae fondées sur les clés de Loof (1975) et de Siddiqi (1974), et tenant compte des données les plus récentes. Des illustrations sont fournies pour les caractères les plus importants de chaque espèce. Le genre Paratrichodorus et, la,valeur des sous-genres Paratricho-dorus, Atlantadorus et Nanidorus sont discutés. The Trichodoridae are economically, a very important group of nematodes as ectoparasites on the roots of many crop plants and as vectors of tobacco rattle virus and pea early browning virus. Despite the ease with which nematodes can acquire viruses from plants there are rela-tively few vectors. Of some 35 species of Tricho-doridae, a t least eleven transmit tobra-viruses (Hooper, 1973), so identification to species level may be very important. During my study on Trichodoridae 1 came across several inadequacies in available descrip-tions and keys; these changes, together with recent additions made i t necessary t o modify the Beys of Loof (1975) and Siddiqi (1974). For al1 the species 1 have included a drawing of the structure referred to in the key
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Erratum to: First report of stubby root nematode, Paratrichodorus teres (Nematoda: Trichodoridae) from Iran
Australasian Plant Disease Notes, 2015Co-Authors: R. Heydari, Z. Tanha Maafi, F. Omati, Wilfrida DecraemerAbstract:The authors regret that the Iranian specimens of Paratrichodorus teres were incorrectly assigned as holotypes and paratypes in the above paper. The second page, last paragraph should read as follows: BPermanent slides of P.teres females (N=9: slides TPT001 and TPT002) were deposited at the Nematode Collection of the Department of Plant Protection, Karaj, Iran and (N=7: slides 35GO 1 and 35GO 2) at the National Nematode Collection of the Nematology Department, Iranian Research Institute of Plant protection, Tehran, Iran. Additional slides of P. teres females (N=8: slides RIT822, RIT823 and RIT824) were deposited at the nematode collection of Royal Belgian Institute of Natural Sciences, Brussels, Belgium.^
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Phylogenetic relationships, based on SSU rDNA sequences, among the didelphic genera of the family Trichodoridae from Portugal
Nematology, 2010Co-Authors: Isabel Duarte, Derek J. F. Brown, R. Neilson, M. T. M. Almeida, Isabel Marques, Wilfrida DecraemerAbstract:A survey of virus vector trichodorid nematodes was carried out in the central and northern regions of Portugal. Morphobiometric identification showed the presence of trichodorid species previously reported from Portugal, except for Paratrichodorus porosus, which is reported for the first time in Continental Europe. Small subunit ribosomal DNA (SSU rDNA) sequences of ten different species occurring in Portugal were obtained and a phylogenetic analysis based on their alignment was performed to infer relationships among the different Portuguese trichodorid species and three non-indigenous populations (Nanidorus minor, P. allius and P. teres). The resulting phylogenetic tree is in agreement with the currently accepted classification for Trichodoridae, except for Nanidorus, which clusters together with Trichodorus species, while the genera Paratrichodorus and Trichodorus appear as two distinct groups. A better understanding of the generic groupings in the family Trichodoridae was found. Based on the new molecular analyses we herein accept Nanidorus as a valid genus.
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Paratrichodorus divergens sp. n., a new potential virus vector of tobacco rattle virus and additional observations on P. hispanus Roca & Arias, 1986 from Portugal (Nematoda: Trichodoridae).
Nematology, 2005Co-Authors: M. T. M. Almeida, Maria Susana Newton De Almeida Santos, Isabel Abrantes, Wilfrida DecraemerAbstract:During a survey of trichodorids in continental Portugal, a new trichodorid species, Paratrichodorus divergens sp. n., was found. It is described and illustrated with specimens from the type locality together with additional morphometric data and photographs of specimens obtained from soil samples collected in seven other localities. The species is characterised in the female by distinct drop-like to triangular oblique vaginal sclerotisations diverging outwards and sperm cells usually distributed all through the uteri, and in the male by thin, almost straight, striated spicules, the two posteriormost precloacal supplements being located relatively close to one another and usually opposite the distal third of the retracted spicules, presence of a slightly bilobed cloacal lip and sperm cells with a sausage-shaped nucleus. Paratrichodorus divergens sp. n. most closely resembles P. hispanus Roca & Arias, 1986 with which it often occurs in mixed populations. Additional information is also provided for P. hispanus. Coding of the features of the new species is given following the identification key of Decraemer and Baujard.
