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fungal nonconstricting-ring trap formation

traitmech:000680 · CLASS · PROPOSED

A morphological phenotype in which a fungus forms stalked, three-celled hyphal rings that trap nematodes without inward inflation of the ring cells.

Trait evidence (2)

  • DOI:10.1007/s102670200061
    A nonconstricting ring (arrow) is capturing a nematode (asterisk).

    Saikawa and Takahashi (2002), Figure 8 caption, page 418; all three pages and actual Figures 1-20 directly inspected at https://www.jstage.jst.go.jp/article/mycosci/43/5/43_MYC43417/_pdf. Time-lapse microscopy distinguishes noninflating three-cell rings in Dactylella leptospora and Dactylaria candida from the inflating Arthrobotrys dactyloides comparator. Figures 8-14 and 15-20 show the former taxa; Figures 1-7 show the comparator. Hook-tip fusion lacks the opposing bud seen in that comparator; stalk lengths vary. Adhesive ultrastructure is attributed to Saikawa (1985), not newly imaged here. These morphological observations do not identify causal proteins.

  • DOI:10.1016/j.mycres.2006.04.011
    D. varietas forms both adhesive knobs and non-constricting rings

    Li et al. (2006), scientific Abstract, directly retrieved as published abstract XML for PMID:16876699 at https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=16876699&retmode=xml. Abstract-only access: full Methods and figures were not retrieved. The independent description of Dactylellina sichuanensis and D. varietas from China reports capture with knobs and nonconstricting rings. The quoted clause contrasts D. varietas with nontrapping Dactylella oxyspora. Co-occurring trap types are not disjoint organism categories. The sequence analyses concern taxonomy, not a sequence-predicted trapping phenotype; no current taxonomic equivalence for those new taxa is asserted.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1007/s102670200061

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.

  • Dactylellina leptospora NCBITaxon:430499 DOI:10.1007/s102670200061 Source-named Dactylella leptospora, natural TGU orchard-soil isolate collected June 1998. Observed on water agar at 18-22 degrees C with Rhabditis sp.; Figures 8-14 document capture and ring development. Live NCBI https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=taxonomy&id=430499 resolves rank species, exact label Dactylellina leptospora and synonym Dactylella leptospora. This is not a strain accession or an assertion about every isolate, universal culture conditions or 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 nonconstricting-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.

Phenotype METPO:1000059 is a broad parent. Ring shaped METPO:1000680 concerns individual-cell geometry, not this multicellular trapping apparatus. Mycelial growth traitmech:000074 explicitly concerns bacteria; hyphal anastomosis traitmech:000605 concerns fusion. Distinguish nonconstricting traps from an immature constricting ring that has not yet acquired inflation competence, adhesive-net loops, unicellular knobs, columns and intracellular cytokinetic rings. A circular outline or nematophagous genus is not sufficient. No exact synonyms, xrefs, SSSOM equivalences or organism-level disjointness are asserted. Neighboring scope exclusions do not constitute unresolved groundings, and their closer-parent TODOs remain open.

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:1063300 SubClassOf METPO:1067100 on upstream adoption.

Separate ring morphogenesis from adhesion and infection mechanisms.

KNOWLEDGE GAP OPEN nonconstricting-ring-mechanism · 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.

The observed developmental sequence is not evidence that a particular protein is necessary or sufficient. Formation, adhesion, capture, penetration and digestion are separate endpoints; formation alone does not guarantee capture in every condition. A protein-resolved causal graph needs direct perturbation/complementation evidence and taxon-paired accessions. Do not transfer inflation mechanisms from constricting rings or adhesion proteins from knobs and nets. No universal stalk length, detachment, induction medium or prey requirement is asserted; mechanism is deferred, not claimed absent.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added fungal nonconstricting-ring trap formation with two primary DOI sources, contiguous source-checked snippets and a qualified natural-isolate example. Ignored-and-hidden main/worktree/open-PR checks support 000680 and v556 block 1063300-1063399. Separated morphology from molecular mechanism and species rank from strain identity. Existing records unchanged. Timestamp is observed UTC.

  2. · REFINE_FUNGAL_TRAP_PARENT · codex

    Refined traitmech:000680 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 evidence-backed fungal nonconstricting-ring trap formation

      Added traitmech:000680 as a PROPOSED morphology class with Saikawa and Takahashi 2002 DOI:10.1007/s102670200061 and Li et al. 2006 DOI:10.1016/j.mycres.2006.04.011. Directly read the three-page primary microscopy paper and all figures; the second study is explicitly abstract-only. Added contiguous caption and abstract snippets, qualified natural TGU isolate example NCBITaxon:430499 at species rank, and open scope/parent and mechanism discussions. Kept formation, noninflating capture and molecular mechanism separate. Writer defaults to dry-run, validates before writing and refuses changed parent/target/proposal preimages; 20 focused tests passed. Ignored-and-hidden main, all worktrees, CommunityMech and complete paginated open-PR checks support local ID000680, cohort v556 and full METPO1063300-1063399 block. Prior records untouched. METPO placeholder is not a released term.

    Read this curation session
  • · 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