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Natsumi Kanzaki - One of the best experts on this subject based on the ideXlab platform.
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feeding dimorphism in a mycophagous nematode Bursaphelenchus sinensis
Scientific Reports, 2019Co-Authors: Natsumi Kanzaki, Taisuke Ekino, Robin M GiblindavisAbstract:Phenotypic plasticity has been widely reported in animals and can drive investment in new biological characters that engender ecological adaptability. The nematode family Diplogastridae, especially Pristionchus pacificus with its dramatic stomatal (feeding) dimorphism, has become an important model system to analyze the evolutionary and developmental aspects of polyphenism. However, this plasticity has not been confirmed in other nematode groups. In the present study, we experimentally examined the feeding dimorphism of a fungal feeding free-living nematode, Bursaphelenchus sinensis. In a laboratory culturing experiment, the nematode expressed dimorphism, i.e., a small proportion of the population manifested as a predatory form. This form only occurred in females and was not clearly influenced by the presence of potential prey species. In addition, the ratio of the predatory form to the mycophagous form varied among different fungal food species grown in monoculture on different culture media. The predatory form of B. sinensis was typologically similar to the monomorphic (specialized) predators belonging to the same family. However, some essential morphological characters were slightly different from the specialized predators, and their behaviours were clearly disparate, suggesting that predation in B. sinensis is derived from a different phylogenetic origin than that of the specialized predators.
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a simple method for distinguishing Bursaphelenchus xylophilus b mucronatus mucronatus and b m kolymensis nematoda aphelenchoididae by polymerase chain reaction with specific primers designed based on cytochrome oxidase subunit i genes
Applied Entomology and Zoology, 2019Co-Authors: Koji Matsunaga, Natsumi Kanzaki, Mitsuteru Akiba, Katsumi TogashiAbstract:Based on DNA sequences of mitochondrial cytochrome oxidase subunit I (mtCOI) genes, three PCR forward primers specific for Bursaphelenchus mucronatus mucronatus, B. m. kolymensis, and B. xylophilus (Nematoda: Aphelenchoididae), and one common PCR reverse primer were developed to determine the interspecific hybrids in a population. PCR amplification with the new primer pairs was expected to produce DNA fragments of 286 bp, 117 bp and 479 bp for B. m. mucronatus, B. m. kolymensis, and B. xylophilus, respectively. Electrophoresis of PCR products with the new primer pairs distinguished the two B. mucronatus subspecies and B. xylophilus collected in Japan. It also exhibited a band-free image for Bursaphelenchus doui, B. niphades, B. sinensis, B. firmae, Bursaphelenchus sp. (NK230), and Aphelenchoides stammeri, whereas it exhibited one (ca. 100-bp DNA fragment) and two (ca. 100 and 500-bp DNA fragments) bands for B. poligraphi and B. yongensis, respectively. As PCR products with other primer pairs for nuclear ribosomal RNA (rRNA) gene distinguished B. mucronatus (210 bp DNA fragment), B. xylophilus (557 bp fragment), and the eight other nematode species (no amplification), primer pairs for mtCOI and rRNA genes can determine whether B. poligraphi resides in specified trees or in study pine stands. Thus, those primer pairs would be helpful to find out hybrids between B. mucronatus and B. xylophilus and to analyze the dynamics of hybrids and introgressants in hybrid-derived populations in field and laboratory.