Derek J. F. Brown - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic relationships, based on SSU rDNA sequences, among the didelphic genera of the family Trichodoridae from Portugal
Nematology, 2010Co-Authors: Isabel Duarte, Derek J. F. Brown, R. Neilson, M. T. M. Almeida, Isabel Marques, Wilfrida DecraemerAbstract:A survey of virus vector trichodorid nematodes was carried out in the central and northern regions of Portugal. Morphobiometric identification showed the presence of trichodorid species previously reported from Portugal, except for Paratrichodorus porosus, which is reported for the first time in Continental Europe. Small subunit ribosomal DNA (SSU rDNA) sequences of ten different species occurring in Portugal were obtained and a phylogenetic analysis based on their alignment was performed to infer relationships among the different Portuguese trichodorid species and three non-indigenous populations (Nanidorus minor, P. allius and P. teres). The resulting phylogenetic tree is in agreement with the currently accepted classification for Trichodoridae, except for Nanidorus, which clusters together with Trichodorus species, while the genera Paratrichodorus and Trichodorus appear as two distinct groups. A better understanding of the generic groupings in the family Trichodoridae was found. Based on the new molecular analyses we herein accept Nanidorus as a valid genus.
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The ultrastructure of the feeding apparatus and pharyngeal tract of four European species of Trichodoridae (Nematoda: Triplonchida)
Nematology, 2004Co-Authors: Eirini Karanastasi, Wilfrida Decraemer, Urs Wyss, Derek J. F. BrownAbstract:Virus-vector plant-parasitic Paratrichodorus and Trichodorus nematodes acquire Tobravirus particles whilst ingesting root cell sap from virus-infected plants and these particles are specifically retained by being adsorbed on to the cuticle lining the wall of the nematode pharyngeal lumen. The feeding apparatus and pharyngeal ultrastructure of four trichodorid virus-vector species were examined to identify the occurrence of any structural characters that could account for particle retention at specific sites in this region. Similarities between Paratrichodorus and Trichodorus species are reported for the first time and new evidence is provided on the position of all gland sinuses and outlets. The occurrence of an inner spear in adult specimens is discussed.
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Molecular diagnostics of some trichodorid nematodes and associated Tobacco rattle virus
Plant Pathology, 2004Co-Authors: K. Boutsika, Derek J. F. Brown, Mark S. Phillips, Stuart A. Macfarlane, R. C. Holeva, Vivian C. BlokAbstract:Several Paratrichodorus and Trichodorus (trichodorid) nematode species are natural vectors of Tobacco rattle virus (TRV) and cause economically important diseases, especially in potato and ornamental bulbous crops. Identification of trichodorid species based on morphological characters is laborious, time-consuming, and requires the services of highly trained personnel. Molecular diagnostics for trichodorid nematodes, using the ribosomal DNA repeat unit, were successfully developed to distinguish two Paratrichodorus and two Trichodorus species. The complete sequences of the 18S genes and the ITS-1 regions for these species were obtained and species-specific primers successfully designed for them. An RT-PCR assay was developed utilizing isolate-specific primers that amplify serologically distinguishable strains of TRV in individual trichodorid nematodes. The primers were based on the highly conserved RNA-1 segment of the bipartite genome and also on different parts of the RNA-2 segment of the virus genome.
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Molecular characterisation of the ribosomal DNA of Paratrichodorus macrostylus, P. pachydermus, Trichodorus primitivus and T. similis (Nematoda: Trichodoridae)
Nematology, 2004Co-Authors: Konstantina Boutsika, Derek J. F. Brown, Mark S. Phillips, Vivian C. BlokAbstract:Trichodorids are plant-ectoparasitic nematodes, causing economically important diseases in many crops. In this study, we characterised ribosomal DNA (rDNA) of four trichodorid species from two different genera (i.e., Paratrichodorus macrostylus, P. pachydermus, Trichodorus primitivus and T. similis). Sequence data from the 18S and 5.8S genes showed high similarity; in contrast, sequence data from the internal transcribed spacer regions (ITS) were highly variable. Sequence divergence between the two genera included many insertions and deletions. Trichodorus primitivus and T. similis ITS regions of 1537 and 1303 bp, respectively, are the longest reported to date in the Phylum Nematoda. Further exploration of the sequence data indicated perfect and non-homologous repeats which were confined to the middle of the ITS regions.
