identifier: traitmech:000406
label: PD-T7-4 system
definition: A phage defense system in which an organism possesses a PD-T7-4 locus
  represented by DefenseFinder as a single-profile model, PD-T7-4__PD-T7-4, and experimentally
  linked to protection against SECphi18, SECphi27, T3, and T7 when expressed in E.
  coli.
definition_source: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
trait_category: GENOMICS
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- traitmech:000209
synonyms:
- synonym_text: PD-T7-4
  synonym_type: RELATED_SYNONYM
  source: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
- synonym_text: PD-T7-4__PD-T7-4
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
evidence:
- reference: DOI:10.1038/s41564-022-01219-4
  snippet: Here we developed an experimental selection scheme agnostic to genomic
    context to identify defence systems in 71 diverse E. coli strains. Our results
    unveil 21 conserved defence systems, none of which were previously detected as
    enriched in defence islands.
  notes: Vassallo et al. developed the agnostic E. coli pangenome selection that uncovered
    PD-T7-4 and related conserved phage-defense systems.
- reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
  snippet: "Sensor: Unknown\n    Activator: Unknown\n    Effector: Unknown\n    PFAM:\
    \ PF13643"
  notes: The pinned DefenseFinder PD-T7-4 page has no sensor, activator, or effector
    annotation for PD-T7-4 and lists PF13643 as the associated Pfam profile.
- reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
  snippet: 'The PD-T7-4 is composed of 1 protein: PD-T7-4.'
  notes: The DefenseFinder wiki names PD-T7-4 as a single-protein system.
- reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
  snippet: 'The PD-T7-4 system in *Salinibacterium hongtaonis* (GCF_003065485.1, NZ_CP026951)
    is composed of 1 protein: PD-T7-4 (WP_108515598.1)'
  notes: The DefenseFinder wiki illustrates a predicted one-protein PD-T7-4 locus
    in RefSeq assembly GCF_003065485.1 on NZ_CP026951.
- reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
  snippet: "Vassallo_2022[<a href='https://doi.org/10.1038/s41564-022-01219-4'>Vassallo\
    \ et al., 2022</a>] --> Origin_0\n    Origin_0[Escherichia coli \n<a href='https://ncbi.nlm.nih.gov/protein/RRL46918.1'>RRL46918.1</a>]\
    \ --> Expressed_0[Escherichia coli]\n    Expressed_0[Escherichia coli] ----> SECphi18\
    \ & SECphi27 & T3 & T7"
  notes: The DefenseFinder experimental-validation diagram links Vassallo et al. to
    an E. coli PD-T7-4 source locus expressed in E. coli against SECphi18, SECphi27,
    T3, and T7.
- reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
  snippet: "subgraph Title4[Protects against]\n        SECphi18\n        SECphi27\n\
    \        T3\n        T7"
  notes: The DefenseFinder experimental-validation diagram lists SECphi18, SECphi27,
    T3, and T7 in the PD-T7-4 protects-against subgraph.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
  snippet: "PD-T7-4\tPD-T7-4\t1\t1\tPD-T7-4__PD-T7-4\t\t\t"
  notes: The DefenseFinder rules table models PD-T7-4 as a single-profile system requiring
    PD-T7-4__PD-T7-4.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: '| PD-T7-4__PD-T7-4                                 | PD-T7-4__PD-T7-4                                 |
    PD-T7-4                | Custom                  | 100    |'
  notes: The DefenseFinder HMM inventory records PD-T7-4__PD-T7-4 under the PD-T7-4
    system namespace.
causal_graphs:
- graph_id: pd_t7_4_locus_restricts_phages
  title: PD-T7-4 loci restrict SECphi18, SECphi27, T3, and T7
  description: Conservative system-level sketch linking possession of a PD-T7-4 locus
    to protection against SECphi18, SECphi27, T3, and T7.
  scope_status: NONMECHANISTIC
  scope_notes: The graph captures PD-T7-4 as a named DefenseFinder phage-defense system
    while leaving natural host breadth, the direct phage trigger, and the PF13643-associated
    effector mechanism unresolved.
  nodes:
  - node_id: pd_t7_4_locus
    label: PD-T7-4 locus
    node_type: GENETIC_ELEMENT
    description: A phage-defense locus represented by the PD-T7-4 DefenseFinder profile.
  - node_id: pd_t7_4_listed_phage_protection
    label: SECphi18, SECphi27, T3, and T7 protection
    node_type: BIOLOGICAL_PROCESS
    description: Protection against SECphi18, SECphi27, T3, and T7 by PD-T7-4.
  - node_id: pd_t7_4_system_trait
    label: PD-T7-4 system
    node_type: TRAIT
    grounding: traitmech:000406
    description: Possession of a genome-encoded PD-T7-4 phage-defense system.
