identifier: METPO:1000872
label: non-spore forming
definition: A sporulation in which an organism lacks the ability to produce endospores.
definition_source: DOI:10.1155/2013/898106
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000870
synonyms:
- synonym_text: 'no'
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
- synonym_text: no_spore
  synonym_type: RELATED_SYNONYM
  source: metpo.owl
evidence:
- reference: DOI:10.1155/2013/898106
  snippet: S. aureus does not form spores
  notes: 'Organism example: Staphylococcus aureus is described as non-spore-forming.'
- reference: DOI:10.1146/annurev.genet.30.1.297
  snippet: activation of these sigma factors to landmark events in morphogenesis
  notes: Sporulation regulatory review supports the Spo0A/sigma cascade as the sporulation
    control program whose absence yields a non-spore-forming phenotype.
canonical_examples:
- taxon_id: NCBITaxon:562
  taxon_label: Escherichia coli
  note: "does not form spores"
  reference: https://www.ncbi.nlm.nih.gov/books/NBK8035/
- taxon_id: NCBITaxon:1280
  taxon_label: Staphylococcus aureus
  note: "non-spore-forming"
  reference: PMID:24628867
causal_graphs:
- graph_id: non_spore_forming_absent_spo0a_cascade
  title: Non-spore-forming absent Spo0A cascade
  description: DOI-backed graph linking absence or non-functionality of the Spo0A-initiated
    sporulation regulatory cascade to inability to form endospores.
  nodes:
  - node_id: non_spore_forming_trait
    label: non-spore forming
    node_type: TRAIT
    grounding: METPO:1000872
    description: Inability to produce endospores.
  - node_id: absent_spo0a_cascade
    label: absent Spo0A regulatory cascade
    node_type: BIOLOGICAL_PROCESS
    description: Absence or non-functionality of the Spo0A-initiated sporulation regulatory
      program (Spo0A master regulator and downstream sigma factors).
  - node_id: no_asymmetric_septation
    label: no asymmetric septation
    node_type: BIOLOGICAL_PROCESS
    description: Lack of the polar division step that generates a forespore compartment.
  - node_id: no_endospore_formation
    label: no endospore formation
    node_type: BIOLOGICAL_PROCESS
    description: Failure to produce a dormant, resistant endospore.
  - node_id: absent_spo0a_gene
    label: absence of spo0A gene
    node_type: GENE_OR_PROTEIN
    description: Lack of the spo0A master regulator gene; an excellent predictor of
      inability to sporulate.
  - node_id: loss_sporulation_genes
    label: loss of sporulation genes
    node_type: BIOLOGICAL_PROCESS
    description: Inactivation or loss of a considerable fraction of core sporulation
      genes.
  - node_id: low_spo0a_activity
    label: low or absent Spo0A activity
    node_type: MOLECULAR_FUNCTION
    description: Reduced or absent activity of the Spo0A master regulator of endospore
      formation.
  - node_id: loss_sporulation_capacity
    label: loss of sporulation capacity
    node_type: CAPACITY
    description: Loss of the capacity to undergo sporulation.
  - node_id: rap_phosphatases
    label: Rap phosphatases
    node_type: GENE_OR_PROTEIN
    description: Rap family phosphatases that dephosphorylate Spo0F in the sporulation
      phosphorelay.
  - node_id: spo0f_dephosphorylation
    label: dephosphorylation of Spo0F
    node_type: BIOLOGICAL_PROCESS
    description: Dephosphorylation of Spo0F reducing phosphate flow to Spo0A in the
      phosphorelay.
  - node_id: phosphorelay_disruption
    label: Spo0A phosphorelay disruption
    node_type: BIOLOGICAL_PROCESS
    description: Disruption of the KinA/KinB -> Spo0F -> Spo0B -> Spo0A phosphorelay
      that initiates sporulation.
  - node_id: no_sporulation_entry
    label: no entry into sporulation
    node_type: BIOLOGICAL_PROCESS
    description: Failure to enter the sporulation developmental program (arrest at
      stages 0/I).
  edges:
  - subject: absent_spo0a_cascade
    predicate: prevents
    object: no_asymmetric_septation
    description: Without the Spo0A/sigma cascade, asymmetric septation cannot be initiated.
    evidence:
    - reference: DOI:10.1146/annurev.genet.30.1.297
      snippet: activation of these sigma factors to landmark events in morphogenesis
      notes: Supports the Spo0A/sigma cascade as the gatekeeper of sporulation morphogenesis.
    predicate_id: RO:0002212
  - subject: no_asymmetric_septation
    predicate: prevents
    object: no_endospore_formation
    description: Without asymmetric septation, the forespore compartment and subsequent
      endospore cannot be produced.