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diversity and plant pathogenicity of Bursaphelenchus and related nematodes in relation to their vector bionomics
Current Forestry Reports, 2018Co-Authors: Natsumi Kanzaki, Robin M GiblindavisAbstract:The nematode genus Bursaphelenchus is a highly divergent group containing fungal feeders and obligate and facultative plant parasites. The genus is also known as the phoretic (and parasitic) associates of many groups of insects. Further, two major plant pathogens, B. xylophilus and B. cocophilus, are members of this genus, and several other species are suspected to be weak to moderate plant pathogens. Here, the diversity of vector insects and host/habitat/plant species interactions, as well as phylogenetic relationships, are summarized for Bursaphelenchus species. The hypothetical origins of plant pathogenicity for different species of Bursaphelenchus are then discussed in relation to the bionomics of their vector insects. Phylogenetic analyses suggest that the genus is separated into four clades, and the basal clade will be further separated into two new genera. Based on a literature survey, the phoretic host association patterns appear different among the other three true Bursaphelenchus clades, i.e., one clade is mostly associated with bark beetles that occupy relatively dry niches (under bark), whereas the other two clades are associated with various groups of insects inhabiting diverse niches in other relatively humid conditions. Plant pathogenicity for a few members is hypothetically derived from the nematodes’ tolerance to the static resistance of host plants, i.e., the nematode species vectored by the insects attacking or interfacing with live plant tissue were provided an opportunity and, in a few cases, possessed the means to manifest plant pathogenicity with serious consequences, i.e., B. xylophilus and B. cocophilus.
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diversity and plant pathogenicity of Bursaphelenchus and related nematodes in relation to their vector bionomics
Current Forestry Reports, 2018Co-Authors: Natsumi Kanzaki, Robin M GiblindavisAbstract:Purpose of Review The nematode genus Bursaphelenchus is a highly divergent group containing fungal feeders and obligate and facultative plant parasites. The genus is also known as the phoretic (and parasitic) associates of many groups of insects. Further, two major plant pathogens, B. xylophilus and B. cocophilus, are members of this genus, and several other species are suspected to be weak to moderate plant pathogens. Here, the diversity of vector insects and host/habitat/plant species interactions, as well as phylogenetic relationships, are summarized for Bursaphelenchus species. The hypothetical origins of plant pathogenicity for different species of Bursaphelenchus are then discussed in relation to the bionomics of their vector insects.
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transmission electron microscopic observation of body cuticle structures of phoretic and parasitic stages of parasitaphelenchinae nematodes
PLOS ONE, 2017Co-Authors: Toyoshi Yoshiga, Taisuke Ekino, Yuko Takeuchikaneko, Natsumi KanzakiAbstract:Using transmission electron microscopy, we examined the body cuticle ultrastructures of phoretic and parasitic stages of the parasitaphelenchid nematodes Bursaphelenchus xylophilus, B. conicaudatus, B. luxuriosae, B. rainulfi; an unidentified Bursaphelenchus species, and an unidentified Parasitaphelenchus species. Nematode body cuticles usually consist of three zones, a cortical zone, a median zone, and a basal zone. The phoretic stages of Bursaphelenchus spp., isolated from the tracheal systems of longhorn beetles or the elytra of bark beetles, have a thick and radially striated basal zone. In contrast, the parasitic stage of Parasitaphelenchus sp., isolated from bark beetle hemocoel, has no radial striations in the basal zone. This difference probably reflects the peculiar ecological characteristics of the phoretic stage. A well-developed basal radially striated zone, composed of very closely linked proteins, is the zone closest to the body wall muscle. Therefore, the striation is necessary for the phoretic species to be able to seek, enter, and depart from host/carrier insects, but is not essential for internal parasites in parasitaphelenchid nematodes. Phylogenetic relationships inferred from near-full-length small subunit ribosomal RNA sequences suggest that the cuticle structures of parasitic species have apomorphic characters, e.g., lack of striation in the basal zone, concurrent with the evolution of insect parasitism from a phoretic life history.
Taisei Kikuchi - One of the best experts on this subject based on the ideXlab platform.
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telomere to telomere genome assembly of Bursaphelenchus okinawaensis strain sh1
Microbiology Resource Announcements, 2020Co-Authors: Simo Sun, Ryoji Shinya, Mehmet Dayi, Akemi Yoshida, Paul W Sternberg, Taisei KikuchiAbstract:Bursaphelenchus okinawaensis is a self-fertilizing, hermaphroditic, fungus-feeding nematode used as a laboratory model for the genus Bursaphelenchus, which includes the important pathogen Bursaphelenchus xylophilus Here, we report the nearly complete genome sequence of B. okinawaensis The 70-Mbp assembly contained six scaffolds (>11 Mbp each) with telomere repeats on their ends, indicating complete chromosomes.
