Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Walter de Gruyter GmbH  

Abstract

Viviparity is a very rare reproductive mode in nematodes, having been documented in only six species. Five of these species have been isolated among the dung beetles Onthophagus, suggesting that studying the environments associated with dung beetles may help shed light on why viviparity evolved in these particular species. Onthophagus atripennis is often closely associated with the viviparous nematode Tokorhabditis atripennis, as well as some other oviparous nematodes. Hence, the system involving T. atripennis and dung beetles could provide valuable insights into the adaptive significance of viviparity in nematodes. To explore this idea, it is essential to first gain a better understanding of the natural habitats of T. atripennis, which remain poorly understood. Therefore, we investigated the nematode communities associated with O. atripennis and identified potential habitats for T. atripennis in environments used by dung beetles. Nematodes associated with O. atripennis and those inhabiting its rearing cases were isolated from samples. Two Tokorhabditis species were isolated from the rearing cases of O. atripennis, suggesting that they inhabit environments used by O. atripennis. Regarding other oviparous nematodes, some appeared to have relatively strong associations with dung beetles, but more detailed studies are needed to confirm their specific habitats. Although further investigations are necessary, the fact that nematodes, including viviparous species, were isolated from environments used by dung beetles provides important information about the potential competitors or predators of T. atripennis in such environments.

DOI： 10.2478/jofnem-2025-0035

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Authorship：Corresponding author  

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Functional gene analysis tools in Caenorhabditis elegans are often ineffective in other nematodes due to differences in gonadal morphology and transgene silencing. Here, we established a method to generate stable transgenic lines in the nematodes Auanema freiburgense and Tokorhabditis tufae using microparticle bombardment coupled with hygromycin B selection. Despite using non-codon-optimized GFP, transgenic strains expressing fluorescent markers were obtained in both species. Additionally, an Auanema codon-optimized RFP construct showed robust expression in all tissues. This method will be valuable for future studies into the unusual sex determination, viviparity, and stress resistance in Auanema and Tokorhabditis .

DOI： 10.17912/micropub.biology.001585

PubMed

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Nematological Society  

DOI： 10.3725/jjn.54.1

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Brill  

Summary

The Mermithidae are primarily simple parasitoids of insects. In this study, we report the first observation of hyperparasitism by mermithid nematodes. Two Mermithidae individuals emerged from a specimen of the parasitoid wasp Coleocentrus incertus collected in Hokkaido, Japan. Although the nematodes were in the juvenile stage and many morphological characteristics were underdeveloped, we were able to observe cross fibre layers on the cuticles. A molecular sequence analysis of the 18S ribosomal DNA suggested that the nematode belonged to the genus Hexamermis, which was supported by the presence of the cross fibre layers. The phylogenetic analysis also suggested a close relationship between our specimens and ‘Mermithidae sp. NM1’, a taxon found in bumblebees, as differences between the sequences of the two taxa were minimal; however, further research is required to confirm the species’ identity. Hyperparasitism by nematodes is rare and is typically unsuccessful in non-host species, yet the nematodes in this study successfully parasitised a parasitoid wasp. Our study is the first to demonstrate that mermithid nematodes can exhibit hyperparasitism in addition to their known parasitic behaviour. The parasitic strategies of Mermithidae nematodes appear to be more flexible than previously assumed, indicating a high degree of adaptability as parasites.

DOI： 10.1163/15685411-bja10370

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Other Link： https://brill.com/downloadpdf/journals/nemy/aop/article-10.1163-15685411-bja10370/article-10.1163-15685411-bja10370.xml

Publishing type：Research paper (scientific journal)   Publisher：Walter de Gruyter GmbH  

Abstract

Viviparity is generally considered to be rare in animals. In nematodes, only six species of Rhabditida are viviparous. Five of these species have been identified in association with Onthophagus dung beetles, with Tokorhabditis atripennis being repeatedly isolated from the dung beetle Onthophagus atripennis in Japan. T. atripennis is easy to culture in a laboratory setting, and its host, O. atripennis, is distributed all over Japan. Therefore, T. atripennis is an ideal candidate for ecological and evolutionary studies on viviparity. However, the extent of their distribution and relationship with dung beetles, as well as habitats, remain unclear. In the present study, we conducted field surveys and successfully isolated 27 strains of viviparous nematodes associated with tunneler dung beetles from various regions of Japan, all of which were identified as T. atripennis. T. atripennis exhibited a strong association with Onthophagus dung beetles, especially O. apicetinctus and O. atripennis. And it was predominantly found in specific anatomical locations on the beetle bodies, such as the ‘groove between pronotum and elytron’ and the ‘back of the wings’. Our findings suggest that Onthophagus species are the primary hosts for T. atripennis, and T. atripennis exhibits a close relationship with the living environments of tunneler beetles. This association may play a significant role in the evolution of viviparity in nematodes.