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Interspecific differences in the fine structure of the body cuticle of Trichodoridae Thorne, 1935 (Nematoda: Diphtherophorina) and review of anchoring structures of the epidermis
Nematology, 2001Co-Authors: Eirini Karanastasi, Wilfrida Decraemer, M. T. M. Almeida, Jingwu Zheng, Derek J. F. BrownAbstract:Examination of the fine structure of the body cuticle of Trichodorus cylindricus , T. nanjingensis, T. pakistanensis , T. primitivus, Paratrichodorus anemones , P.hispanus , P.minor , P.pachydermus , P.porosus and P.teres revealed three distinct types, each characterised by differences in layers 4 to 6. A new description is provided for layer 5 and the presence of intracuticular canals and hemidesmosomes as types of anchoring structures for the epidermis are discussed.
R. Neilson - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic relationships, based on SSU rDNA sequences, among the didelphic genera of the family Trichodoridae from Portugal
Nematology, 2010Co-Authors: Isabel Duarte, Derek J. F. Brown, R. Neilson, M. T. M. Almeida, Isabel Marques, Wilfrida DecraemerAbstract:A survey of virus vector trichodorid nematodes was carried out in the central and northern regions of Portugal. Morphobiometric identification showed the presence of trichodorid species previously reported from Portugal, except for Paratrichodorus porosus, which is reported for the first time in Continental Europe. Small subunit ribosomal DNA (SSU rDNA) sequences of ten different species occurring in Portugal were obtained and a phylogenetic analysis based on their alignment was performed to infer relationships among the different Portuguese trichodorid species and three non-indigenous populations (Nanidorus minor, P. allius and P. teres). The resulting phylogenetic tree is in agreement with the currently accepted classification for Trichodoridae, except for Nanidorus, which clusters together with Trichodorus species, while the genera Paratrichodorus and Trichodorus appear as two distinct groups. A better understanding of the generic groupings in the family Trichodoridae was found. Based on the new molecular analyses we herein accept Nanidorus as a valid genus.
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Selective recovery of the virus-vector trichodorid nematode Paratrichodorus anemones from soil samples by immunomagnetic capture
European Journal of Plant Pathology, 2008Co-Authors: R. C. Holeva, D. J. F. Brown, R. H. C. Curtis, R. NeilsonAbstract:Lectins and polyclonal antiserum that bind specifically and reproducibly to the overall surface of Paratrichodorus anemones were identified and bound to monodisperse superparamagnetic particles (Dynabeads) to assess their efficiency as probes for capturing target nematodes from test suspensions. In recovery experiments, while both types of probe isolated nematodes, antibody-coated beads recovered them more efficiently than beads coated with lectins. When immunomagnetic capture was used to isolate P. anemones from mixtures of naturally occurring populations of nematodes extracted in bulk, from soil samples, 80% of the target nematodes were recovered.
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Molecular identification of two stubby root nematode species
American Journal of Potato Research, 2007Co-Authors: Ekaterini Riga, Eirini Karanastasi, C. Marcelo, G. Oliveira, R. NeilsonAbstract:Los nematodos que causan la raíz tocón son de creciente importancia para la industria papera en el Pacífico Noroeste (PNW) de EUA porque transmiten el Tobacco rattle virus (TRV), agente causal del anillo corchoso. En el PNW, el Paratrichodorus allius es el más importante vector del TRV en las áreas de cultivo de papa. También está presente en ciertas partes del PNW P. teres , una especie relacionada. P. allius y P. teres son morfológicamente similares, por lo que crean problemas para una identificación de rutina. Algunos estudios han utilizado técnicas moleculares para identificar las especies pertenecientes a los Trichodoridae. Los iniciadores de PCR en reversa, específicos para ambas especies de Paratrichodorus han sido diseñados y localizados en la región ITS-1 rADN y usados en combinación de un iniciador en la región 18S rADN. La confiabilidad del iniciador fue confirmada en un tamizado in vitro de diferentes poblaciones de P. allius y en análisis in silico de P. teres , sobre las respectivas especies objetivo. Más aún, la especificidad fue demostrada por ausencia de reacciones cruzadas con una gama de especies de nematodos parásitos de plantas típicas de las áreas de cultivo de papa en el PNW. Ha sido desarrollada una prueba de PCR doble que fue más efectiva para la detección de simultánea de ambas especies de Paratrichodorus . Stubby root nematodes are of increasing importance to the potato industry in the Pacific Northwest (PNW) of the USA as they transmit Tobacco rattle virus (TRY), the causal agent of corky ringspot disease. In the PNW, Paratrichodorus allius is the most prevalent TRV vector nematode species in potato growing areas. A closely related species, P. teres , is also found in parts of the PNW. P. allius and P. teres are morphologically similar, thus creating problems for routine identification. Few studies have utilized molecular techniques to identify species belonging to the Trichodoridae. Species-specific reverse PCR primers for both Paratrichodorus species were designed and located in the ITS-1 rDNA region and used in combination with a universal nematode forward primer located in the 18S rDNA. Primer reliability was confirmed by in vitro screening of different P. allius populations and in silico analysis of P. teres on the respective target species. Furthermore, specificity was demonstrated by the absence of cross-reactions with a range of common plant-parasitic nematode species typical of potato growing areas in the PNW. A duplex PCR test was developed that was effective for simultaneous detection of both target Paratrichodorus species.