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distribution and evolution of glycoside hydrolase family 45 cellulases in nematodes and fungi
BMC Evolutionary Biology, 2014Co-Authors: Akina Hino, Yuuri Hirooka, Hiroshi Masuya, Isheng J Tsai, John T Jones, Juan E Palomaresrius, Natsumi Kanzaki, Taisei KikuchiAbstract:Background Horizontal gene transfer (HGT) has been suggested as the mechanism by which various plant parasitic nematode species have obtained genes important in parasitism. In particular, cellulase genes have been acquired by plant parasitic nematodes that allow them to digest plant cell walls. Unlike the typical glycoside hydrolase (GH) family 5 cellulase genes which are found in several nematode species from the order Tylenchida, members of the GH45 cellulase have only been identified in a cluster including the families Parasitaphelenchidae (with the pinewood nematode Bursaphelenchus xylophilus) and Aphelenchoididae, and their origins remain unknown.
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genomic insights into the origin of parasitism in the emerging plant pathogen Bursaphelenchus xylophilus
PLOS Pathogens, 2011Co-Authors: Taisei Kikuchi, Isheng J Tsai, Natsumi Kanzaki, Koichi Hasegawa, James Cotton, Jonathan J Dalzell, Paul Mcveigh, Takuma Takanashi, Samuel Assefa, Peter J A CockAbstract:Bursaphelenchus xylophilus is the nematode responsible for a devastating epidemic of pine wilt disease in Asia and Europe, and represents a recent, independent origin of plant parasitism in nematodes, ecologically and taxonomically distinct from other nematodes for which genomic data is available. As well as being an important pathogen, the B. xylophilus genome thus provides a unique opportunity to study the evolution and mechanism of plant parasitism. Here, we present a high-quality draft genome sequence from an inbred line of B. xylophilus, and use this to investigate the biological basis of its complex ecology which combines fungal feeding, plant parasitic and insect-associated stages. We focus particularly on putative parasitism genes as well as those linked to other key biological processes and demonstrate that B. xylophilus is well endowed with RNA interference effectors, peptidergic neurotransmitters (including the first description of ins genes in a parasite) stress response and developmental genes and has a contracted set of chemosensory receptors. B. xylophilus has the largest number of digestive proteases known for any nematode and displays expanded families of lysosome pathway genes, ABC transporters and cytochrome P450 pathway genes. This expansion in digestive and detoxification proteins may reflect the unusual diversity in foods it exploits and environments it encounters during its life cycle. In addition, B. xylophilus possesses a unique complement of plant cell wall modifying proteins acquired by horizontal gene transfer, underscoring the impact of this process on the evolution of plant parasitism by nematodes. Together with the lack of proteins homologous to effectors from other plant parasitic nematodes, this confirms the distinctive molecular basis of plant parasitism in the Bursaphelenchus lineage. The genome sequence of B. xylophilus adds to the diversity of genomic data for nematodes, and will be an important resource in understanding the biology of this unusual parasite.
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identification of putative expansin like genes from the pine wood nematode Bursaphelenchus xylophilus and evolution of the expansin gene family within the nematoda
Nematology, 2009Co-Authors: Taisei Kikuchi, Nurul Karim, Malcolm W Kennedy, Maurice Moens, John T JonesAbstract:We report the cloning and characterisation of genes encoding expansin-like proteins from the pine wood nematodes, Bursaphelenchus xylophilus and B. mucronatus. A small family of genes is present in both species and the Bursaphelenchus genes are most similar to expansins and expansin-like proteins from the potato cyst nematode Globodera rostochiensis and root-knot nematodes. Molecular modelling suggests that the genes could encode a protein with a structure similar to that of functionally characterised expansins. Expression analysis showed that the Bursaphelenchus expansin-like genes are expressed solely in the pharyngeal gland cells, implying a role in the host-parasite interaction, most likely in assisting migration through the plant. Some G. rostochiensis and root-knot nematode expansins are composed of a carbohydrate-binding domain coupled to an expansin domain but no carbohydrate binding domain is present on any of the Bursaphelenchus sequences. We suggest a model for evolution of the expansin gene family within the plant-parasitic nematodes of the Tylenchida and Aphelenchida.
