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fungal auxiliary cell formation

traitmech:000671 · CLASS · PROPOSED

A morphological phenotype in which an arbuscular mycorrhizal fungus forms auxiliary cells, typically clustered hyphal swellings, on mycelium outside plant tissue.

Trait evidence (3)

  • https://www.mycorrhizas.info/vam.html
    Hyphae of Scutellospora and Gigaspora species produce clustered swellings with spines or knobs called auxiliary cells.

    Mark Brundrett, Mycorrhizal Associations, version 2 (2008), C.1 and glossary F, directly read. Terminology support, not independent experimental replication. The glossary describes external hyphae and says ornamentation is frequent, not obligatory. Its unnamed Scutellospora soil-hyphae micrograph and separate line illustration were actually viewed; neither establishes a named culture example. Historical auxiliary-body, external-vesicle and accessory-body labels name structures, not automatically exact organismal-trait synonyms.

  • DOI:10.1111/j.1469-8137.2007.02345.x
    In G. margarita, auxiliary cells were formed on germ tubes

    Kuga et al. (2008), PMID:18194149; Results clause before Elemental analyses, directly read in publisher full text. Methods identify MAFF520054. The Results point to Figure 3a/i; captions were read but actual paper images and supplements were not inspected. The HTML temperature glyph renders as 25×C and remains unresolved rather than normalized to degrees. Organelle localization and nonspecific DAPI fluorescence do not establish a formation mechanism or a universal storage function.

  • DOI:10.1017/S0953756203008761
    Isolated auxiliary cells were shown to exhibit hyphal re-growth, but not root colonization, either in situ or in vitro.

    Declerck et al. (2004), PMID:15035509; scientific abstract retrieved directly from Europe PMC. It follows extraradical mycelium, auxiliary cells and spores of Scutellospora reticulata in root-organ culture. Ri T-DNA transformation concerns carrot roots, not an engineered fungus. Regrowth without root colonization is conditional on the tested assays, not universal noninfectivity. Resource reallocation is the authors' interpretation, not a direct flux measurement. Full paper, images and isolate provenance were not inspected; no additional canonical culture is assigned.

Provenance

Identifier source
TraitMech local identifier
Definition source
https://www.mycorrhizas.info/vam.html

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.

  • Gigaspora margarita NCBITaxon:4874 DOI:10.1111/j.1469-8137.2007.02345.x MAFF520054, Results and Fungal materials of Kuga et al. (2008): auxiliary cells on germ tubes. Methods describe white-clover propagation, membranes over 1% soil agar, 10 days in darkness and a separate nutrient-agar staining treatment; cultivation duration is not formation onset. The temperature glyph and actual Figure 3 images remain unverified. The directly retrieved NARO record https://www.gene.affrc.go.jp/databases-micro_search_detail_en.php?maff=520054 lists designation C, soybean-field soil, Saitama Japan, isolator S. Ban and depositor/identifier M. Saito as separate fields. These establish field-isolate provenance, not a composite quote or independent trait evidence. NCBI Taxonomy resolves species 4874, not culture reidentification. Table 1 of DOI:10.1264/jsme2.ME25040 retains C/520054; primer-dependent ASVs, including above-genus assignments, are not culture counts or proof of contamination, identity or this phenotype. Its figures and supplements were not inspected. This example does not assert the response of all strains or conditions.

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 parent and structure-versus-trait terminology.

CURATION TODO OPEN fungal-auxiliary-cell-scope · 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 below quality METPO:1000188; mycorrhization METPO:1000198 is obsolete. Arbuscular mycorrhizal identifies the fungal context, not a requirement for current host contact: the germ-tube observation is outside plant tissue. Internal mycorrhizal vesicle formation traitmech:000670, arbuscule formation traitmech:000664 and branched absorbing structure formation traitmech:000665 denote different architectures or locations. Not every hyphal swelling is an auxiliary cell; neither fungal chlamydospore formation traitmech:000658 nor membrane-vesicle formation is an exact substitute. External-vesicle and accessory-body usages remain attributed structure labels; no exact synonyms, xrefs, SSSOM equivalents or disjoint organism-level phenotypes are asserted. Typical clustering does not impose a minimum count on every observation.

Separate auxiliary-cell morphology, counting and function.

KNOWLEDGE GAP OPEN fungal-auxiliary-cell-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.

Keep individual compartments, clusters, hyphal biomass and spore counts distinct. Morphology or lipid content does not establish universal nutrient transfer, propagule function, lifespan, wall-layer number or obligate host dependence. Hyphal regrowth and root colonization are different endpoints. A protein-resolved formation graph is deferred pending direct causal perturbations and authority-verified fungal protein examples; it is not claimed biologically absent. Host transformation and sequence-profile assignments alone do not demonstrate the fungal formation mechanism.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added fungal auxiliary cell formation with two primary DOI sources, attributed morphology terminology, three verbatim snippets and a culture-qualified MAFF520054 example. Ignored-and-hidden novelty and current-main/worktree/complete-open-PR reservation checks support 000671 and v547 block 1062400-1062499. Kept external swellings separate from internal vesicles, BAS, spores, function and protein mechanism; existing records unchanged.

Recorded curation sessions

  • · codex
    • CREATE — Add source-qualified fungal auxiliary cell formation

      Minted traitmech:000671, PROPOSED MORPHOLOGY, with v547 block 1062400-1062499, three snippets, two primary DOI sources and Brundrett terminology. Qualified MAFF520054 by direct observation, collection provenance and taxon authority; separated morphology from function and retained two OPEN discussions. Ignored/hidden novelty and allocation scans covered 15 roots, all worktrees and complete four-open-PR heads. Existing records unchanged. Validated writer dry run/apply and 20 focused tests passed in 5.71 seconds; broader corpus, proposal, browser and CI checks are pending at creation and will be reported on the PR.

    Read this curation session