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AbiT system

traitmech:000230 · CLASS · PROPOSED

An abortive infection system in which an organism possesses the two-gene pED1 abiT locus whose constitutively cotranscribed abiTi and abiTii genes encode an AbiTi-AbiTii phage-resistance module that acts late in the 936/P335 lactococcal phage lytic cycle.

Trait evidence (8)

  • DOI:10.1128/JB.184.22.6325-6332.2002
    Here, we describe the isolation and characterization of a novel Abi mechanism encoded by plasmid pED1 from L. lactis

    Bouchard et al. identified the plasmid pED1-encoded AbiT abortive-infection mechanism in Lactococcus lactis.

  • DOI:10.1128/JB.184.22.6325-6332.2002
    The system is composed of two constitutively cotranscribed genes encoding putative proteins of 127 and 213 amino acids, named AbiTi and AbiTii, respectively

    Bouchard et al. support defining AbiT around the paired abiTi and abiTii host genes rather than around a single gene.

  • DOI:10.1128/JB.184.22.6325-6332.2002
    The fact that resistant cells do not survive phage infection proves that the antiphage system carried by pED1 is an Abi mechanism. It was therefore named AbiT.

    Bouchard et al. placed the pED1 phage-resistance determinant in the abortive-infection class and named it AbiT.

  • DOI:10.1128/JB.184.22.6325-6332.2002
    Two genes are responsible for the antiphage activity of AbiT

    Bouchard et al. support a two-gene genetic basis for AbiT phage resistance.

  • DOI:10.1128/JB.184.22.6325-6332.2002
    It appears that AbiT affects DNA replication and also prevents effective encapsidation

    Bouchard et al. connect AbiT to both impaired phage DNA replication and ineffective phage encapsidation.

  • DOI:10.1128/AEM.01755-12
    AbiT-resistant phage mutants derived from the wild-type AbiT-sensitive lactococcal phages p2, bIL170, and P008 were isolated and characterized

    Labrie et al. generated AbiT-resistant mutants from three sensitive 936-group Lactococcus phages.

  • DOI:10.1128/AEM.01755-12
    three distinct phage genes involved in AbiT activity were identified

    Labrie et al. found that AbiT sensitivity maps to multiple nonhomologous phage genes rather than one universal phage escape determinant.

  • DOI:10.1128/AEM.01755-12
    AbiT blocks capsid protein synthesis of the wild-type phage, while it does not affect the resistant phage p2.t3, mutated in the capsid gene

    Labrie et al. connect a p2 major-capsid-protein escape mutation to restoration of capsid protein synthesis in the presence of AbiT.

AbiT activity blocks late phage development

Evidence-backed process sketch linking the two-gene abiT locus to AbiTi-AbiTii antiphage activity, impaired phage DNA replication or capsid production, restricted phage propagation, and abortive-infection system possession.

NONMECHANISTIC · The graph captures AbiT at the system level without asserting a molecular function for AbiTi or AbiTii, the exact host target, the direct phage activator, or that every AbiT-insensitive phage mutates the same phage gene.

AbiT activity blocks late phage development Interactive directed graph showing evidence-backed causal relationships for AbiT system.

Edge evidence

  • abiT locus contributes to AbiTi-AbiTii antiphage activity RO:0002326

    The abiT locus carries abiTi, abiTii, and the promoter required for the complete phage-resistance phenotype.

    • DOI:10.1128/JB.184.22.6325-6332.2002 Two genes are responsible for the antiphage activity of AbiT Bouchard et al. showed that both abiT genes are required for full AbiT activity.
  • AbiTi-AbiTii antiphage activity contributes to interrupted late phage development RO:0002326

    AbiT activity interferes with late phage development after early phage gene expression.

    • DOI:10.1128/JB.184.22.6325-6332.2002 It appears that AbiT affects DNA replication and also prevents effective encapsidation Bouchard et al. found reduced DNA replication and failed encapsidation in AbiT-containing infected cells.
    • DOI:10.1128/AEM.01755-12 AbiT blocks capsid protein synthesis of the wild-type phage, while it does not affect the resistant phage p2.t3, mutated in the capsid gene Labrie et al. refine the AbiT phenotype by linking wild-type p2 capsid protein synthesis blockage to an AbiT-sensitive capsid gene.
  • interrupted late phage development contributes to restricted phage propagation RO:0002326

    Failed phage DNA maturation or capsid production limits completion of the phage lytic cycle.

    • DOI:10.1128/JB.184.22.6325-6332.2002 The monitoring of the intracellular phage infection process by DNA replication, gene expression, and electron microscopy as well as the study of phage mutants by genome mapping indicated that AbiT is likely to act at a later stage of the phage lytic cycle Bouchard et al. support a late-stage block in the phage lytic cycle.
  • restricted phage propagation confers AbiT system METPO:2007700

    Restriction of 936/P335 phage propagation realizes the AbiT abortive-infection defense trait.

    • DOI:10.1128/JB.184.22.6325-6332.2002 The fact that resistant cells do not survive phage infection proves that the antiphage system carried by pED1 is an Abi mechanism. It was therefore named AbiT. Bouchard et al. define AbiT as a pED1 abortive-infection phage resistance system.
  • AbiT system is a abortive infection system rdfs:subClassOf

    AbiT system possession is an abortive-infection-system trait.

    • DOI:10.1128/JB.184.22.6325-6332.2002 Here, we describe the isolation and characterization of a novel Abi mechanism encoded by plasmid pED1 from L. lactis Bouchard et al. place AbiT in the abortive infection class of phage defense.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1128/JB.184.22.6325-6332.2002

Parent traits (1)

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

  • Lactococcus lactis NCBITaxon:1358 DOI:10.1128/JB.184.22.6325-6332.2002 Bouchard et al. isolated pED1 from Lactococcus lactis W51, localized the AbiT phage-resistance phenotype to abiTi and abiTii, and showed that the determinant restricts 936 and P335 Lactococcus phages after transfer into phage-sensitive Lactococcus lactis strains.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Minted AbiT system as a DOI-backed GENOMICS TraitRecord under the abortive infection system parent after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v107.