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Bursaphelenchus xylophilus opportunities in comparative genomics and molecular host parasite interactions
Molecular Plant Pathology, 2008Co-Authors: John T Jones, Maurice Moens, M Mota, Taisei KikuchiAbstract:Most Bursaphelenchus species are fungal feeding nematodes that colonize dead or dying trees. However, Bursaphelenchus xylophilus, the pine wood nematode, is also a pathogen of trees and is the causal agent of pine wilt disease. B. xylophilus is native to North America and here it causes little damage to trees. Where it is introduced to new regions it causes huge damage. The most severely affected areas are found in the Far East but more recently B. xylophilus has been introduced into Portugal and the potential for damage here is also high. As incidence and severity of pine wilt disease are linked to temperature we suggest that climate change is likely to exacerbate the problems caused by B. xylophilus and, in addition, will extend (northwards in Europe) the range in which pine wilt disease can occur. Here we review what is currently known about the interactions of B. xylophilus with its hosts, including recent developments in our understanding of the molecular biology of pathogenicity in the nematode. We also examine the potential developments that could be made by more widespread use of genomics tools to understand interactions between B. xylophilus, bacterial pathogens that have been implicated in disease and host trees.
John T Jones - One of the best experts on this subject based on the ideXlab platform.
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distribution and evolution of glycoside hydrolase family 45 cellulases in nematodes and fungi
BMC Evolutionary Biology, 2014Co-Authors: Akina Hino, Yuuri Hirooka, Hiroshi Masuya, Isheng J Tsai, John T Jones, Juan E Palomaresrius, Natsumi Kanzaki, Taisei KikuchiAbstract:Background Horizontal gene transfer (HGT) has been suggested as the mechanism by which various plant parasitic nematode species have obtained genes important in parasitism. In particular, cellulase genes have been acquired by plant parasitic nematodes that allow them to digest plant cell walls. Unlike the typical glycoside hydrolase (GH) family 5 cellulase genes which are found in several nematode species from the order Tylenchida, members of the GH45 cellulase have only been identified in a cluster including the families Parasitaphelenchidae (with the pinewood nematode Bursaphelenchus xylophilus) and Aphelenchoididae, and their origins remain unknown.
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identification of putative expansin like genes from the pine wood nematode Bursaphelenchus xylophilus and evolution of the expansin gene family within the nematoda
Nematology, 2009Co-Authors: Taisei Kikuchi, Nurul Karim, Malcolm W Kennedy, Maurice Moens, John T JonesAbstract:We report the cloning and characterisation of genes encoding expansin-like proteins from the pine wood nematodes, Bursaphelenchus xylophilus and B. mucronatus. A small family of genes is present in both species and the Bursaphelenchus genes are most similar to expansins and expansin-like proteins from the potato cyst nematode Globodera rostochiensis and root-knot nematodes. Molecular modelling suggests that the genes could encode a protein with a structure similar to that of functionally characterised expansins. Expression analysis showed that the Bursaphelenchus expansin-like genes are expressed solely in the pharyngeal gland cells, implying a role in the host-parasite interaction, most likely in assisting migration through the plant. Some G. rostochiensis and root-knot nematode expansins are composed of a carbohydrate-binding domain coupled to an expansin domain but no carbohydrate binding domain is present on any of the Bursaphelenchus sequences. We suggest a model for evolution of the expansin gene family within the plant-parasitic nematodes of the Tylenchida and Aphelenchida.