DOI： 10.2478/jofnem-2024-0013

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Publishing type：Research paper (scientific journal)   Publisher：Brill  

Summary

Adult female entomoparasitic nematodes of the order Tylenchida have degenerate digestive organs and body surfaces that lack cuticles and are covered with microvilli. These morphologic features indicate that tylenchids absorb nutrients via the integument. A previous study hypothesised that the nutrient intake of entomoparasitic tylenchids evolved from oral to transdermal in a step-by-step manner, and this evolutionary process is reflected in the development of the integument ultrastructure of these species. However, the evolution of the nutrient absorption of entomoparasitic tylenchids remains unclear. This evolution has not been phylogenetically examined because of a lack of information on the integument structure associated with phylogenetic relationships. In the present study, we examined the integument ultrastructure and molecular sequence of four entomoparasitic tylenchids: Bradynema sp., Contortylenchus sp., C. genitalicola and Deladenus sp. The body surface of Bradynema sp. was covered with microvilli, suggesting that Bradynema sp. absorbs nutrients via the integument. By contrast, the body surfaces of Contortylenchus sp., C. genitalicola and Deladenus sp. were covered with a thin cuticle-like layer and well-developed epidermis without microvilli, suggesting that these species absorb nutrients only partially via the integument. We also classified the nutrient absorption mode based on the integument ultrastructure and molecular phylogenetic analysis of entomoparasitic tylenchids in previous studies. Our maximum parsimony analysis supported the step-by-step evolution hypothesised in the previous study. However, the parsimony analysis also generated new evolutionary processes in which atavism and/or saltation occur instead of stepwise evolution.

DOI： 10.1163/15685411-bja10323

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Other Link： https://brill.com/downloadpdf/journals/nemy/26/5/article-p565_6.xml

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Brill  

Summary

The pine wood nematode, Bursaphelenchus xylophilus, is the cause of pine wilt disease and reproduces by copulation within host pine trees. Female mate selection in B. xylophilus mating behaviour has been reported but definitive evidence is lacking. Furthermore, while the mating behaviour of the free-living nematode Caenorhabditis elegans on agar has been well understood, the mating behaviour of B. xylophilus on agar has not been studied in detail, and the differences in their characteristics remain unclear. Here, we addressed these knowledge gaps by observing B. xylophilus mating behaviour on agar. We identified six primary mating sub-behaviours in B. xylophilus males. Comparative analysis with C. elegans revealed distinct differences in the sequence of mating stages. Notably, B. xylophilus males actively searched for the female’s vulva during the wrapping stage, whereas females exhibited back-and-forth locomotion to align the male spicule with the vulva location. Additionally, we conducted mating assays using anaesthetised female nematodes to evaluate the female’s role in the mating behaviours of B. xylophilus. The mating duration increased significantly when females were anaesthetised, and the probabilities of reaching the wrapping and vulva location stages were reduced. Therefore, B. xylophilus females actively cooperate in mating behaviours. Our findings highlight unique aspects of mating behaviours in B. xylophilus and provide insights concerning differences in mating behaviours between B. xylophilus and C. elegans.

DOI： 10.1163/15685411-bja10310

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Other Link： https://brill.com/downloadpdf/journals/nemy/26/3/article-p309_6.xml

