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fungal constricting-ring trap formation

traitmech:000677 · CLASS · PROPOSED

A morphological phenotype in which a fungus forms three-celled hyphal ring traps whose mature ring cells inflate inward to mechanically capture nematodes.

Trait evidence (3)

  • DOI:10.1038/s41467-023-43235-w
    The R3 cell fuses with the S2 and R1 cells to complete CR formation

    Chen et al. (2023), Results, Morphogenesis and development of CR; primary XML at https://www.ebi.ac.uk/europepmc/webservices/rest/PMC10651832/fullTextXML and actual Figure 1 inspected. CR means constricting ring; R1-R3 are ring cells and S1-S2 stalk cells. Wild-type Drechslerella dactyloides strain 29 (CGMCC3.20198) forms complete rings before becoming inflation-competent. Methods use water agar at 25 degrees C with Caenorhabditis elegans for induction, and nematodes or 55-degree-C water for inflation assays; a separate horse-serum protocol is also described. These are distinct assay conditions, not universal requirements. Figure 1 separates immature-ring escape from mature-ring capture. Neither formation alone nor a circular outline proves immediate capture competence.

  • DOI:10.3897/BDJ.10.e96642
    Both of them produce constricting rings to capture nematodes.

    Zhang et al. (2022; published 16 December), scientific abstract, New information; primary XML at https://www.ebi.ac.uk/europepmc/webservices/rest/PMC9836436/fullTextXML. The two taxa are Drechslerella daliensis and D. xiaguanensis. Methods, taxon descriptions and actual Figure 1e were inspected. Soil isolates were purified by single-spore transfers; trapping structures were induced on corn meal agar observation plates at 26 degrees C using Panagrellus redivivus. Descriptions distinguish three-celled constricting rings from adhesive trapping devices. Figure 1e shows an uninflated ring, not time-resolved inflation. The taxon-name validity caveat is retained in the example.

  • DOI:10.1016/j.devcel.2014.04.021
    Cytokinesis involves constriction of a contractile actomyosin ring.

    Stachowiak et al. (2014), scientific abstract retrieved from Europe PMC for PMID:24914559, and primary article https://pmc.ncbi.nlm.nih.gov/articles/PMC4137230/. Results explicitly use constricting-ring terminology for intracellular actomyosin rings in fission-yeast protoplasts. This is terminology-boundary evidence, not another positive nematode-trap observation. The trap qualifier excludes this unrelated cellular structure; no cytokinesis mechanism, protein grounding or canonical example is transferred.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1038/s41467-023-43235-w

Parent traits (1)

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

  • Drechslerella daliensis (nom. inval.) NCBITaxon:2743661 DOI:10.3897/BDJ.10.e96642 Source-named D. daliensis, holotype culture CGMCC3.20131, isolated from burned forest soil at Cangshan Mountain, Dali, Yunnan, China, collected 25 July 2017. The primary taxon treatment and Figure 1e directly document three-celled constricting rings. Morphology and ITS, TEF1-alpha and RPB2 analyses support the study's identification. Live NCBI https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=taxonomy&id=2743661 resolves rank species but retains the nomenclatural qualifier nom. inval.; this is not a claim that the fungal name is validly published. The example is restricted to the observed culture and induction conditions, not every isolate or successful field biocontrol.

Discussions and Knowledge Gaps (2)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Resolve a closer trap-morphology parent without conflating cell shape.

CURATION TODO RESOLVED constricting-ring-scope-and-parent · raised by codex · 2026-10-08

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Parent phenotype METPO:1000059 is broader than this multicellular differentiation phenotype. Ring shaped METPO:1000680 denotes individual cell geometry, not a three-cell trapping apparatus. Mycelial growth and hyphal anastomosis alone do not define this trap. Exclude adhesive non-constricting rings, adhesive nets and generic nematophagy; neither a taxonomic genus nor prey capture by any mechanism is an exact synonym. Formation includes morphologically complete immature rings, not only already inflated traps. Do not infer that every formed ring immediately inflates. No xrefs, synonyms, SSSOM mappings or organism-level disjointness are asserted; closer hierarchy remains open. Stachowiak et al. (2014), DOI:10.1016/j.devcel.2014.04.021, also use constricting-ring terminology for fission-yeast cytokinesis. The trap-qualified label explicitly excludes those intracellular actomyosin rings; they are not synonyms or phenotype evidence here.

