identifier: METPO:1000870
label: sporulation
definition: A phenotype that is relating to an organism's ability to form dormant,
  stress-resistant endospores.
definition_source: DOI:10.1146/annurev.genet.30.1.297
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000059
synonyms:
- synonym_text: General.keywords
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
- synonym_text: Physiology and metabolism.spore formation.spore formation
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
evidence:
- reference: DOI:10.1146/annurev.genet.30.1.297
  snippet: conversion of a growing cell into a two-cell-chamber sporangium
  notes: Supports sporulation as a developmental morphogenesis process producing a
    spore within a sporangium.
canonical_examples:
- taxon_id: NCBITaxon:1423
  taxon_label: Bacillus subtilis
  note: "endospore formation model"
  reference: PMID:32061128
- taxon_id: NCBITaxon:1488
  taxon_label: Clostridium acetobutylicum
  note: "anaerobic sporulation"
  reference: PMID:18631379
causal_graphs:
- graph_id: sporulation_spo0a_sigma_morphogenesis
  title: Sporulation Spo0A and sigma-factor morphogenesis
  description: Evidence-backed causal sketch linking environmental stress and Spo0A
    activation to asymmetric septation, compartment-specific sigma factors, forespore
    maturation, and endospore formation.
  nodes:
  - node_id: sporulation_trait
    label: sporulation
    node_type: TRAIT
    grounding: METPO:1000870
    description: Ability to undergo endospore-forming developmental differentiation.
  - node_id: nutrient_limitation
    label: nutrient limitation
    node_type: ENVIRONMENTAL_FACTOR
    description: Starvation or stress cue that can trigger sporulation.
  - node_id: spo0a_phosphorelay
    label: Spo0A phosphorelay
    node_type: GENE_OR_PROTEIN
    description: Phosphorelay-controlled master regulator of sporulation initiation.
  - node_id: asymmetric_septation
    label: asymmetric septation
    node_type: BIOLOGICAL_PROCESS
    description: Polar division generating mother-cell and forespore compartments.
  - node_id: compartment_sigma_factors
    label: compartment-specific sigma factors
    node_type: GENE_OR_PROTEIN
    description: Sporulation sigma factors such as sigma F, E, G, and K.
  - node_id: forespore_maturation
    label: forespore maturation
    node_type: BIOLOGICAL_PROCESS
    description: Developmental process converting the forespore into a mature endospore.
  - node_id: endospore
    label: endospore
    node_type: ORGANELLE
    description: Dormant stress-resistant spore produced by sporulating bacteria.
  - node_id: mother_cell_forespore
    label: mother cell and forespore
    node_type: CELLULAR_LOCALIZATION
    description: The two cellular compartments produced by asymmetric division during
      sporulation.
  - node_id: spoiiie_translocase
    label: SpoIIIE
    node_type: GENE_OR_PROTEIN
    description: DNA translocase that pumps the chromosome into the forespore during
      sporulation.
    grounding: UniProtKB:A0A100JQQ1
  - node_id: chromosome_translocation
    label: chromosome translocation
    node_type: BIOLOGICAL_PROCESS
    description: Movement of the trapped chromosome across the asymmetric septum into
      the forespore.
  - node_id: forespore_engulfment
    label: forespore engulfment
    node_type: BIOLOGICAL_PROCESS
    description: Mother-cell membrane migration around the forespore producing a cell-within-a-cell
      state.
  - node_id: cell_within_cell_state
    label: cell-within-a-cell state
    node_type: STATE
    description: Engulfed forespore fully enclosed within the mother-cell cytoplasm.
  - node_id: sigma_f
    label: sigma F
    node_type: GENE_OR_PROTEIN
    description: First compartment-specific sigma factor activated in the forespore.
    grounding: UniProtKB:E0J3M3
  - node_id: sigma_e
    label: sigma E
    node_type: GENE_OR_PROTEIN
    description: Mother-cell sigma factor activated downstream of sigma F.
    grounding: UniProtKB:A0A0C7NZS0
  - node_id: sigma_g
    label: sigma G
    node_type: GENE_OR_PROTEIN
    description: Late forespore sigma factor driving spore maturation and DNA protection.