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

For insect-borne pathogens, phoretic ability is important not only to spread more widely and efficiently but also to evolve virulence. Bursaphelenchus xylophilus, the causal agent of pine wilt disease, is transmitted by the cerambycid beetle Monochamus alternatus, which is associated with pine tree host. Their specific phoretic ability to appropriate vectors depending on their life cycle is critical for efficient transfer to the correct host and is expected to enhance virulence. We evaluated how B. xylophilus acquired a specific relationship with M. alternatus with a focus on Bursaphelenchus okinawaensis, a close relative of B. xylophilus that has evolved a relationship with a cerambycid beetle vector. Bursaphelenchus okinawaensis has a single dispersal stage (dauer) larva (third-stage dispersal [DIII] larva), whereas B. xylophilus has two distinct dispersal stages (DIII and fourth-stage dispersal [DIV] larva). Also, the dauer formation in B. okinawaensis is not completely dependent on its beetle vector, whereas DIV larvae of B. xylophilus are induced by volatile from the beetle vector. We investigated the induction conditions of dauer larvae in B. okinawaensis and compared to with B. xylophilus. The dauer percentages of B. okinawaensis significantly increased when the nematode population on the plate increased or when we propagated the nematodes with a crude extract of cultured nematodes, which likely contained dauer-inducing pheromones. In addition, dauer formation tended to be enhanced by the crude extract at high temperatures. Furthermore, when we propagated the nematodes with M. alternatus pupae until the beetles eclosed, B. okinawaensis significantly developed into dauer larvae. However, only 1.3% of dauer larvae were successfully transferred to M. alternatus, the rate lower than that of B. xylophilus. DIII and DIV of B. xylophilus were induced by increasing the nematode population and the presence of the beetle vector, respectively. These results suggest that B. okinawaensis has acquired specificity for the cerambycid beetle through dauer formation, which is efficiently induced in the presence of the beetle, and the DIV larval stage, exclusive to the xylophilus group, may be crucial for high transfer ability to the beetle vector.

DOI： 10.3389/fphys.2023.1209695

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Conspecific recognition is the ability to distinguish and respond to individuals of the same species. In nematodes, this behavior can mediate aggregation, feeding behavior, or mating. Here, we investigated whether and how the predatory nematode Seinura caverna recognizes and avoids conspecifics to prey on. In predation assays, S. caverna did not kill conspecifics, but killed nematodes of three heterospecific species. Interestingly, S. caverna did not kill Ektaphelenchoides spondylis nematodes. S. caverna did not eject its stylet when encountering conspecifics or E. spondylis. The characterization of the internal cuticle structure of 13 nematode species suggested that the cuticle may play a role in the preying decision, as E. spondylis and S. caverna exhibited similar, type III, cuticle layers. Chemical extracts from S. caverna further repelled conspecifics. We discuss the potential hierarchical use of physical and chemical cues in S. caverna predation behavior and provide insights into the evolutionary adaptations and behavior of this organism.

DOI： 10.1093/icb/icad105

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Viviparity, a reproductive form that supplies nutrients to the embryo during gestation, has repeatedly and independently occurred in multiple lineages of animals. During the convergent evolution of viviparity, various modifications of development, structure, and physiology emerged. A new species of nematode, Tokorhabditis tufae, was discovered in the alkaline, hypersaline, and arsenic-rich environment of Mono lake. Its reproductive form is viviparity because it is obligately live-bearing and the embryo increases in size during development. However, the magnitude of the increase in size and nutrient provisioning are unclear. We measured egg and embryo sizes at three developmental stages in T. tufae. Eggs and embryos of T. tufae at the threefold stage were respectively 2.6- and 3.6-fold larger than at the single-cell stage. We then obtained T. tufae embryos at the single-cell, lima bean, and threefold developmental stages and investigated the egg hatching frequency at three different concentrations of egg salt buffer. Removal of embryos from the uterus halted embryonic development at the single-cell and lima bean stages in T. tufae irrespective of the solution used for incubation, indicating the provision of nutrients within the uterus. Ultrastructural and permeability evaluation showed that the permeability barrier did not form during embryonic development, resulting in increased molecular permeability. This high permeability caused by the absence of the permeability barrier likely enables supply of nutrients from the mother. The structural and physiological modifications in T. tufae are like those in other viviparous animals. We conclude that T. tufae is a viviparous rather than an ovoviviparous nematode. T. tufae will facilitate investigation of the evolution of viviparity in animals.

DOI： 10.3389/fphys.2023.1197477

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

A diplogastrid nematode was isolated from a dung beetle, Onthophagus sp., collected from a rotten mushroom in Kyoto, Japan. The species is characterised by its cheilostomatal shape, separated into 12 narrow plates (rugae), deep stegostom, large ellipsoidal amphids, conical female tail and characteristic receptaculum seminis in the female. Based on its phylogenetic status and stomatal composition, the species is typologically similar to two other diplogastrid genera, Neodiplogaster and Mononchoides. The species can be distinguished from these two genera by the size and shape of the amphid (small pore in Neodiplogaster), female tail shape (long and filiform in Mononchoides) and presence of receptaculum seminis (absence in the two nominal genera), and is described as a monotypic member of a new genus, Onthodiplogaster japonica n. gen., n. sp. Observation of feeding behaviour suggested that O. japonica n. gen., n. sp. does not show clear stomatal dimorphism or polymorphism, which is found in its close relatives, but the species can feed on nematodes (predation), fungi and bacteria. This monomorphic omnivory possibly represents its habitat of dung and other rotten materials, where the environment is biologically divergent, and its condition changes rapidly.