Resolution: Added fungal nematode-trap formation traitmech:000718 as the direct broader phenotype. The existing child definition entails specialized hyphal trap differentiation. This resolves only the parent gap; the historical scope contrasts, unasserted mappings, examples and separate mechanism questions remain applicable. Formation does not guarantee immediate capture. The column cell-count question is separately OPEN. Preserve the historical phenotype axiom and add METPO:1063000 SubClassOf METPO:1067100 on upstream adoption.

Separate trap formation, inflation mechanism and nomenclatural validity.

KNOWLEDGE GAP OPEN constricting-ring-mechanism-and-taxonomy · raised by codex · 2026-10-08

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Chen et al. investigate membrane reservoirs and SNARE-dependent inflation, but a protein-resolved causal graph requires review of the remaining perturbation/complementation figures, supplements and taxon-paired accessions. No universal SNARE requirement is inferred from morphology; mechanism is deferred, not claimed absent. Native provenance of laboratory strain 29 has not been established here, so it remains qualified evidence rather than a natural canonical example. NCBI's nom. inval. qualifier for D. daliensis concerns nomenclature, not absence of the observed trap; retain it pending nomenclatural review.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added fungal constricting-ring formation with two primary DOI sources, source-checked snippets and a nomenclature-qualified natural-isolate example. Ignored-and-hidden main/worktree/open-PR checks support 000677 and v553 block 1063000-1063099. Separated formation from maturation, inflation and capture; existing records unchanged. Timestamp is observed UTC.

  2. · EVIDENCE_AND_SCOPE_CORRECTION · codex

    Addressed #1823: qualified the label with trap to distinguish intracellular cytokinetic rings in fungi. Added a directly checked primary boundary-source snippet and explicit exclusion; it is not a third positive trap study. Preserved the initial event, definition, identifier, natural example and reservation.

  3. · REFINE_FUNGAL_TRAP_PARENT · codex

    Refined traitmech:000677 below fungal nematode-trap formation traitmech:000718 and resolved its temporary parent discussion by definition-based inference. Preserved child identity, definition, evidence, examples, mechanism gaps and earlier history.

Recorded curation sessions

  • · codex
    • CREATE — Add fungal constricting-ring formation

      Added traitmech:000677 with two directly inspected DOI sources and verbatim snippets; natural soil-isolate CGMCC3.20131 is paired with live NCBITaxon:2743661 and its nom. inval. qualifier. Distinguishes immature-ring formation, maturation, inflation and capture. Reserved full METPO:1063000-1063099 block in v553 after ignored-and-hidden worktree and exact-head open-PR checks. Protein mechanism remains explicitly deferred; no existing trait was changed.

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  • · codex
    • EDIT — Qualify constricting-ring trap label after adversarial review

      Addressed #1823 by adding trap to the label and explicit exclusion of intracellular actomyosin rings. Added DOI:10.1016/j.devcel.2014.04.021 with a verified scientific-abstract snippet as terminology-boundary evidence, not a third positive trap study. Preserved the original CREATE record history/records/fungal_constricting_ring_formation/2026-10-08T085642Z-codex-ff4ed3.yaml and initial TraitRecord event; appended the correction. Definition, ID, natural example, parent and block reservation unchanged.

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  • · codex
    • EDIT — Refine fungal trap morphology parent

      Refined the direct parent to traitmech:000718 and resolved only the parent-gap discussion by definition-based inference; preserved child identity, definition, evidence, examples, other mechanism gaps and previous history.

    Read this curation session