TraitMech

TraitMech › ECOLOGY

commensalism

traitmech:000042 · CLASS · REVIEWED

A symbiosis in which the microorganism benefits from the association (e.g. resources, shelter, transport) while the host's fitness remains essentially unaffected.

Commensalism benefits microbe without affecting host fitness

Evidence-backed causal sketch linking host colonization to microbial benefit while host fitness is essentially neutral.

Commensalism benefits microbe without affecting host fitness Interactive directed graph showing evidence-backed causal relationships for commensalism.

Edge evidence

  • host colonization enables commensalism RO:0002327

    Persistent colonization without harm or benefit to the host realizes the commensal lifestyle.

    • DOI:10.1073/pnas.1218525110 McFall-Ngai et al. support commensal colonization as a major class of host-associated microbial lifestyles.
  • commensalism associated with neutral host fitness effect biolink:associated_with

    Commensal interactions sit on the near-neutral point of the parasite-mutualist continuum.

    • DOI:10.1038/s41579-021-00550-7 Drew et al. place commensalism on the parasite-mutualist continuum as a near-neutral host interaction.
  • secretory IgA promotes host colonization RO:0002213

    Secretory IgA can help commensal bacteria colonize the mucus layer.

    • DOI:10.1126/science.adi3338 IgA can act as a carrot as well as a stick, helping bacteria colonize the mucus layer.
  • host mucus / mucins provides resources for host colonization

    Host mucin glycans provide niche and nutrients enabling commensal persistence.

    • DOI:10.1126/science.adi3338 Mucin glycan availability selectively feeds mucin-degrading taxa, providing a host-derived resource.
  • bacterial glycan-binding proteins enables attachment to mucin RO:0002327

    Bacterial glycan-binding proteins mediate attachment to host mucin.

    • DOI:10.1126/science.adi3338 Bacteria attach to mucin via glycan-binding proteins.
  • attachment to mucin enables host colonization RO:0002327

    Attachment to the mucin layer supports persistent host colonization.

    • DOI:10.1126/science.adi3338 Attachment to mucin via glycan-binding proteins underlies persistent colonization of the mucus niche.
  • extracellular glucan / EPS production produces EPS biofilm matrix METPO:2000202

    Synthesis of extracellular glucans builds the EPS biofilm matrix.

    • DOI:10.3389/fcimb.2024.1357631 Synthesis of extracellular glucans builds the EPS biofilm matrix.
  • EPS biofilm matrix confers protection from shear and antimicrobials

    The EPS biofilm matrix protects cells from shear forces and antimicrobials.

    • DOI:10.3389/fcimb.2024.1357631 Protects cells from shear forces and confers resistance to antimicrobials.
  • protection from shear and antimicrobials promotes host colonization RO:0002213

    Protection from removal and antimicrobials supports persistence in the host niche.

    • DOI:10.3389/fcimb.2024.1357631 Biofilm-conferred resistance supports persistence in a host niche.
  • low virulence / no detectable host cost operationalizes commensalism

    Benefit to the microbe with no detectable host cost operationalizes commensalism.

    • DOI:10.1038/s41579-021-00550-7 Commensals benefit from the interaction with hosts but do not cause a detectable cost.

Knowledge gaps & discussions (1)

KNOWLEDGE_GAP OPEN Knowledge gap for commensalism: MicroRNAs (miRNAs) are small, noncoding RNAs involved in posttranscriptional gene regulation in both animal and plant. miRNAs derived from edible plants, referred to as xenomiRs, are proposed to cross-kingdom barriers and to modulate mammalian gene expression.

Surfaced by the Europe PMC literature gap-signal scan (categories: controversy_conflict, explicit_gap, future_work, limitations_barriers, unclear_unknown). Curator review required: set attaches_to, refine the prompt, and weigh the cited evidence.

4 evidence item(s)
NO_EVIDENCE PMID:40945860 MicroRNAs (miRNAs) are small, noncoding RNAs involved in posttranscriptional gene regulation in both animal and plant. miRNAs derived from edible plants, referred to as xenomiRs, are proposed to cross-kingdom barriers and to modulate mammalian gene expression. Gap-signal sentence (limitations_barriers) from the cited abstract.
NO_EVIDENCE PMID:40574831 Emerging evidence suggests the gut microbiota plays a role in immune regulation, yet its impact on ITP remains unclear. Gap-signal sentence (unclear_unknown) from the cited abstract.
NO_EVIDENCE PMID:42197356 Examining the existing literature may identify knowledge gaps regarding precise mechanisms through which the development of GM influences the maturation of the immune system. Gap-signal sentence (explicit_gap) from the cited abstract.
NO_EVIDENCE PMID:41808832 Given its promising anti-inflammatory properties, further research is warranted. Gap-signal sentence (future_work) from the cited abstract.

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1038/s41579-021-00550-7

Parent traits (1)

Synonyms (1)

  • commensal RELATED_SYNONYM · DOI:10.1038/s41579-021-00550-7

kg-microbe context

Matched 1 kg-microbe node via parent_proxy.

  • METPO:1000059 [-2.682, -2.070, -3.656, -0.652, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Curation history

  1. · PROPOSED_FROM_RESEARCH · claude

    Proposed candidate ECOLOGY trait (commensalism); sub-variant of symbiosis.

  2. · CURATED_CAUSAL_GRAPH · claude

    Added evidence-backed causal graph (commensalism / neutral host fitness) with RO/biolink predicate groundings; promoted PROPOSED to REVIEWED.

  3. · ENRICH_CAUSAL_GRAPH · claude

    Added 8 evidence-backed generic edges (8 new nodes) from the deep-research report.

  4. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 5 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (RO:0002213×2, RO:0002327×2, METPO:2000202×1).