identifier: traitmech:000013
label: cadmium tolerant
definition: A metal tolerance in which an organism grows in the presence of elevated
  cadmium (Cd2+) concentrations, typically via cation-efflux resistance systems such
  as the czc determinant.
definition_source: PMID:12829273
trait_category: ENVIRONMENT
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- traitmech:000012
evidence:
- reference: DOI:10.1111/j.1365-2958.2009.06792.x
  snippet: CzcP exports transition metals Zn(2+), Cd(2+) and Co(2+)
  notes: The cobalt-zinc-cadmium (czc) efflux system of Cupriavidus metallidurans
    confers cadmium resistance.
- reference: DOI:10.3389/fmicb.2020.00047
  snippet: C. metallidurans BS1 conferred resistance to Zn2+ displaying a MIC of 20
    mM, Cd2+ (2.5 mM), Co2+ (20mM), Ni2+ (8 mM), As3+ (3.5 mM), Cu2+ (5 mM), Au3+
    (1 uM) and Pb2+ (1.7 mM)
  notes: 'Organism example: Cupriavidus metallidurans BS1 tolerates cadmium to a MIC
    of 2.5 mM.'
canonical_examples:
- taxon_id: NCBITaxon:119219
  taxon_label: Cupriavidus metallidurans
  note: "cadmium efflux resistance"
  reference: PMID:20463976
causal_graphs:
- graph_id: cadmium_tolerance_czc_efflux
  title: Cadmium tolerance via czc cation-efflux system
  description: Evidence-backed causal sketch linking the cobalt-zinc-cadmium (czc)
    efflux determinant to cytoplasmic cadmium detoxification.
  nodes:
  - node_id: cadmium_tolerant_trait
    label: cadmium tolerant
    node_type: TRAIT
    grounding: traitmech:000013
    description: Capacity to grow at elevated Cd(2+) concentrations.
  - node_id: cadmium_ion
    label: cadmium(2+) ion
    node_type: CHEMICAL
    grounding: CHEBI:48775
    description: Toxic transition-metal cation accumulating in the cytoplasm.
  - node_id: czc_efflux_system
    label: czc cation-efflux system
    node_type: GENE_OR_PROTEIN
    description: CzcCBA/CzcP machinery exporting Cd, Zn, and Co cations.
    grounding: UniProtKB:B0VPE1
  - node_id: cadmium_export
    label: cadmium ion transmembrane transport
    node_type: BIOLOGICAL_PROCESS
    grounding: GO:0030001
    description: Active export of Cd(2+) across the cytoplasmic membrane.
  - node_id: metallothionein_proteins
    label: metallothionein / thiol-rich metal-binding proteins
    node_type: GENE_OR_PROTEIN
    description: Cysteine-rich proteins that bind and sequester cytoplasmic Cd(2+).
  - node_id: cadmium_sequestration
    label: cadmium ion sequestration
    node_type: BIOLOGICAL_PROCESS
    description: Intracellular binding and sequestration of cadmium ions, lowering
      free cytoplasmic Cd(2+).
  - node_id: cada_ptype_atpase
    label: CadA P-type (P1B) ATPase
    node_type: GENE_OR_PROTEIN
    description: ATP-driven P1B-type efflux ATPase pumping Cd(II) from cytoplasm to
      periplasm.
  - node_id: zinc_ion
    label: zinc(2+) ion
    node_type: CHEMICAL
    description: Divalent metal cation that cross-induces the czc cadmium-resistance
      program.
    grounding: CHEBI:29105
  edges:
  - subject: cadmium_ion
    predicate: challenges
    object: cadmium_tolerant_trait
    description: Cytoplasmic cadmium is the toxic challenge the trait counters.
    evidence:
    - reference: DOI:10.3389/fmicb.2020.00047
      notes: Cupriavidus metallidurans BS1 tolerates Cd(2+) to a MIC of 2.5 mM.
    predicate_id: METPO:2007406
  - subject: czc_efflux_system
    predicate: enables
    object: cadmium_export
    description: CzcP exports cadmium together with zinc and cobalt cations.
    evidence:
    - reference: DOI:10.1111/j.1365-2958.2009.06792.x
      notes: CzcP exports transition metals Zn(2+), Cd(2+), and Co(2+).
    predicate_id: RO:0002327
  - subject: cadmium_export
    predicate: mitigates
    object: cadmium_ion
    description: Czc-mediated export depletes the cytoplasmic cadmium pool.
    evidence:
    - reference: DOI:10.1111/j.1365-2958.2009.06792.x
      notes: The czc efflux system of C. metallidurans confers cadmium resistance.
    predicate_id: METPO:2007407
  - subject: metallothionein_proteins
    predicate: enables
    object: cadmium_sequestration
    description: Thiol-rich metallothioneins bind and sequester cytoplasmic Cd(2+).
    evidence:
    - reference: DOI:10.1007/s40201-023-00887-6
      notes: Metallothioneins bind Cd(II); thiol-rich proteins mediate cadmium sequestration
        as a microbial resistance mechanism.
    predicate_id: RO:0002327
  - subject: cadmium_sequestration
    predicate: mitigates
    object: cadmium_ion
    description: Sequestration of cadmium lowers the free toxic cytoplasmic Cd(2+)
      pool.
    evidence:
    - reference: DOI:10.1007/s40201-023-00887-6
      notes: Metallothionein/thiol-rich sequestration removes free cytoplasmic Cd(II)
        as a detoxification mechanism.
    predicate_id: METPO:2007407
  - subject: cada_ptype_atpase
    predicate: enables
    object: cadmium_export
    description: CadA P1B-type ATPase uses ATP to pump Cd(II) from cytoplasm to periplasm.
    evidence:
    - reference: DOI:10.1007/s40201-023-00887-6
      notes: P-type (P1B) ATPases (CadA) use ATP to pump Cd(II) from cytoplasm to
        periplasm.
    predicate_id: RO:0002327
  - subject: zinc_ion
    predicate: induces
    object: czc_efflux_system
    description: Zinc cross-induces expression of the czc cation-efflux cadmium-resistance
      program.
    evidence:
    - reference: DOI:10.1007/s40201-023-00887-6
      notes: czc expression is induced by zinc; zinc exposure enhances cadmium resistance
        via the efflux program.
curation_history:
- timestamp: '2026-05-28T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed candidate ENVIRONMENT trait (cadmium tolerance) from literature
    research; metal-specific sub-variant of metal tolerant.
  llm_assisted: true
- timestamp: '2026-06-09T14:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (czc cadmium efflux) with CHEBI/GO node
    groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-14T06:38:14Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (UniProtKB:B0VPE1×1).
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 4 evidence-backed generic edges (4 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:21:09Z'
  curator: claude
  action: GROUND_CAUSAL_PREDICATES
  changes: Grounded 3 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv
    (RO:0002327×2, METPO:2007407×1).
  llm_assisted: true
- timestamp: '2026-06-24T17:23:30Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (CHEBI:29105×1).
  llm_assisted: true