  - node_id: sigma_k
    label: sigma K
    node_type: GENE_OR_PROTEIN
    description: Late mother-cell sigma factor controlling spore coat and cortex maturation.
    grounding: UniProtKB:A0A060N640
  - node_id: spore_dna_protection
    label: spore DNA protection
    node_type: BIOLOGICAL_PROCESS
    description: Protection of spore chromosomal DNA, e.g. via small acid-soluble
      (Ssp) proteins.
  - node_id: spore_coat_cortex
    label: spore coat and cortex
    node_type: CELLULAR_LOCALIZATION
    description: Protective spore envelope layers (cortex, coat, exosporium) deposited
      during maturation.
  - node_id: stress_resistance
    label: heat and chemical resistance
    node_type: QUALITY
    description: Resistance of the mature endospore to heat and chemical stress.
  edges:
  - subject: nutrient_limitation
    predicate: activates
    object: spo0a_phosphorelay
    description: Starvation and stress signals feed into Spo0A activation.
    evidence:
    - reference: DOI:10.1016/S1369-5274(00)00141-7
      snippet: steps that lead to activation of Spo0A
      notes: Supports Spo0A activation as the initiation control point for sporulation.
    predicate_id: RO:0002213
  - subject: spo0a_phosphorelay
    predicate: initiates
    object: asymmetric_septation
    description: Spo0A-dependent transcription initiates the morphological program
      that includes asymmetric septation.
    evidence:
    - reference: DOI:10.1146/annurev.genet.30.1.297
      snippet: activation of these sigma factors to landmark events in morphogenesis
      notes: Supports regulatory linkage between Spo0A/sigma activation and sporulation
        morphogenesis.
  - subject: asymmetric_septation
    predicate: establishes
    object: compartment_sigma_factors
    description: Asymmetric septation establishes mother-cell and forespore compartments
      with distinct sigma-factor programs.
    evidence:
    - reference: DOI:10.1128/MMBR.67.4.526-560.2003
      snippet: Compartmentalization of Gene Expression
      notes: Supports compartment-specific gene expression during spore formation.
  - subject: compartment_sigma_factors
    predicate: regulates
    object: forespore_maturation
    description: Sequential sigma-factor activity drives forespore development.
    evidence:
    - reference: DOI:10.1128/MMBR.67.4.526-560.2003
      snippet: forespore- and mother cell-specific transcription factors
      notes: Supports sigma-factor cascades as drivers of compartmental development.
    predicate_id: RO:0002211
  - subject: forespore_maturation
    predicate: produces
    object: endospore
    description: Forespore maturation produces a dormant endospore.
    evidence:
    - reference: DOI:10.1146/annurev.genet.30.1.297
      snippet: within which a spore is produced
      notes: Supports the developmental endpoint of sporulation.
    predicate_id: METPO:2000202
  - subject: endospore
    predicate: manifests as
    object: sporulation_trait
    description: Endospore production manifests the sporulation phenotype.
    evidence:
    - reference: DOI:10.1038/nrmicro2921
      snippet: production of a highly resistant dormant cell type known as the spore
      notes: Supports endospore production as the trait outcome.
    predicate_id: METPO:2007400
  - subject: asymmetric_septation
    predicate: produces
    object: mother_cell_forespore
    description: Asymmetric division produces distinct mother-cell and forespore compartments.
    evidence:
    - reference: DOI:10.1038/s41467-024-51654-6
      notes: via an asymmetric division into a forespore and mother cell (central
        defining morphogenesis edge).
    predicate_id: METPO:2000202
  - subject: spoiiie_translocase
    predicate: mediates
    object: chromosome_translocation
    description: SpoIIIE translocates the chromosome into the forespore after asymmetric
      septation.
    evidence:
    - reference: DOI:10.1038/s41467-024-51654-6
      notes: recruitment of SpoIIIE for chromosome translocation.