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Bursaphelenchus xylophilus opportunities in comparative genomics and molecular host parasite interactions
Molecular Plant Pathology, 2008Co-Authors: John T Jones, Maurice Moens, M Mota, Taisei KikuchiAbstract:Most Bursaphelenchus species are fungal feeding nematodes that colonize dead or dying trees. However, Bursaphelenchus xylophilus, the pine wood nematode, is also a pathogen of trees and is the causal agent of pine wilt disease. B. xylophilus is native to North America and here it causes little damage to trees. Where it is introduced to new regions it causes huge damage. The most severely affected areas are found in the Far East but more recently B. xylophilus has been introduced into Portugal and the potential for damage here is also high. As incidence and severity of pine wilt disease are linked to temperature we suggest that climate change is likely to exacerbate the problems caused by B. xylophilus and, in addition, will extend (northwards in Europe) the range in which pine wilt disease can occur. Here we review what is currently known about the interactions of B. xylophilus with its hosts, including recent developments in our understanding of the molecular biology of pathogenicity in the nematode. We also examine the potential developments that could be made by more widespread use of genomics tools to understand interactions between B. xylophilus, bacterial pathogens that have been implicated in disease and host trees.
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expressed sequence tag est analysis of the pine wood nematode Bursaphelenchus xylophilus and b mucronatus
Molecular and Biochemical Parasitology, 2007Co-Authors: Taisei Kikuchi, Takuya Aikawa, Hajime Kosaka, Leighton Pritchard, Nobuo Ogura, John T JonesAbstract:Most Bursaphelenchus species feed on fungi that colonise dead or dying trees. However, Bursaphelenchus xylophilus is unique in that in addition to feeding on fungi it has the capacity to be a parasite of live pine trees. We present an analysis of over 13,000 expressed sequence tags (ESTs) from B. xylophilus and, by way of contrast, over 3000 ESTs from a closely related species that does not parasitise plants as readily; B. mucronatus. Four libraries from B. xylophilus, from a variety of life stages including fungal feeding nematodes, nematodes extracted from plants and dauer-like stage nematodes, and one library from B. mucronatus were constructed and used to generate ESTs. Contig analysis showed that the 13,327 B. xylophilus ESTs could be grouped into 2110 contigs and 4377 singletons giving a total of 6487 identified genes. Similarly the 3193 B. mucronatus ESTs yielded a total of 2219 identified genes from 425 contigs and 1794 singletons. A variety of proteins potentially important in the parasitic process of B. xylophilus and B. mucronatus, including plant and fungal cell wall degrading enzymes and a novel gene potentially encoding a expansin-like protein that may disrupt non-covalent bonds in the plant cell wall were identified in the libraries. Additionally several gene candidates potentially involved in dauer entry or maintenance were also identified in the EST dataset. The EST sequences from this study will provide a solid base for future research on the biology, pathogenicity and evolutionary history of this nematode group.
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a family of glycosyl hydrolase family 45 cellulases from the pine wood nematode Bursaphelenchus xylophilus
FEBS Letters, 2004Co-Authors: Taisei Kikuchi, Takuya Aikawa, John T Jones, Hajime Kosaka, Nobuo OguraAbstract:We have characterized a family of GHF45 cellulases from the pine wood nematode Bursaphelenchus xylophilus. The absence of such genes from other nematodes and their similarity to fungal genes suggests that they may have been acquired by horizontal gene transfer (HGT) from fungi. The cell wall degrading enzymes of other plant parasitic nematodes may have been acquired by HGT from bacteria. B. xylophilus is not directly related to other plant parasites and our data therefore suggest that horizontal transfer of cell wall degrading enzymes has played a key role in evolution of plant parasitism by nematodes on more than one occasion.
M Mota - One of the best experts on this subject based on the ideXlab platform.
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first detection of Bursaphelenchus xylophilus associated with pinus nigra in portugal and in europe
Forest Pathology, 2015Co-Authors: M L Inacio, Paulo Vieira, Edmundo Sousa, Filomena Nobrega, Luis Bonifacio, Pedro Naves, M MotaAbstract:Summary The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. This species has been reported from the United States of America and Asia associated with important forestry tree species, including pine, spruce, fir, larch and other conifers. However, in Europe, the devastating epidemics centred in Portugal's mainland, and the most recent detections in Madeira Island and in Spain were restricted to Pinus pinaster alone. During the 2013 national survey, wilted Pinus nigra trees, from the central region of Portugal, were sampled. A Bursaphelenchus species was found in very high numbers, with an average up to 5000 nematodes per 10 g of wood, collected from different pine trees. Morphological identification of those specimens, including the presence of a bursa in the male tail, four lateral incisures, shape of spicules, presence of a vulva flap and female rounded tail, was in agreement with the PWN description. Species identification was confirmed also using species-specific primers targeting the ITS region of the ribosomal DNA to the PWN. Herein, B. xylophilus is reported for the first time associated with declining P. nigra in Portugal, and in Europe. Simultaneously, the insect vector Monochamus galloprovincialis was also detected colonizing the PWN-infected P. nigra.
