identifier: traitmech:000654
label: palmelloid formation
definition: A morphological phenotype in which algal cells form nonmotile multicellular
  groups by retention within a mother-cell wall or by adhesion through extracellular
  gelatinous material.
definition_source: DOI:10.1038/s41598-019-39558-8
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- METPO:1000059
evidence:
- reference: DOI:10.3390/ijms24098374
  snippet: the cells continue to divide within the mother cell, i.e., they are unable
    to separate and remain encased in a single membrane.
  notes: Suwannachuen et al. (2023), PMID:37176080, PMC10179368, Discussion 3.3. The
    quote is the authors' interpretation of enclosed dividing cells, not an abstract
    quote or a specific molecular mechanism. Results 2.5 and actual Figure 10 show
    CC-4414 palmelloids after high-light exposure in TAP medium. Methods 4.2 defines
    the percentage as palmelloid area divided by total cell area, not an individual-cell
    count. Larger aggregates are distinguished from palmelloids. CC-4414 provenance
    remains qualified in the discussion below.
- reference: DOI:10.3389/fpls.2022.911035
  snippet: a morphological state characterized by multiple, single cells encased in
    an outer limiting membrane
  notes: Szyszka-Mroz et al. (2022), PMID:36119589, PMC9470844, Introduction. The
    scientific abstract, growth Methods, morphology Results and actual Figure 1 were
    inspected. Palmelloids occur alongside single cells at permissive 8 C; stress
    is not a necessary condition. Internal cells may retain flagella. Shared enclosure
    does not establish a particular membrane chemistry or universal cytokinesis defect.
- reference: DOI:10.1038/s41598-019-39558-8
  snippet: the production of a gelatinous material that is secreted extracellularly,
    resulting in adhesion among cells and/or colonies
  notes: Herron et al. (2019), PMID:30787483, PMC6382799, Discussion. Directly retrieved
    full text explicitly uses palmelloid for both mother-wall retention and extracellular-material-mediated
    adhesion. This quote supports the second sense. The adjacent text describes palmelloids
    as nonmotile. This is terminology evidence, not a claim that the selected evolved
    isolates are natural canonical examples. The narrower enclosed-cell usage in the
    2022/2023 sources is retained with its source attribution.
canonical_examples:
- taxon_id: NCBITaxon:1653778
  taxon_label: Chlamydomonas priscui
  reference: DOI:10.3389/fpls.2022.911035
  note: Lake Bonney Antarctic isolate grown at 8 C in Bold's basal medium supplemented
    with 0.7 M NaCl, at 150 micromol photons m^-2 s^-1. Figure 1A,B and morphology
    Results show a mixed population of single cells and palmelloids, not every cell
    or growth stage. The Introduction identifies its natural lake origin. The source
    uses Chlamydomonas priscuii; NCBI Taxonomy lists that spelling as a synonym of
    the current species label Chlamydomonas priscui.
discussions:
- discussion_id: palmelloid-formation-scope-and-hierarchy
  prompt: Review a multicellular morphology parent and exact mappings.
  kind: CURATION_TODO
  status: OPEN
  rationale: 'Herron et al. (2019) explicitly includes mother-wall retention and extracellular-gelatinous-material
    adhesion in palmelloid usage, whereas the 2022/2023 sources emphasize enclosed
    cells. Preserve both documented senses in the unqualified class; review whether
    separate children are warranted. Retain phenotype METPO:1000059: cell shape METPO:1000666
    describes an individual cell and colony morphology METPO:1007062 is macroscopic.
    Obsolete cell arrangement METPO:1000046 and aggregate METPO:1000011 are not active
    parents. Biofilm formation traitmech:000053 requires surface attachment; rosette
    cell arrangement traitmech:000652 requires inward cell-pole orientation. Neither
    is required here. Palmelloid is not an exact synonym for any microbial aggregate,
    capsule, resting spore or normal transient pre-release sporangium. No xref or
    organism-level disjointness is asserted.'
  posed_by: codex
  posed_date: '2026-10-07'
- discussion_id: palmelloid-formation-mechanism-scope
  prompt: Resolve organism-specific cell-release mechanisms before graphing.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: A causal graph is deferred pending organism-specific perturbation and
    protein accession review. The 2023 proteome associations and proposed photoprotection
    do not establish that particular proteins cause palmelloid formation or that palmelloids
    are necessary for all high-light tolerance. Gene possession alone does not establish
    the phenotype. Do not transfer a cell-release mechanism to the extracellular-adhesion
    form. Four-to-sixteen cells, stress induction, loss of flagella, photoprotection
    and a particular cytokinesis or wall-remodelling defect are not universal requirements.
    For the wall-retained form, distinguish sustained enclosure from an ordinary division
    stage using organism-specific time courses; no universal persistence cutoff is
    asserted.
  posed_by: codex
  posed_date: '2026-10-07'
- discussion_id: palmelloid-formation-cc4414-provenance
  prompt: Reconcile CC-4414 provenance before canonical-example promotion.
  kind: CURATION_TODO
  status: OPEN
  rationale: 'The 2023 paper and Chlamydomonas Resource Center describe CC-4414/DN2
    as a field isolate: https://www.chlamycollection.org/product/cc-4414-wild-type-mt-dn2/
    . However, Flowers et al. (2015), Results accompanying Figure 2, reports extensive
    identity-by-descent with laboratory strains and raises possible cross-contamination
    while retaining a distinct chromosome-16 segment: https://academic.oup.com/plcell/article/27/9/2353/6206349
    . Both primary passages were directly read. This is a provenance uncertainty,
    not proof of engineering or contamination in the 2023 experimental stock. Preserve
    the observed high-light phenotype as qualified evidence, but omit CC-4414 from
    canonical examples pending reconciliation.'
  posed_by: codex
  posed_date: '2026-10-07'
curation_history:
- timestamp: '2026-10-07T00:44:51Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Added palmelloid formation with two DOI-backed snippets, a condition-qualified
    Antarctic-isolate example, and explicit enclosure, mechanism and CC-4414 provenance
    boundaries. Ignored-and-hidden searches and structured METPO review found no exact
    record. Reserved METPO:1060700 in v530; existing records unchanged.
  llm_assisted: true
- timestamp: '2026-10-07T00:57:34Z'
  curator: codex
  action: CORRECTED_DEFINITION_SCOPE
  changes: 'Addressed issue #1767: the unqualified palmelloid label was narrower than
    documented usage. Added DOI:10.1038/s41598-019-39558-8 and its verified snippet,
    broadened the definition to include extracellular-material adhesion, and retained
    source-specific scope and mechanism distinctions. Canonical example unchanged.'
  llm_assisted: true