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fungal arbuscule formation

traitmech:000664 · CLASS · PROPOSED

A morphological phenotype in which a fungus forms highly branched hyphal structures, called arbuscules, within living plant cells during arbuscular mycorrhizal symbiosis.

Trait evidence (2)

  • DOI:10.1104/pp.109.141879
    In the arbuscular mycorrhizal symbiosis, the fungal symbiont colonizes root cortical cells, where it establishes differentiated hyphae called arbuscules.

    Pumplin and Harrison (2009), PMID:19692536, PMC2754618; scientific-abstract sentence checked against Europe PMC and https://academic.oup.com/plphys/article/151/2/809/6108581. Main text, Figures 1-7 and supplementary Figures S1-S9 were inspected; Figure 7 is a model. The supplementary movie was not viewed. Glomus versiforme colonized transgenic Medicago truncatula A17 roots. Host fluorescent markers distinguish periarbuscular membrane domains; they are not fungal protein anchors or nutrient-flux measurements. The host-derived membrane separates fungal branches from host cytoplasm. Fungal isolate provenance was not established, so this experiment is not a natural canonical example.

  • DOI:10.3390/plants8060142
    All AMF strains formed arbuscules in the parenchyma cells of the mycothalli

    Kobae et al. (2019), PMID:31151150, PMC6631804; Results 2.2 clause. Primary text and Figures 1-4 on pages 1-11 of https://rakuno.repo.nii.ac.jp/record/6472/files/R-2020-321_kobae.pdf and all four supplementary pages were inspected. Liverwort Marchantia paleacea thallus observations support plant-cell, not root-only, scope. Methods 3.2 and Figure S1 identify cultures separately from unidentified field-root trapping. For DAOM197198, Results 2.2 reports arbuscules at 18 dps and none until 14 dps; S2A instead describes rhizoid-only hyphae at 18 dps and S2B arbuscules at 28 dps. Onset remains unresolved. Pigmentation alone is insufficient. Figure 4C shows root arbuscules, although Results points to 4B and uses dps instead of the caption's dpi. Figure 3 and Methods 3.6 disagree on phylogenetic method; no independent fungal species assignment from mixed rDNA is asserted.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.3390/plants8060142

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.

  • Entrophospora etunicata NCBITaxon:937382 DOI:10.3390/plants8060142 MAFF520053 (H1-1), reported as Claroideoglomus etunicatum in Methods 3.2 and actual Figure S1, forms arbuscules in Marchantia paleacea thallus cells. NARO's collection record https://www.gene.affrc.go.jp/databases-micro_search_detail_en.php?maff=520053 lists soybean-field soil, Tokyo, October 1987, H. Hirata; it was deposited as Glomus etunicatum. These separate fields support this culture's field-isolate origin, not a trait evidence snippet. NCBI Taxonomy resolves species 937382 to Entrophospora etunicata, with Claroideoglomus etunicatum as a homotypic synonym; name correspondence is not independent reidentification of the culture.

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 the phenotype parent and attributed haustorium umbrella.

CURATION TODO OPEN fungal-arbuscule-scope-and-hierarchy · raised by codex · 2026-10-07

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.

Use active phenotype METPO:1000059; METPO:1000198 mycorrhization is obsolete. Mutualism traitmech:000041 requires reciprocal benefit, which formation alone does not establish. Direct QuickGO checks identify GO:0085041 arbuscule as a cellular component below GO:0085035 haustorium. This attributed umbrella classification is not silently rejected: microbial haustorium formation traitmech:000663 and this formation phenotype are not asserted equivalent, disjoint or in a subclass relation. GO's root-cortex wording is narrower than the liverwort observations, and a structure is not an organism-level phenotype. No exact xrefs, synonyms or SSSOM mappings are asserted. Plant cells includes thallus cells; within-cell location does not mean free in host cytoplasm.

Separate formation, timing and nutrient-exchange mechanisms.

KNOWLEDGE GAP OPEN fungal-arbuscule-formation-and-function · raised by codex · 2026-10-07

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.

Do not infer nutrient flux, obligatory benefit, universal onset or lifespan from these morphology observations. Keep the 2019 main-text/supplement timing discrepancy open. The 2009 host membrane markers do not identify a fungal formation pathway. A protein-resolved causal graph needs direct perturbation evidence and authority-verified protein examples; it is deferred, not claimed absent. Extraradical branching alone does not satisfy this intracellular morphology definition.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added fungal arbuscule formation with two primary DOI citations, verbatim snippets and a culture-qualified fungal example. Ignored-and-hidden novelty and main/worktree/open-PR reservation checks support local ID 000664 and v540 block 1061700-1061799. Kept host markers, timing disagreements and ontology scope explicit; protein-level mechanism deferred.

Recorded curation sessions

  • · codex
    • CREATE — Add fungal arbuscule formation with root and thallus evidence

      Added traitmech:000664 as PROPOSED with DOI:10.1104/pp.109.141879 and DOI:10.3390/plants8060142, two directly checked verbatim snippets, a provenance-qualified MAFF520053 example and explicit ontology, host-marker and timing limits. Reserved v540 and METPO:1061700 within 1061700-1061799 after ignored-and-hidden main/worktree/open-PR checks. Writer dry run and 27 focused tests passed; broad validation and review remain pending. No causal graph is asserted.

    Read this curation session