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pinewood nematode associated bacteria contribute to oxidative stress resistance of Bursaphelenchus xylophilus
BMC Microbiology, 2013Co-Authors: Cláudia S. L. Vicente, M Mota, Yoriko Ikuyo, Koichi HasegawaAbstract:Background Pine wilt disease (PWD) caused by the pinewood nematode Bursaphelenchus xylophilus is one of the most serious forest diseases in the world. The role of B. xylophilus-associated bacteria in PWD and their interaction with the nematode, have recently been under substantial investigation. Several studies report a potential contribution of the bacteria for the PWD development, either as a helper to enhance the pathogenicity of the nematode or as a pathogenic agent expressing interesting traits related to lifestyle host-adaptation.
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new insights into the phylogeny and worldwide dispersion of two closely related nematode species Bursaphelenchus xylophilus and Bursaphelenchus mucronatus
PLOS ONE, 2013Co-Authors: Filipe Pereira, M Mota, Luis Fonseca, Isabel Abrantes, Claudia Moreira, Barbara Van Asch, A AmorimAbstract:The pinewood nematode, Bursaphelenchus xylophilus, is one of the greatest threats to coniferous forests worldwide, causing severe ecological damage and economic loss. The biology of B. xylophilus is similar to that of its closest relative, B. mucronatus, as both species share food resources and insect vectors, and have very similar morphological characteristics, although little pathogenicity to conifers has been associated with B. mucronatus. Using both nuclear and mitochondrial DNA markers, we show that B. xylophilus and B. mucronatus form distinct phylogenetic groups with contrasting phylogeographic patterns. B. xylophilus presents lower levels of intraspecific diversity than B. mucronatus, as expected for a species that evolved relatively recently through geographical or reproductive isolation. Genetic diversity was particularly low in recently colonised areas, such as in southwestern Europe. By contrast, B. mucronatus displays high levels of genetic diversity and two well-differentiated clades in both mitochondrial and nuclear DNA phylogenies. The lack of correlation between genetic and geographic distances in B. mucronatus suggests intense gene flow among distant regions, a phenomenon that may have remained unnoticed due to the reduced pathogenicity of the species. Overall, our findings suggest that B. xylophilus and B. mucronatus have different demographic histories despite their morphological resemblance and ecological overlap. These results suggest that Bursaphelenchus species are a valuable model for understanding the dispersion of invasive species and the risks posed to native biodiversity and ecosystems.
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characterization of bacteria associated with pinewood nematode Bursaphelenchus xylophilus
PLOS ONE, 2012Co-Authors: Cláudia S. L. Vicente, Margarida Espada, M Mota, Pedro Barbosa, Francisco X Nascimento, Bernard R Glick, Solange OliveiraAbstract:Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD.
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the pinewood nematode Bursaphelenchus xylophilus in madeira island
Helminthologia, 2012Co-Authors: Luis Fonseca, M Mota, J M S Cardoso, A Lopes, M Pestana, F Abreu, N Nunes, Isabel AbrantesAbstract:The environmental conditions in Madeira Island are favorable for the presence and dissemination of the pinewood nematode (PWN), Bursaphelenchus xylophilus. Five hundred Pinus pinaster wood samples were collected in several forest areas and PWN was detected in 22.8 % of the samples. Bursaphelenchus xylophilus isolates from Madeira Island displayed the species-specific diagnostic characters. A morphological variation in the female tail terminus was detected. In most females, the tail presented a broadly rounded terminus and, occasionally, a digitate terminus with a terminal nipple-like extension resembling a mucro. PCR ITS-RFLP analysis revealed that Madeira Island isolates exhibited patterns specific to the species B. xylophilus and similar to virulent isolates. Amplified ITS regions were further sequenced and no genetic diversity was found for this genomic region among 17 Portuguese isolates (Madeira Island and Continental Portugal). Phylogenetic analysis revealed that Portuguese isolates grouped with isolates from China, Korea and one isolate from Japan.