DOI： 10.1038/s41598-023-33586-1

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Other Link： https://www.nature.com/articles/s41598-023-33586-1

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Brill  

Summary

The nematode cuticle is an important structure that provides protection from abiotic environmental stresses and natural enemies. The cuticle ultrastructure of a Myolaimus species (culture code NKZ384) isolated from Kyoto, Japan, was examined in relation to its avoidance of predation by an aphelenchoidid predator, Seinura caverna. The survivability of Myolaimus sp. co-cultured with the predator was examined and compared with those of four Poikilolaimus spp. previously reported by the present authors. Myolaimus and two of the four Poikilolaimus spp. share a ‘baggy’ cuticle and resisted predation effectively. However, the ultrastructure differed between these two genera: i.e., the cuticle of Myolaimus sp. is seven-zoned, while that of P. regenfussi and P. oxycercus is five-zoned. In addition, Myolaimus sp. does not possess the characteristic osmophilic zone reported in Poikilolaimus spp. Therefore, although the ultrastructure differs, the thick and baggy cuticle found in these two phylogenetically distant genera exhibits functional convergence to resist predation.

DOI： 10.1163/15685411-bja10196

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Other Link： https://brill.com/downloadpdf/journals/nemy/aop/article-10.1163-15685411-bja10196/article-10.1163-15685411-bja10196.xml

Publishing type：Research paper (scientific journal)   Publisher：Walter de Gruyter GmbH  

Abstract

Two new species of Tokorhabditis, T. tauri n. sp. and T. atripennis n. sp., which were isolated from multiple Onthophagus species in North America and from O. atripennis in Japan, respectively, are described. The new species are each diagnosed by characters of the male tail and genitalia, in addition to molecular barcode differences that were previously reported. The description of T. tauri n. sp. expands the suite of known nematode associates of O. taurus, promoting ecological studies using a beetle that is an experimental model for insect–nematode–microbiota interactions in a semi-natural setting. Furthermore, our description of a third Tokorhabditis species, T. atripennis n. sp., sets up a comparative model for such ecological interactions, as well as other phenomena as previously described for T. tufae, including maternal care through obligate vivipary, the evolution of reproductive mode, and extremophilic living.

DOI： 10.2478/jofnem-2022-0028

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Pesticide Science Society of Japan  

DOI： 10.1584/jpestics.w22-19

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Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

DOI： 10.3389/fpls.2022.993482

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Sex determination mechanisms evolve surprisingly rapidly, yet little is known in the large nematode phylum other than for Caenorhabditis elegans, which relies on chromosomal XX-XO sex determination and a dosage compensation mechanism. Here we analyze by sex-specific genome sequencing and genetic analysis sex determination in two fungal feeding/plant-parasitic Bursaphelenchus nematodes and find that their sex differentiation is more likely triggered by random, epigenetic regulation than by more well-known mechanisms of chromosomal or environmental sex determination. There is no detectable difference in male and female chromosomes, nor any linkage to sexual phenotype. Moreover, the protein sets of these nematodes lack genes involved in X chromosome dosage counting or compensation. By contrast, our genetic screen for sex differentiation mutants identifies a Bursaphelenchus ortholog of tra-1, the major output of the C. elegans sex determination cascade. Nematode sex determination pathways might have evolved by "bottom-up" accretion from the most downstream regulator, tra-1.

DOI： 10.1038/s41467-022-30173-2

PubMed

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)  

DOI： 10.1163/15685411-bja10157

Scopus

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Pine wilt disease (PWD), which is caused by the pine wood nematode Bursaphelenchus xylophilus, is among the most serious tree diseases worldwide. PWD is thought to be initiated by sequential excessive hypersensitive responses to B. xylophilus. Previous studies have reported candidate pathogenic molecules inducing hypersensitive responses in pine trees susceptible to B. xylophilus. The functions of some of these molecules have been analyzed in model plants using transient overexpression; however, whether they can induce hypersensitive responses in natural host pines remains unclear due to the lack of a suitable functional analysis method. In this study, we established a novel functional analysis method for susceptible black pine (Pinus thunbergii) seed embryos using transient overexpression by the Apple latent spherical virus vector and investigated five secreted proteins of B. xylophilus causing cell death in tobacco to determine whether they induce hypersensitive responses in pine. We found that three of five molecules induced significantly higher expression in pathogenesis-related genes ( p < 0.05), indicating hypersensitive response in pine seed embryos compared with mock and green fluorescence protein controls. This result suggests that tobacco-based screening may detect false positives. This study is the first to analyze the function of pathogenic candidate molecules of B. xylophilus in natural host pines using exogenous gene expression, which is anticipated to be a powerful tool for investigating the PWD mechanism.