  - subject: forespore_engulfment
    predicate: creates
    object: cell_within_cell_state
    description: Engulfment of the forespore by the mother cell creates a cell-within-a-cell
      state.
    evidence:
    - reference: DOI:10.1038/s41467-024-51654-6
      notes: forespore engulfment, creating a cell-within-a-cell state.
    predicate_id: biolink:produces
  - subject: sigma_f
    predicate: activates
    object: sigma_e
    description: Forespore sigma F drives activation of mother-cell sigma E.
    evidence:
    - reference: DOI:10.1016/j.jbc.2024.107905
      notes: SigF activated first in the forespore; SigE activation in the mother
        cell depends on SigF.
    predicate_id: RO:0002213
  - subject: sigma_g
    predicate: drives
    object: spore_dna_protection
    description: Late forespore sigma G drives spore DNA protection during maturation.
    evidence:
    - reference: DOI:10.1038/s41467-024-51654-6
      notes: sigma G drives spore maturation and spore DNA protection via Ssp proteins.
  - subject: sigma_k
    predicate: controls
    object: spore_coat_cortex
    description: Mother-cell sigma K controls spore coat and cortex maturation.
    evidence:
    - reference: DOI:10.1038/s41467-024-51654-6
      notes: mother-cell sigma K controls spore coat and cortex maturation.
    predicate_id: RO:0002211
  - subject: spore_coat_cortex
    predicate: confers
    object: stress_resistance
    description: Deposition of cortex, coat and exosporium confers heat and chemical
      resistance.
    evidence:
    - reference: DOI:10.1038/s42003-024-06521-x
      notes: deposition of cortex, coat and exosporium (conferring heat and chemical
        resistance).
curation_history:
- timestamp: '2026-05-05T01:35:46.916642+00:00'
  curator: seed_from_metpo
  action: SEEDED_FROM_METPO
  changes: imported from data/raw/metpo.owl (CLASS)
  llm_assisted: false
- timestamp: '2026-05-11T21:00:00-07:00'
  curator: codex
  action: CURATED_WITH_LITERATURE
  changes: Added DOI-backed definition and causal graph for nutrient limitation, Spo0A
    phosphorelay, asymmetric septation, compartment sigma factors, forespore maturation,
    and endospore formation.
  llm_assisted: true
- timestamp: '2026-05-20T03:35:31Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2000202×1).
  llm_assisted: true
- timestamp: '2026-05-23T21:30:07Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2007400×1).
  llm_assisted: true
- timestamp: '2026-05-24T04:13:19Z'
  curator: claude
  action: RENAME_PREDICATE_LABELS
  changes: 'Renamed 1 causal-edge predicate label(s) to align with existing groundings:
    drives → regulates ×1.'
  llm_assisted: true
- timestamp: '2026-05-24T04:13:22Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002211×1).
  llm_assisted: true
- timestamp: '2026-06-13T21:03:26Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 1 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002213×1).
  llm_assisted: true
- timestamp: '2026-06-17T04:09:44Z'
  curator: claude
  action: REMOVE_REDUNDANT_SYNONYM
  changes: Removed 1 synonym(s) whose text duplicated the label (seeder redundancy;
    no information lost).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 7 evidence-backed generic edges (12 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:14Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 4 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (METPO:2000202×1, biolink:produces×1, RO:0002213×1, RO:0002211×1).
  llm_assisted: true
- timestamp: '2026-06-26T07:15:20Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 4 causal-node grounding field(s) via mappings/node_grounding.tsv
    (UniProtKB:A0A100JQQ1×1, UniProtKB:E0J3M3×1, UniProtKB:A0A0C7NZS0×1, UniProtKB:A0A060N640×1).
  llm_assisted: true