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Real-time PCR detection and quantification of vector trichodorid nematodes and Tobacco rattle virus.
Molecular and cellular probes, 2006Co-Authors: R Holeva, R. Neilson, K. Boutsika, D. J. F. Brown, M S Phillips, V Young, V C BlokAbstract:This report describes a novel diagnostic method for virus-vector trichodorid nematodes and associated Tobacco rattle virus (TRV) based on a real-time fluorogenic 5' nuclease PCR assay (TaqMan). Two independent primer/probe sets were designed targeting the 18S gene of the ribosomal cistron for the trichodorid species, Paratrichodorus pachydermus and Trichodorus similis. Assays using purified plasmid DNA containing clones of the 18S region and genomic DNA extracted from individuals from both nematode species displayed high specificity as no cros s-reaction was observed between the species or with two non-target trichodorid species Paratrichodorus anemones and Trichodorus primitivus. Relative quantification of target DNA present in unknown samples was performed by comparison of the fluorescence signals of the samples to those obtained from plasmid standard dilutions. Three primer/probe sets were also used to target TRV; one set for RNA1 and the two other sets for RNA2 of specific isolates (TRV-PpK20 and TRV-TpO1). Detection of both trichodorid species and TRV RNA1 and RNA2 from a single sample was achieved and field samples were used to demonstrate the potential of this assay to provide rapid, accurate and sensitive molecular information in relation to risk assessment in the field.
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First Report of the Stubby-Root Nematode, Paratrichodorus teres, from Potato in the Columbia Basin of Washington State.
Plant disease, 2005Co-Authors: Ekaterini Riga, R. NeilsonAbstract:Stubby-root nematodes of the genus Paratrichodorus are migratory ectoparasites that cause stunted and deformed roots. They also transmit Tobacco rattle virus, the causal agent of corky ringspot disease in potato. Thus, they are important to the potato industry in the Pacific Northwest, including the Columbia Basin of Washington state, which is one of the largest potato-producing regions in the United States. Stubby-root nematode species are difficult to identify because the morphological differences between the species are very small (4). Paratrichodorus teres is a morphologically similar species and has been reported mainly from temperate regions within Europe. P. teres has also been reported in potato fields in eastern Oregon (3). The morphological similarity between P. allius and P. teres creates problems for routine identification because trichodorid species have a conservative morphology and are separated by the following primary characteristics: females, type of genital system and vulva position; ma...
Eirini Karanastasi - One of the best experts on this subject based on the ideXlab platform.
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Molecular identification of two stubby root nematode species
American Journal of Potato Research, 2007Co-Authors: Ekaterini Riga, Eirini Karanastasi, C. Marcelo, G. Oliveira, R. NeilsonAbstract:Los nematodos que causan la raíz tocón son de creciente importancia para la industria papera en el Pacífico Noroeste (PNW) de EUA porque transmiten el Tobacco rattle virus (TRV), agente causal del anillo corchoso. En el PNW, el Paratrichodorus allius es el más importante vector del TRV en las áreas de cultivo de papa. También está presente en ciertas partes del PNW P. teres , una especie relacionada. P. allius y P. teres son morfológicamente similares, por lo que crean problemas para una identificación de rutina. Algunos estudios han utilizado técnicas moleculares para identificar las especies pertenecientes a los Trichodoridae. Los iniciadores de PCR en reversa, específicos para ambas especies de Paratrichodorus han sido diseñados y localizados en la región ITS-1 rADN y usados en combinación de un iniciador en la región 18S rADN. La confiabilidad del iniciador fue confirmada en un tamizado in vitro de diferentes poblaciones de P. allius y en análisis in silico de P. teres , sobre las respectivas especies objetivo. Más aún, la especificidad fue demostrada por ausencia de reacciones cruzadas con una gama de especies de nematodos parásitos de plantas típicas de las áreas de cultivo de papa en el PNW. Ha sido desarrollada una prueba de PCR doble que fue más efectiva para la detección de simultánea de ambas especies de Paratrichodorus . Stubby root nematodes are of increasing importance to the potato industry in the Pacific Northwest (PNW) of the USA as they transmit Tobacco rattle virus (TRY), the causal agent of corky ringspot disease. In the PNW, Paratrichodorus allius is the most prevalent TRV vector nematode species in potato growing areas. A closely related species, P. teres , is also found in parts of the PNW. P. allius and P. teres are morphologically similar, thus creating problems for routine identification. Few studies have utilized molecular techniques to identify species belonging to the Trichodoridae. Species-specific reverse PCR primers for both Paratrichodorus species were designed and located in the ITS-1 rDNA region and used in combination with a universal nematode forward primer located in the 18S rDNA. Primer reliability was confirmed by in vitro screening of different P. allius populations and in silico analysis of P. teres on the respective target species. Furthermore, specificity was demonstrated by the absence of cross-reactions with a range of common plant-parasitic nematode species typical of potato growing areas in the PNW. A duplex PCR test was developed that was effective for simultaneous detection of both target Paratrichodorus species.