DOI： 10.3389/fpls.2022.872076

PubMed

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Pine wilt disease, caused by the pinewood nematode, <italic>Bursaphelenchus xylophilus</italic>, is one of the world’s most serious tree diseases. Although the <italic>B</italic>. <italic>xylophilus</italic> whole-genome sequence and comprehensive secretome profile have been determined over the past decade, it remains unclear what molecules are critical in pine wilt disease and govern <italic>B. xylophilus</italic> virulence in host pine trees. Here, a comparative secretome analysis among four isolates of <italic>B. xylophilus</italic> with distinct virulence levels was performed to identify virulence determinants. The four candidate virulence determinants of <italic>B. xylophilus</italic> highly secreted in virulent isolates included lipase (Bx-lip1), glycoside hydrolase family 30 (Bx-GH30), and two C1A family cysteine peptidases (Bx-CAT1 and Bx-CAT2). To validate the quantitative differences in the four potential virulence determinants among virulence groups at the protein level, we used real-time reverse-transcription polymerase chain reaction analysis to investigate these determinants at the transcript level at three time points: pre-inoculation, 3 days after inoculation (dai), and 7 dai into pine seedlings. The transcript levels of <italic>Bx-CAT1</italic>, <italic>Bx-CAT2</italic>, and <italic>Bx-GH30</italic> were significantly higher in virulent isolates than in avirulent isolates at pre-inoculation and 3 dai. A subsequent leaf-disk assay based on transient overexpression in <italic>Nicotiana benthamiana</italic> revealed that the GH30 candidate virulent factor caused cell death in the plant. Furthermore, we demonstrated that Bx-CAT2 was involved in nutrient uptake for fungal feeding via soaking-mediated RNA interference. These findings indicate that the secreted proteins Bx-GH30 and Bx-CAT2 contribute to <italic>B. xylophilus</italic> virulence in host pine trees and may be involved in pine wilt disease.

DOI： 10.3389/fpls.2021.640459

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Authorship：Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)  

DOI： 10.1163/15685411-bja10107

Scopus

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Authorship：Corresponding author   Language：English  

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

DOI： 10.1371/journal.pone.0241613

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s13355-020-00705-7

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Other Link： http://link.springer.com/article/10.1007/s13355-020-00705-7/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1128/MRA.01000-20

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Phenotypic plasticity is one of the most important strategies used by organisms with low mobility to survive in fluctuating environments. Phenotypic plasticity plays a vital role in nematodes because they have small bodies and lack wings or legs and thus, cannot move far by themselves. Bursaphelenchus xylophilus, the pathogenic nematode species that causes pine wilt disease, experiences fluctuating conditions throughout their life history; i.e., in both the phytophagous and mycetophagous phases. However, whether the functional morphology changes between the life phases of B. xylophilus remains unknown. Our study revealed differences in the ultrastructure of B. xylophilus between the two phases. Well-developed lateral alae and atrophied intestinal microvilli were observed in the phytophagous phase compared with the mycetophagous phase. The ultrastructure in the phytophagous phase was morphologically similar to that at the dauer stage, which enables the larvae to survive in harsh environments. It suggests that the living tree represents a harsh environment for B. xylophilus, and ultrastructural phenotypic plasticity is a key strategy for B. xylophilus to survive in a living tree. In addition, ultrastructural observations of obligate plant-parasitic species closely related to B. xylophilus revealed that B. xylophilus may be in the process of adapting to feed on plant cells.

