identifier: traitmech:000081
label: viable but nonculturable state
definition: A dormancy state in which cells remain viable and minimally metabolically
  active but lose the ability to grow on routine culture media, regaining culturability
  upon resuscitation.
definition_source: DOI:10.1111/j.1574-6976.2009.00200.x
trait_category: PHYSIOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- traitmech:000080
synonyms:
- synonym_text: VBNC state
  synonym_type: RELATED_SYNONYM
  source: DOI:10.1111/j.1574-6976.2009.00200.x
evidence:
- reference: DOI:10.1111/j.1574-6976.2009.00200.x
  notes: Oliver reviews the viable-but-nonculturable state, in which stressed cells
    stay viable yet unculturable until resuscitated.
- reference: DOI:10.1038/nrmicro2504
  notes: Lennon & Jones frame the VBNC state within the broader microbial dormancy
    seed-bank concept.
canonical_examples:
- taxon_id: NCBITaxon:672
  taxon_label: Vibrio vulnificus
  note: "Canonical exemplar of the viable-but-nonculturable (VBNC) state."
  reference: PMID:7618874
causal_graphs:
- graph_id: vbnc_stress_induced_dormancy
  title: Stress-induced viable-but-nonculturable state
  description: Evidence-backed causal sketch linking stress to a dormant viable-but-nonculturable
    state that resuscitates later.
  nodes:
  - node_id: vbnc_trait
    label: viable but nonculturable state
    node_type: TRAIT
    grounding: traitmech:000081
    description: Viable, minimally active, non-culturable dormant state.
  - node_id: stress
    label: environmental stress
    node_type: ENVIRONMENTAL_FACTOR
    description: Stress driving cells into the VBNC state.
  - node_id: dormancy_process
    label: dormancy process
    node_type: BIOLOGICAL_PROCESS
    grounding: GO:0022611
    description: Entry into a reversible quiescent state.
  - node_id: oxidative_stress
    label: oxidative stress / ROS accumulation
    node_type: BIOLOGICAL_PROCESS
    description: Reactive oxygen species accumulation acting as a major VBNC trigger.
  - node_id: ppgpp
    label: (p)ppGpp
    node_type: CHEMICAL
    description: Alarmone nucleotide accumulating during VBNC entry, mediating the
      stringent response.
  - node_id: stress_resistance
    label: stress resistance
    node_type: BIOLOGICAL_PROCESS
    description: Enhanced tolerance to stress supporting VBNC maintenance.
  - node_id: rpos
    label: RpoS sigma factor
    node_type: GENE_OR_PROTEIN
    description: Stationary-phase/general stress sigma factor expressed in VBNC cells.
  - node_id: resuscitation
    label: resuscitation from VBNC
    node_type: BIOLOGICAL_PROCESS
    description: Recovery of culturability from the viable-but-nonculturable state.
  - node_id: atp
    label: ATP
    node_type: CHEMICAL
    description: Cellular ATP whose residual availability drives resuscitation metabolism.
  - node_id: nad_synthesis
    label: NAD+ biosynthesis
    node_type: BIOLOGICAL_PROCESS
    description: NAD+ synthesis during the resuscitating lag phase.
  - node_id: tca_oxphos
    label: TCA cycle flux and oxidative phosphorylation
    node_type: BIOLOGICAL_PROCESS
    description: Central energy metabolism restored during resuscitation.
  edges:
  - subject: stress
    predicate: causes
    object: vbnc_trait
    description: Stress drives cells into the viable-but-nonculturable state.
    evidence:
    - reference: DOI:10.1111/j.1574-6976.2009.00200.x
      notes: Oliver reviews stress-induced entry into the VBNC state.
    predicate_id: biolink:causes
  - subject: dormancy_process
    predicate: enables
    object: vbnc_trait
    description: The VBNC state is a form of microbial dormancy.
    evidence:
    - reference: DOI:10.1038/nrmicro2504
      notes: Lennon & Jones frame VBNC within microbial dormancy.
    predicate_id: RO:0002327
  - subject: oxidative_stress
    predicate: promotes
    object: vbnc_trait
    description: Oxidative stress / ROS accumulation promotes entry into the VBNC
      state.
    evidence:
    - reference: DOI:10.3390/foods12061179
      notes: 'Oxidative stress is a major trigger: ROS increase during VBNC entry
        (review across foodborne pathogens, mechanistically broad).'
    predicate_id: RO:0002213
  - subject: ppgpp
    predicate: enhances
    object: stress_resistance
    description: (p)ppGpp accumulation enhances stress resistance during VBNC.
    evidence:
    - reference: DOI:10.3390/foods12061179
      notes: Accumulation of (p)ppGpp, enhancing stress resistance, supports the regulatory
        layer upstream of VBNC maintenance.
  - subject: stress_resistance
    predicate: contributes to
    object: vbnc_trait
    description: Enhanced stress resistance supports maintenance of the VBNC state.
    evidence:
    - reference: DOI:10.3390/foods12061179
      notes: Stress resistance enhanced via (p)ppGpp underlies persistence in the
        VBNC state.
    predicate_id: RO:0002326
  - subject: rpos
    predicate: required for
    object: resuscitation
    description: RpoS is required for resuscitation from the VBNC state.
    evidence:
    - reference: DOI:10.3390/microorganisms12010039
      notes: RpoS is expressed in VBNC cells and required for resuscitation; RpoS
        mutants fail to resuscitate.
  - subject: atp
    predicate: promotes
    object: resuscitation
    description: ATP availability promotes resuscitation efficiency from VBNC.
    evidence:
    - reference: DOI:10.1016/j.jare.2023.08.002
      notes: Higher ATP levels correlated with higher resuscitation efficiency.
    predicate_id: RO:0002213
  - subject: atp
    predicate: drives
    object: nad_synthesis
    description: Residual ATP drives NAD+ synthesis during the resuscitating lag phase.
    evidence:
    - reference: DOI:10.1016/j.jare.2023.08.002
      notes: Part of cellular ATP is consumed during the lag phase to synthesize NAD+.
  - subject: nad_synthesis
    predicate: restores
    object: tca_oxphos
    description: NAD+ synthesis restores TCA cycle flux and oxidative phosphorylation
      during resuscitation.
    evidence:
    - reference: DOI:10.1016/j.jare.2023.08.002
      notes: ATP-mediated NAD+ synthesis increases NAD+ availability, restoring TCA
        cycle flux and driving oxidative phosphorylation.
curation_history:
- timestamp: '2026-06-04T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed candidate PHYSIOLOGY trait (viable but nonculturable state); sub-variant
    of dormancy.
  llm_assisted: true
- timestamp: '2026-06-08T13:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (stress-induced VBNC) with GO node grounding
    and biolink/RO predicate groundings; promoted PROPOSED to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 7 evidence-backed generic edges (8 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:15Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 3 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002213×2, RO:0002326×1).
  llm_assisted: true