Robin M. Giblin-davis - One of the best experts on this subject based on the ideXlab platform.
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Parasitaphelenchidae)
2016Co-Authors: Bursaphelenchus Xylophilus, Robin M. Giblin-davisAbstract: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 rapi
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New plant-parasitic nematode from the mostly mycophagous Genus Bursaphelenchus discovered inside figs
2016Co-Authors: Natsumi Kanzaki, Ryusei Tanaka, Robin M. Giblin-davis, Kerrie A. DaviesAbstract:A new nematode species, Bursaphelenchus sycophilus n. sp. is described. The species was found in syconia of a fig species, Ficus variegata during a field survey of fig-associated nematodes in Japan. Because it has a well-developed stylet and pharyngeal glands, the species is considered an obligate plant parasite, and is easily distinguished from all other fungal-feeding species in the genus based upon these characters. Although B. sycophilus n. sp. shares an important typological character, male spicule possessing a strongly recurved condylus, with the ‘‘B. eremus group’ ’ and the ‘‘B. leoni group’ ’ of the genus, it was inferred to be monophyletic with the ‘‘B. fungivorus group’’. The uniquely shaped stylet and well-developed pharyngeal glands is reminiscent of the fig-floret parasitic but paraphyletic assemblage of ‘‘Schistonchus’’. Thus, these morphological characters appear to be an extreme example of convergent evolution in the nematode family, Aphelenchoididae, inside figs. Other characters shared by the new species and its close relatives, i.e., lack of ventral P1 male genital papilla, female vulval flap, and papilla-shaped P4 genital papillae in males, corroborate the molecular phylogenetic inference. The unique biological character of obligate plant parasitism and highly derived appearance of the ingestive organs of Bursaphelenchus sycophilus n. sp. expands our knowledge of the potential morphological, physiologica
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New plant-parasitic nematode from the mostly mycophagous genus Bursaphelenchus discovered inside figs in Japan
PLoS ONE, 2014Co-Authors: Natsumi Kanzaki, Ryusei Tanaka, Robin M. Giblin-davis, Kerrie A. DaviesAbstract:A new nematode species, Bursaphelenchus sycophilus n. sp. is described. The species was found in syconia of a fig species, Ficus variegata during a field survey of fig-associated nematodes in Japan. Because it has a well-developed stylet and pharyngeal glands, the species is considered an obligate plant parasite, and is easily distinguished from all other fungal-feeding species in the genus based upon these characters. Although B. sycophilus n. sp. shares an important typological character, male spicule possessing a strongly recurved condylus, with the "B. eremus group" and the "B. leoni group" of the genus, it was inferred to be monophyletic with the "B. fungivorus group". The uniquely shaped stylet and well-developed pharyngeal glands is reminiscent of the fig-floret parasitic but paraphyletic assemblage of "Schistonchus". Thus, these morphological characters appear to be an extreme example of convergent evolution in the nematode family, Aphelenchoididae, inside figs. Other characters shared by the new species and its close relatives, i.e., lack of ventral P1 male genital papilla, female vulval flap, and papilla-shaped P4 genital papillae in males, corroborate the molecular phylogenetic inference. The unique biological character of obligate plant parasitism and highly derived appearance of the ingestive organs of Bursaphelenchus sycophilus n. sp. expands our knowledge of the potential morphological, physiological and developmental plasticity of the genus Bursaphelenchus.
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Molecular characterization and development of real-time PCR assay for pine-wood nematode Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae)
PLoS ONE, 2013Co-Authors: Weimin Ye, Robin M. Giblin-davisAbstract: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.