DOI： 10.1038/s41598-020-68503-3

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Other Link： http://www.nature.com/articles/s41598-020-68503-3

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Extremophiles have much to reveal about the biology of resilience, yet their study is limited by sampling and culturing difficulties [1-3]. The broad success and small size of nematodes make them advantageous for tackling these problems [4-6]. We investigated the arsenic-rich, alkaline, and hypersaline Mono Lake (CA, US) [7-9] for extremophile nematodes. Though Mono Lake has previously been described to contain only two animal species (brine shrimp and alkali flies) in its water and sediments [10], we report the discovery of eight nematode species from the lake, including microbe grazers, parasites, and predators. Thus, nematodes are the dominant animals of Mono Lake in species richness. Phylogenetic analysis suggests that the nematodes originated from multiple colonization events, which is striking, given the young history of extreme conditions at Mono Lake [7, 11]. One species, Auanema sp., is new, culturable, and survives 500 times the human lethal dose of arsenic. Comparisons to two non-extremophile sister species [12] reveal that arsenic resistance is a common feature of the genus and a preadaptive trait that likely allowed Auanema to inhabit Mono Lake. This preadaptation may be partly explained by a variant in the gene dbt-1 shared with some Caenorhabditis elegans natural populations and known to confer arsenic resistance [13]. Our findings expand Mono Lake's ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance. The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles.

DOI： 10.1016/j.cub.2019.08.024

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DOI： 10.1038/s41598-018-28653-x

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Other Link： http://www.nature.com/articles/s41598-018-28653-x

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DOI： 10.1515/ap-2016-0034

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DOI： 10.1371/journal.pone.0123839

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DOI： 10.1534/g3.114.012385

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DOI： 10.1016/j.jbiosc.2013.01.003

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DOI： 10.1371/journal.pone.0067377

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DOI： 10.1007/s13355-012-0124-8

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.123.0.E11.0

CiNii Research

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1094/PHYTO.04.10.0109

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.121.0.164.0

CiNii Research

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1163/156854109X447006

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DOI： 10.1163/156854108X399164

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DOI： 10.1303/aez.2008.427

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DOI： 10.1016/j.jip.2008.01.009

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DOI： 10.1303/aez.2008.227

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DOI： 10.1016/j.jip.2007.11.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Nematological Society  

<I>Verticillium lecanii</I> is a potentially useful biological control agent (BCA) for soybean cyst nematode (SCN), <I>Heterodera glycines</I>. The objective of this study was to screen hybrid strains of <I>V. lecanii</I>, derived from protoplast fusion, for effective control agents of SCN, and to investigate whether the protoplast fusion technique is an effective tool for development of nematode control agents. Three parental strains (Vertalec&reg;, Mycotal&reg;, and B-2) and their 162 hybrid strains were screened in greenhouse pot tests. Some of these hybrid strains suppressed damage on soybean plants and reduced the density of SCN in the soil. In particular, one hybrid strain, AaF42, was observed to reduce the nematode egg density by 93.2% as compared with the control. Furthermore, this strain significantly reduced the cyst and egg density as compared with the parental strains. In conclusion, some of the hybrid strains exhibited enhanced biocontrol efficacy by protoplast fusion. Therefore, the protoplast fusion technique may be a potentially valuable tool for developing nematode-antagonistic fungi as BCA.

DOI： 10.3725/jjn.38.9

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DOI： 10.1303/jjaez.2007.205

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DOI： 10.1303/jjaez.2007.234

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DOI： 10.11519/jfsc.124.0.313.0

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J-GLOBAL

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Language：Japanese  

DOI： 10.11519/jfsc.122.0.256.0

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J-GLOBAL

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Language：English  

DOI： 10.1094/PHYTO-04-10-0109

Scopus

PubMed

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Language：Japanese   Publisher：全国森林病虫獣害防除協会  

CiNii Research

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Language：English  

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Language：English  

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J-GLOBAL

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Language：Japanese   Publisher：全国森林病虫獣害防除協会  

CiNii Research

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Language：Japanese   Publisher：日本応用動物昆虫学会  

CiNii Research

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Language：Japanese   Publisher：日本応用動物昆虫学会  

CiNii Research

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Event date： 2025.9

Presentation type：Oral presentation (general)  

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Event date： 2025.9

Presentation type：Poster presentation  

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Event date： 2025.9

Presentation type：Oral presentation (general)  

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Event date： 2025.9

Presentation type：Poster presentation  

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Event date： 2025.9

Presentation type：Poster presentation  

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Event date： 2025.9

Presentation type：Oral presentation (general)  

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Event date： 2025.8

Presentation type：Poster presentation  

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Event date： 2025.8

Presentation type：Oral presentation (general)  

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Event date： 2025.8

Presentation type：Oral presentation (general)  

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Event date： 2025.8

Presentation type：Poster presentation  

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Event date： 2025.8

Presentation type：Poster presentation  

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Event date： 2025.8

Presentation type：Poster presentation  

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Event date： 2025.8

Presentation type：Oral presentation (general)  

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Event date： 2025.7

Language：English   Presentation type：Poster presentation  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Poster presentation  

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Presentation type：Poster presentation  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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