  - node_id: phage_defense_system
    label: phage defense system
    node_type: TRAIT
    grounding: traitmech:000209
    description: Possession of one or more genome-encoded immune systems that inhibit
      bacteriophage infection.
  edges:
  - subject: pd_t7_4_locus
    predicate: contributes to
    predicate_id: RO:0002326
    object: pd_t7_4_listed_phage_protection
    description: The DefenseFinder wiki links a PD-T7-4 locus from Vassallo et al.
      to protection against SECphi18, SECphi27, T3, and T7, and DefenseFinder models
      PD-T7-4 through one mandatory profile.
    evidence:
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: "Sensor: Unknown\n    Activator: Unknown\n    Effector: Unknown\n \
        \   PFAM: PF13643"
      notes: The pinned DefenseFinder PD-T7-4 page has no sensor, activator, or effector
        annotation for PD-T7-4 and lists PF13643 as the associated Pfam profile.
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: 'The PD-T7-4 is composed of 1 protein: PD-T7-4.'
      notes: The DefenseFinder wiki names PD-T7-4 as a single-protein system.
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: "Vassallo_2022[<a href='https://doi.org/10.1038/s41564-022-01219-4'>Vassallo\
        \ et al., 2022</a>] --> Origin_0\n    Origin_0[Escherichia coli \n<a href='https://ncbi.nlm.nih.gov/protein/RRL46918.1'>RRL46918.1</a>]\
        \ --> Expressed_0[Escherichia coli]\n    Expressed_0[Escherichia coli] ---->\
        \ SECphi18 & SECphi27 & T3 & T7"
      notes: The DefenseFinder experimental-validation diagram links Vassallo et al.
        to an E. coli PD-T7-4 source locus expressed in E. coli against SECphi18,
        SECphi27, T3, and T7.
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: "subgraph Title4[Protects against]\n        SECphi18\n        SECphi27\n\
        \        T3\n        T7"
      notes: The DefenseFinder experimental-validation diagram lists SECphi18, SECphi27,
        T3, and T7 in the PD-T7-4 protects-against subgraph.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
      snippet: "PD-T7-4\tPD-T7-4\t1\t1\tPD-T7-4__PD-T7-4\t\t\t"
      notes: The DefenseFinder rules table models PD-T7-4 as a single-profile system
        requiring PD-T7-4__PD-T7-4.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: '| PD-T7-4__PD-T7-4                                 | PD-T7-4__PD-T7-4                                 |
        PD-T7-4                | Custom                  | 100    |'
      notes: The DefenseFinder HMM inventory records PD-T7-4__PD-T7-4 under the PD-T7-4
        system namespace.
  - subject: pd_t7_4_listed_phage_protection
    predicate: confers
    predicate_id: METPO:2007700
    object: pd_t7_4_system_trait
    description: Protection against SECphi18, SECphi27, T3, and T7 realizes the PD-T7-4
      system trait.
    evidence:
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: "Vassallo_2022[<a href='https://doi.org/10.1038/s41564-022-01219-4'>Vassallo\
        \ et al., 2022</a>] --> Origin_0\n    Origin_0[Escherichia coli \n<a href='https://ncbi.nlm.nih.gov/protein/RRL46918.1'>RRL46918.1</a>]\
        \ --> Expressed_0[Escherichia coli]\n    Expressed_0[Escherichia coli] ---->\
        \ SECphi18 & SECphi27 & T3 & T7"
      notes: The DefenseFinder experimental-validation diagram links Vassallo et al.
        to an E. coli PD-T7-4 source locus expressed in E. coli against SECphi18,
        SECphi27, T3, and T7.
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: "subgraph Title4[Protects against]\n        SECphi18\n        SECphi27\n\
        \        T3\n        T7"
      notes: The DefenseFinder experimental-validation diagram lists SECphi18, SECphi27,
        T3, and T7 in the PD-T7-4 protects-against subgraph.
  - subject: pd_t7_4_system_trait
    predicate: is a
    predicate_id: rdfs:subClassOf
    object: phage_defense_system
    description: PD-T7-4 system possession is a phage-defense-system trait.
    evidence:
    - reference: DOI:10.1038/s41564-022-01219-4
      snippet: Here we developed an experimental selection scheme agnostic to genomic
        context to identify defence systems in 71 diverse E. coli strains. Our results
        unveil 21 conserved defence systems, none of which were previously detected
        as enriched in defence islands.
      notes: Vassallo et al. developed the agnostic E. coli pangenome selection that
        uncovered PD-T7-4 and related conserved phage-defense systems.
    - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
      snippet: 'The PD-T7-4 is composed of 1 protein: PD-T7-4.'
      notes: The DefenseFinder wiki names PD-T7-4 as a single-protein system.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
      snippet: "PD-T7-4\tPD-T7-4\t1\t1\tPD-T7-4__PD-T7-4\t\t\t"
      notes: The DefenseFinder rules table models PD-T7-4 as a single-profile system
        requiring PD-T7-4__PD-T7-4.
discussions:
- discussion_id: pd-t7-4-mechanism-gap
  prompt: Resolve PD-T7-4 natural host breadth, direct phage trigger, and PF13643-associated
    effector mechanism before minting narrower PD-T7-4 mechanism traits.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: Vassallo et al. support PD-T7-4 as one of the conserved systems from
    an E. coli pangenome phage-defense selection, the DefenseFinder wiki maps the
    source locus to protection against SECphi18, SECphi27, T3, and T7, and DefenseFinder
    represents the system with one profile. Natural host breadth, the direct phage
    trigger, and effector logic remain unresolved.
  evidence:
  - reference: DOI:10.1038/s41564-022-01219-4
    snippet: Here we developed an experimental selection scheme agnostic to genomic
      context to identify defence systems in 71 diverse E. coli strains. Our results
      unveil 21 conserved defence systems, none of which were previously detected
      as enriched in defence islands.
    notes: Vassallo et al. developed the agnostic E. coli pangenome selection that
      uncovered PD-T7-4 and related conserved phage-defense systems.
  - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
    snippet: "Sensor: Unknown\n    Activator: Unknown\n    Effector: Unknown\n   \
      \ PFAM: PF13643"
    notes: The pinned DefenseFinder PD-T7-4 page has no sensor, activator, or effector
      annotation for PD-T7-4 and lists PF13643 as the associated Pfam profile.
  - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
    snippet: "Vassallo_2022[<a href='https://doi.org/10.1038/s41564-022-01219-4'>Vassallo\
      \ et al., 2022</a>] --> Origin_0\n    Origin_0[Escherichia coli \n<a href='https://ncbi.nlm.nih.gov/protein/RRL46918.1'>RRL46918.1</a>]\
      \ --> Expressed_0[Escherichia coli]\n    Expressed_0[Escherichia coli] ---->\
      \ SECphi18 & SECphi27 & T3 & T7"
    notes: The DefenseFinder experimental-validation diagram links Vassallo et al.
      to an E. coli PD-T7-4 source locus expressed in E. coli against SECphi18, SECphi27,
      T3, and T7.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
    snippet: "PD-T7-4\tPD-T7-4\t1\t1\tPD-T7-4__PD-T7-4\t\t\t"
    notes: The DefenseFinder rules table models PD-T7-4 as a single-profile system
      requiring PD-T7-4__PD-T7-4.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
    snippet: '| PD-T7-4__PD-T7-4                                 | PD-T7-4__PD-T7-4                                 |
      PD-T7-4                | Custom                  | 100    |'
    notes: The DefenseFinder HMM inventory records PD-T7-4__PD-T7-4 under the PD-T7-4
      system namespace.
  attaches_to:
  - causal_graphs#pd_t7_4_locus_restricts_phages
  posed_by: codex
  posed_date: '2026-09-27'
- discussion_id: pd-t7-4-defensefinder-article-registry-gap
  prompt: Recheck whether DefenseFinder adds a PD-T7-4 List_system_article.md row
    before using the article registry as direct PD-T7-4 model-to-paper evidence.
  kind: CURATION_TODO
  status: OPEN
  rationale: The pinned DefenseFinder wiki, rules table, and HMM inventory all represent
    PD-T7-4, but the pinned List_system_article.md registry omits a PD-T7-4 row. The
    PD-T7-4 record therefore cites the pinned wiki plus the DOI-backed Vassallo et
    al. screen instead of inventing a missing article-registry entry.
  evidence:
  - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/pd-t7-4.md
    snippet: 'The PD-T7-4 is composed of 1 protein: PD-T7-4.'
    notes: The DefenseFinder wiki names PD-T7-4 as a single-protein system.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
    snippet: "PD-T7-4\tPD-T7-4\t1\t1\tPD-T7-4__PD-T7-4\t\t\t"
    notes: The DefenseFinder rules table models PD-T7-4 as a single-profile system
      requiring PD-T7-4__PD-T7-4.
  - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
    snippet: '| PD-T7-4__PD-T7-4                                 | PD-T7-4__PD-T7-4                                 |
      PD-T7-4                | Custom                  | 100    |'
    notes: The DefenseFinder HMM inventory records PD-T7-4__PD-T7-4 under the PD-T7-4
      system namespace.
  posed_by: codex
  posed_date: '2026-09-27'
curation_history:
- timestamp: '2026-09-27T08:45:27Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Minted PD-T7-4 system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord
    under phage defense system after an ignored-and-hidden duplicate review found
    no exact live TraitMech, METPO, history, or prior proposal record; the replacement
    placeholder is reserved in proposals/metpo_traitmech_v283.
  llm_assisted: true
- timestamp: '2026-09-27T08:45:28Z'
  curator: codex
  action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP
  changes: Reviewed PD-T7-4 system canonical_examples and left them empty because
    the current sources support an E. coli accession-level experimental validation
    graph, a DefenseFinder system model, and a RefSeq Salinibacterium hongtaonis example,
    but not a direct native microbial isolate exemplar with experimentally verified
    endogenous PD-T7-4 activity. No paid research was used.
  llm_assisted: true