identifier: traitmech:000662 label: fungal rhizomorph formation definition: A morphological phenotype in which a fungus forms root-like, multihyphal structures through coordinated hyphal growth. definition_source: DOI:10.1016/j.fgb.2009.04.005 trait_category: MORPHOLOGY term_kind: CLASS mapping_status: PROPOSED parent_traits: - METPO:1000059 evidence: - reference: DOI:10.1016/j.fgb.2009.04.005 snippet: Rhizomorphs of wood-decay basidiomycetes are root-like structures produced by the coordinated growth of thousands of hyphae. notes: Yafetto, Davis and Money (2009), PMID:19427390; scientific abstract retrieved directly through Europe PMC. The naming sentence supports the formation phenotype, not a universal hyphal-count threshold. Armillaria gallica cultures were tested in media of different gel strengths. The reported 760 kPa is an osmolality-derived turgor estimate, whereas 40-300 kPa describes pressure corresponding to measured tip forces. These are distinct readouts, not trait thresholds. Full text, figures, supplements and isolate provenance were not inspected; no canonical example is inferred from this abstract. - reference: DOI:10.1016/j.mycres.2005.09.006 snippet: Air pores develop near the inoculum plug shortly after inoculation, arising directly from the mycelium, and rhizomorphs are initiated from them. notes: Pareek, Allaway and Ashford (2006), PMID:16376531; scientific abstract checked against the directly retrieved PDF and Europe PMC abstract. Methods, Results, Discussion, Table 1 and actual Figures 9-17 were inspected. Results place first tips on day 6, but Table 1 reports tips on day 5; no exact onset is asserted. Table 1 counts tips and air pores on five plates, not organisms. The main oxygen-conductance assay used cut rhizomorph ends; it does not establish intact-rind permeability or universal oxygen adaptation. Air pores and rhizomorphs are distinct structures. Remaining figure images and supplements were not inspected. - reference: DOI:10.1186/s12862-017-0877-3 snippet: All armillarioid species have the capacity to form rhizomorphs in culture, but only the later diverging lineages have been observed to form them in nature notes: Koch et al. (2017), PMID:28122504, PMC5264464; directly retrieved full-text XML, Discussion subsection The rise of rhizomorphs and Table 2. The quoted clause precedes a parenthetical figure/table citation. This is the authors' comparative summary, partly based on earlier literature, not a new formation experiment on every species. They explicitly describe unmelanized rhizomorphs in culture. Field non-observation is not biological absence; the summary does not establish expression in every strain or condition. Full Methods, actual figures, supplements and additional isolate provenance were not inspected. - reference: DOI:10.3114/fuse.2024.14.03 snippet: Many rhizomorph-forming fungi occur in the litter on the forest floor (ground species), while other species make aerial rhizomorph networks (epiphytic species). notes: Oliveira et al. (2024), PMID:39830290, PMC11739697; Introduction read directly in PMC HTML after the Europe PMC XML endpoint failed. This terminology passage supports not restricting formation to underground growth. These authors adopt a narrow melanized, differentiated, organized-tip concept and contrast Singer's white rhizomorph usage with mycelial cords. That is their attributed account; the original Singer/Rayner sources were not retrieved. Abstract, Introduction and selected taxonomic text/captions were read, but actual figures, supplements and the full Methods were not inspected. No additional canonical taxon or exact cord synonym is asserted. canonical_examples: - taxon_id: NCBITaxon:153913 taxon_label: Armillaria luteobubalina reference: DOI:10.1016/j.mycres.2005.09.006 note: Isolate 930199KGS in Pareek et al. (2006), Fungal material and culture conditions, Results and Figures 9-17. Primary Methods at https://doi.org/10.1016/j.mycres.2005.09.006 identify the University of Western Sydney collection culture as originating from fruit bodies collected at Gore Hill Park, North Sydney, in June 1993. Rhizomorph development was observed on malt-marmite agar in darkness at 23 C. The Methods provenance and actual images were inspected; natural origin is not inferred from a wild-type label. NCBI Taxonomy confirms the species ID, label and rank. This is a qualified culture observation, not evidence for every strain or condition. discussions: - discussion_id: fungal-rhizomorph-scope-and-hierarchy prompt: Resolve rhizomorph/cord terminology and a closer fungal parent. kind: CURATION_TODO status: OPEN rationale: 'Use phenotype METPO:1000059. Mycelial growth traitmech:000074 is explicitly bacterial; filament shaped METPO:1000674 is a cell-shape class; rhizoid colony METPO:1007068 and filamentous colony METPO:1007066 concern colony outlines. None is an exact fungal multihyphal formation record. Hyphal anastomosis traitmech:000605 denotes fusion and fungal sclerotium formation traitmech:000660 denotes compact resting bodies. Koch et al. (2017) use rhizomorph for unmelanized culture structures, whereas Oliveira et al. (2024) adopt the narrower melanized, organized-tip sense and distinguish mycelial cords. The broad formation definition does not settle that anatomical boundary: retain the source attribution and do not assert exact cord/strand synonyms, a universal pigment requirement or an underground-only habitat. A closer fungal growth-form parent and external equivalences require upstream review; no xrefs or SSSOM mappings are asserted. Fungal mycelial cord formation traitmech:000669 now represents the diffuse-front aggregation sense defined by Boddy et al. (2009), DOI:10.1007/s10267-008-0450-4, rather than silently equating the two names. Its experimental examples do not resolve all historical usage. Keep this terminology/hierarchy question OPEN: neither equivalence, a parent-child relationship nor organism-level disjointness is asserted.' posed_by: codex posed_date: '2026-10-07' - discussion_id: fungal-rhizomorph-formation-and-function prompt: Separate formation from transport, invasion and gene mechanisms. kind: KNOWLEDGE_GAP status: OPEN rationale: Formation does not by itself prove pathogenicity, low-oxygen adaptation, a fixed invasion force or a universal hollow canal. Pareek et al. distinguish air pores from rhizomorphs; oxygen measurements on cut structures do not show intact-rind permeability. Their Results/Table 1 onset discrepancy remains unresolved. Culture versus field observations and hyphal/tip counts require explicit conditions and denominators. Physical growth and aeration have experimental support, but a formation-regulatory graph requires further primary perturbation evidence and authority-verified protein examples. No complete protein pathway is inferred from expression, gene possession, osmolyte composition or structure alone. The graph is deferred, not claimed to be biologically absent. posed_by: codex posed_date: '2026-10-07' curation_history: - timestamp: '2026-10-07T09:59:27Z' curator: codex action: MINTED_TRAITMECH_ID changes: Added fungal rhizomorph formation with four directly checked source snippets, a provenance-qualified 930199KGS example and explicit terminology, hierarchy and experimental limits. Ignored-and-hidden searches found no exact existing trait. Reserved METPO:1061500 in v538; existing records unchanged and protein-level formation mechanism deferred. llm_assisted: true - timestamp: '2026-10-07T22:14:44Z' curator: codex action: LINKED_SCOPE_DISCUSSION changes: Linked the rhizomorph/cord scope discussion to new traitmech:000669. Preserved the attributed conflicting usages, OPEN status and all existing identity, evidence and example fields; no synonym, hierarchy or disjointness axiom was introduced. llm_assisted: true