    evidence:
    - reference: DOI:10.1146/annurev.genet.30.1.297
      snippet: activation of these sigma factors to landmark events in morphogenesis
      notes: Supports asymmetric septation as a required step for endospore formation.
    predicate_id: RO:0002212
  - subject: no_endospore_formation
    predicate: manifests as
    object: non_spore_forming_trait
    description: Failure to produce endospores manifests the non-spore-forming trait.
    evidence:
    - reference: DOI:10.1155/2013/898106
      snippet: S. aureus does not form spores
      notes: Supports the trait endpoint in a representative organism.
    predicate_id: METPO:2007400
  - subject: absent_spo0a_gene
    predicate: predicts
    object: non_spore_forming_trait
    description: Absence of spo0A is an excellent predictor of inability to sporulate.
    evidence:
    - reference: DOI:10.1128/jb.00079-22
      notes: 'Comparative genomics of 180 genomes: spo0A present in all 76 sporeformers;
        its absence predicts non-sporulation.'
  - subject: loss_sporulation_genes
    predicate: causes
    object: non_spore_forming_trait
    description: Loss of a considerable fraction of sporulation genes yields an asporogenic
      phenotype.
    evidence:
    - reference: DOI:10.1111/1462-2920.16145
      notes: Asporogenic phenotypes can result from inactivation or loss of a considerable
        fraction of sporulation genes (generic edge).
    predicate_id: biolink:causes
  - subject: low_spo0a_activity
    predicate: causes
    object: loss_sporulation_capacity
    description: Low or absent Spo0A activity abolishes sporulation capacity.
    evidence:
    - reference: DOI:10.3389/fmicb.2021.630573
      notes: Spo0A is the master regulator of endospore formation; elevated Spo0A~P
        is required to trigger sporulation.
    predicate_id: biolink:causes
  - subject: loss_sporulation_capacity
    predicate: manifests as
    object: non_spore_forming_trait
    description: Loss of sporulation capacity manifests the non-spore-forming phenotype.
    evidence:
    - reference: DOI:10.3389/fmicb.2021.630573
      notes: Failure to produce/activate Spo0A prevents sporulation, yielding the
        non-spore-forming trait.
    predicate_id: METPO:2007400
  - subject: rap_phosphatases
    predicate: dephosphorylates
    object: spo0f_dephosphorylation
    description: Rap phosphatases directly dephosphorylate Spo0F.
    evidence:
    - reference: DOI:10.1038/s41522-024-00594-6
      notes: Rap phosphatases directly dephosphorylate Spo0F (generic to Bacillus
        phosphorelay logic).
  - subject: spo0f_dephosphorylation
    predicate: decreases activation of
    object: low_spo0a_activity
    description: Dephosphorylation of Spo0F reduces phosphate flow to Spo0A, decreasing
      its activation.
    evidence:
    - reference: DOI:10.1038/s41522-024-00594-6
      notes: Reduced phosphate flow to Spo0A in the sporulation phosphorelay (corroborated
        by DOI:10.3390/microorganisms11081928).
  - subject: phosphorelay_disruption
    predicate: prevents
    object: no_sporulation_entry
    description: Disruption of the KinA/KinB -> Spo0F -> Spo0B -> Spo0A phosphorelay
      arrests entry into sporulation.
    evidence:
    - reference: DOI:10.3390/microorganisms11081928
      notes: The phosphorelay signals the start of sporulation; mutants arrest at
        stages 0/I when initiation fails.
    predicate_id: RO:0002212
  - subject: no_sporulation_entry
    predicate: manifests as
    object: non_spore_forming_trait
    description: Failure to enter sporulation manifests the non-spore-forming phenotype.
    evidence:
    - reference: DOI:10.3390/microorganisms11081928
      notes: Arrest at sporulation initiation produces the non-spore-forming endpoint.
    predicate_id: METPO:2007400
curation_history:
- timestamp: '2026-05-05T01:35:46.917903+00:00'
  curator: seed_from_metpo
  action: SEEDED_FROM_METPO
  changes: imported from data/raw/metpo.owl (CLASS)
  llm_assisted: false
- timestamp: '2026-05-06T14:40:41-07:00'
  curator: codex
  action: CURATED_WITH_ORGANISM_EXAMPLE
  changes: Added Staphylococcus aureus organism example with DOI-backed evidence.
  llm_assisted: true
- timestamp: '2026-05-11T23:00:00-07:00'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added DOI-backed causal graph linking absence of Spo0A regulatory cascade
    and asymmetric septation to the non-spore-forming phenotype.
  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: '2026-06-13T21:03:26Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002212×2).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 8 evidence-backed generic edges (8 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:13Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 5 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (biolink:causes×2, METPO:2007400×2, RO:0002212×1).
  llm_assisted: true