identifier: traitmech:000653
label: pseudohyphal growth
definition: A morphological phenotype in which elongated budding yeast cells remain
  attached in chains with constrictions at the junctions between cells.
definition_source: DOI:10.1590/S1517-83822013005000056
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- METPO:1000059
evidence:
- reference: DOI:10.1590/S1517-83822013005000056
  snippet: pseudohyphae formed branched chains of elongated blastoconidial cells retaining
    constrictions at the septal junctions
  notes: Staniszewska et al. (2013), PMID:24516422, PMC3910194, Results subsection
    Pseudohyphae. Full-text XML, strain/culture Methods, Table 1 and actual Figure
    4 were inspected. Clinical isolate 82 forms pseudohyphae mixed with true hyphae
    after six hours in serum; later hyphal predominance is not a contradictory same-time
    observation. The quote is from Results, not the abstract. Numerical morphology
    indices and serum induction conditions are study-specific, not universal trait
    thresholds.
- reference: DOI:10.1016/0092-8674(92)90079-r
  snippet: Cells become long and thin and form pseudohyphae that grow away from the
    colony and invade the agar medium.
  notes: Gimeno et al. (1992), PMID:1547504, scientific abstract directly retrieved
    through Europe PMC. Diploid Saccharomyces cerevisiae under nitrogen starvation
    changes morphology and budding pattern. The abstract also reports RAS2, SHR3 and
    RSR1/BUD1 perturbations. Full text and figures were not verified. Diploidy, nitrogen
    starvation and agar invasion describe this study, not necessary conditions for
    every pseudohyphal yeast.
canonical_examples:
- taxon_id: NCBITaxon:5476
  taxon_label: Candida albicans
  reference: DOI:10.1590/S1517-83822013005000056
  note: Wild-type clinical bloodstream isolate 82, cultured in undiluted human serum
    for six hours at 37 C. Results and Figure 4A,C show pseudohyphae in a mixed population,
    not every cell or culture stage. Table 1 and Methods identify its clinical origin
    separately from the engineered comparison strains. This is an in-vitro morphology
    observation, not proof of pseudohyphae in the patient's bloodstream. NCBI Taxonomy
    resolves the species identifier and label.
discussions:
- discussion_id: pseudohyphal-growth-scope-and-hierarchy
  prompt: Review a yeast growth-form parent and exact external mappings.
  kind: CURATION_TODO
  status: OPEN
  rationale: Retain phenotype METPO:1000059. Mycelial growth traitmech:000074 is explicitly
    bacterial. Filament shaped METPO:1000674 has a broad hypha-like description but
    is classified under individual cell shape METPO:1000666; this record denotes attached
    budding-cell chains, not merely an elongated cell. Colony morphology METPO:1007062
    concerns macroscopic colonies, not this microscopic growth form. Obsolete cell
    arrangement METPO:1000046 is not an active parent. Do not equate pseudohyphae
    with uninterrupted true hyphae, disordered aggregation, or every filamentous form.
    No exact synonym or xref is asserted. Different forms may coexist in one culture;
    this is not organism-level disjointness.
  posed_by: codex
  posed_date: '2026-10-06'
- discussion_id: pseudohyphal-growth-mechanism-scope
  prompt: Resolve organism-specific morphogenesis mechanisms before graphing.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: A causal graph is deferred pending full perturbation and protein-accession
    review, not because mechanisms are unknown. Do not transfer the 1992 budding-pattern
    or ploidy constraints to all yeasts, or treat the Candida comparison mutants as
    natural canonical examples. Gene possession alone does not establish pseudohyphal
    growth. Serum exposure, branching, agar invasion, numerical aspect-ratio cutoffs
    and virulence are not universal requirements. The 2013 study's bloodstream pathogenesis
    discussion does not directly demonstrate a pseudohypha-specific virulence mechanism.
    Additional Saccharomyces examples need direct strain-provenance review.
  posed_by: codex
  posed_date: '2026-10-06'
curation_history:
- timestamp: '2026-10-06T23:54:28Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Added pseudohyphal growth with two DOI-backed snippets, a condition-qualified
    clinical-isolate example, and explicit growth-form and mechanism limits. Ignored-and-hidden
    novelty searches and structured METPO review found no exact record. Reserved METPO:1060600
    in v529; existing records unchanged.
  llm_assisted: true