identifier: traitmech:000184
label: holdfast
definition: A morphology trait in which a bacterial cell produces a localized polar
  adhesive matrix called a holdfast that mediates permanent attachment to surfaces.
definition_source: DOI:10.1128/jb.00276-19
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- METPO:1000059
synonyms:
- synonym_text: holdfast adhesin
  synonym_type: RELATED_SYNONYM
  source: DOI:10.1128/jb.00276-19
evidence:
- reference: DOI:10.1128/jb.00276-19
  snippet: Caulobacter crescentus synthesizes a polysaccharide-based adhesin known
    as the holdfast at one of its cell poles, which enables tight attachment to exogenous
    surfaces.
  notes: Hershey et al. support holdfast as a Caulobacter polar polysaccharide-based
    adhesin mediating tight surface attachment.
- reference: DOI:10.1128/jb.00276-19
  snippet: Glucose, 3-O-methylglucose, mannose, N-acetylglucosamine, and xylose were
    detected in our extracts.
  notes: The compositional analysis supports the holdfast matrix as a bacterial polysaccharide-rich
    adhesive.
- reference: DOI:10.1128/jb.00273-22
  snippet: Species of the Caulobacterales produce a specialized polar adhesin, holdfast,
    which is required for permanent attachment to surfaces.
  notes: Chepkwony et al. support holdfast as a specialized polar Caulobacterales
    adhesin required for permanent attachment.
canonical_examples:
- taxon_id: NCBITaxon:155892
  taxon_label: Caulobacter vibrioides
  note: Model freshwater Caulobacter species, long called Caulobacter crescentus,
    that produces a polar holdfast.
  reference: DOI:10.1128/jb.00276-19
discussions:
- discussion_id: holdfast-exact-xref-gap
  prompt: Resolve exact external ontology xrefs for the bacterial holdfast morphology
    trait.
  kind: CURATION_TODO
  status: OPEN
  rationale: The pinned METPO snapshot contains only the deprecated METPO:1000158
    obsolete holdfast class; no active METPO, GO, or OBO class was accepted as an
    exact equivalent for this bacterial adhesive-matrix trait.
  posed_by: codex
  posed_date: '2026-09-14'
curation_history:
- timestamp: '2026-09-14T06:26:17Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Minted holdfast as a DOI-backed TraitRecord after a repository-wide duplicate
    review covering ignored and hidden files; live METPO has no active exact holdfast
    class and the placeholder is reserved in proposals/metpo_traitmech_v61.
  llm_assisted: true