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The ultrastructure of the feeding apparatus and pharyngeal tract of four European species of Trichodoridae (Nematoda: Triplonchida)
Nematology, 2004Co-Authors: Eirini Karanastasi, Wilfrida Decraemer, Urs Wyss, Derek J. F. BrownAbstract:Virus-vector plant-parasitic Paratrichodorus and Trichodorus nematodes acquire Tobravirus particles whilst ingesting root cell sap from virus-infected plants and these particles are specifically retained by being adsorbed on to the cuticle lining the wall of the nematode pharyngeal lumen. The feeding apparatus and pharyngeal ultrastructure of four trichodorid virus-vector species were examined to identify the occurrence of any structural characters that could account for particle retention at specific sites in this region. Similarities between Paratrichodorus and Trichodorus species are reported for the first time and new evidence is provided on the position of all gland sinuses and outlets. The occurrence of an inner spear in adult specimens is discussed.
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Interspecific differences in the fine structure of the body cuticle of Trichodoridae Thorne, 1935 (Nematoda: Diphtherophorina) and review of anchoring structures of the epidermis
Nematology, 2001Co-Authors: Eirini Karanastasi, Wilfrida Decraemer, M. T. M. Almeida, Jingwu Zheng, Derek J. F. BrownAbstract:Examination of the fine structure of the body cuticle of Trichodorus cylindricus , T. nanjingensis, T. pakistanensis , T. primitivus, Paratrichodorus anemones , P.hispanus , P.minor , P.pachydermus , P.porosus and P.teres revealed three distinct types, each characterised by differences in layers 4 to 6. A new description is provided for layer 5 and the presence of intracuticular canals and hemidesmosomes as types of anchoring structures for the epidermis are discussed.
W. Decraemer - One of the best experts on this subject based on the ideXlab platform.
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First report of stubby root nematode, Paratrichodorus teres (Nematoda: Trichodoridae) from Iran
Australasian Plant Disease Notes, 2014Co-Authors: R. Heydari, Z. Tanha Maafi, F. Omati, W. DecraemerAbstract:During a survey of plant-parasitic nematodes in fruit tree nurseries in Iran, a species of the genus Paratrichodorus from the family Trichodoridae was found in the rhizosphere of apricot seedlings in Shahrood, central Iran, then subsequently in Karaj orchards. Morphological and morphometric characters of the specimens were in agreement with P. teres . The D2/D3 expansion fragment of the large subunit (LSU) of rRNA gene of the nematode was also sequenced. P. teres is considered an economically important species in agricultural crop, worldwide. This is the first report of the occurrence of P. teres in Iran.
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Keys to the trichodorid species
Developments in Plant Pathology, 1995Co-Authors: W. DecraemerAbstract:Separate keys to species are provided for males and females for the genera Trichodorus and Paratrichodorus. The most important diagnostic features used in the keys are presented in Figs 5.1 – 5.5. For figures of the respective species see chapter on taxonomy. Species with a 50% variability of a diagnostic feature are indicated with an asterisk and occur twice in the key; rare variability of the characters used are not included in the key. A coputerized polytomous key will be published separately in cooperation with Dr. P. Baujard.
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Trichodorid nematodes from Australia with description of two new species from native vegetation
Australasian Plant Pathology, 1991Co-Authors: W. Decraemer, F. ReayAbstract:During a survey of plant parasitic nematodes associated with native vegetation in Australia, two new species of Paratrichodorus were found. Paratrichodorus orrae n.sp. was collected from Eucalyptus woodland and P. queenslandensis n.sp, from tropical rainforest, both closely resembling P. grandis. Paratrichodorus lobatus and the closely related P . teres are studied and the six trichodorid species recorded in Australia are listed.
