TraitMech

TraitMech › PHYSIOLOGY

thigmotropism

traitmech:000594 · CLASS · PROPOSED

A phenotype in which polarized growth is directionally reoriented in response to physical contact with surface topography.

Trait evidence (4)

  • DOI:10.1080/02681219280000621
    The response was likely to be due to contact guidance (thigmotropism) and not chemotropism towards the nutrients

    Abstract, exact-matched at Europe PMC (PMID:1287165); full text not inspected. Candida albicans hyphae entered membrane pores after contacting their lips, including from the underside while growing away from nutrient agar. This supports the authors' contact-guidance interpretation, not exclusion of every chemical influence or proof of tissue invasion in vivo.

  • DOI:10.1099/00221287-144-3-689
    both compounds reduced the percentage of hyphae reorienting on contact with a ridge without markedly affecting hyphal extension rate

    Abstract, exact-matched at Europe PMC (PMID:9534238); full text not inspected. The compounds are GdCl3 and verapamil at the tested low concentrations. Reorientation and extension rate are distinct readouts. Pharmacological attenuation and membrane channel recordings suggest channel involvement but do not identify a unique molecular mechanosensor.

  • DOI:10.1016/j.cub.2006.12.043
    The establishment and maintenance of directional growth in relation to these environmental cues was Ca(2+) dependent.

    Abstract, exact-matched at Europe PMC (PMID:17275302). PMC1885950 full text distinguishes contact-dependent thigmotropism from electric-field galvanotropism. In the reported ridge assays, channel-component mutations reduced reorientation without reducing hyphal extension rates. Calcineurin was required for cathodal emergence but not thigmotropism; do not transfer that pathway requirement between the two responses. Localized channel activation and calcium influx remain a proposed model, not a universal mechanism established in every microbe. Supplement not inspected.

  • DOI:10.1111/cmi.12369
    In vitro, hyphal tips reorient thigmotropically on contact with small obstacles.

    Abstract, exact-matched at Europe PMC (PMID:25262778). PMC4371639 full text, Fig. 6 and supplementary Table S1 were inspected. Adhesion or friction sufficient to oppose forward growth supported acute tip reorientation; less constrained hyphae instead bent subapically. Tip contact alone was insufficient in these assays. Table S1 lists CAI4/CIp10, BWP17 and engineered derivatives, including fluorescent reporters and an rsr1 deletion; the paper's wild-type designation is not proof of natural strain provenance. Spitzenkorper position correlated with growth but was not an absolute predictor. Force magnitudes are not curated because main-text and supplementary Fig. S2 units disagree. Movies were not inspected.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1080/02681219280000621

Parent traits (1)

kg-microbe context

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

Discussions and Knowledge Gaps (2)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Keep contact-directed growth distinct from locomotion and passive bending.

CURATION TODO OPEN thigmotropism-growth-and-contact-boundaries · raised by codex · 2026-10-04

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Polarized growth reorientation is not whole-cell locomotion, so the parent is phenotype, not motile. Filament shape alone does not imply contact sensitivity, and the existing mycelial-growth record is explicitly bacterial. Do not equate this trait with thigmotaxis, stiffness-gradient migration, electric-field growth, generic adhesion or contact-induced differentiation. Passive bending, growth rate changes and incidental alignment alone are insufficient. The fungal observations do not demonstrate a universal mechanosensor or establish tissue invasion in vivo. External equivalences and lexical variants need separate authority and scope checks.

Resolve natural strain provenance and protein-level mechanism evidence.

CURATION TODO OPEN thigmotropism-strain-and-mechanism-grounding · raised by codex · 2026-10-04

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Retain the reported Candida albicans observations as qualified evidence. The inspected strain table includes engineered backgrounds and fluorescent reporters; verify direct measurements in naturally occurring strains and NCBI identities before adding canonical examples. Resolve taxon-paired protein accessions and distinguish channel deletion evidence from inhibitor specificity and proposed localized calcium signals before adding a causal graph. Keep calcineurin's galvanotropic role separate from the reported thigmotropic response. Rsr1-dependent polarity positioning does not make Spitzenkorper position an absolute predictor of growth direction. Inspect remaining full texts and supplements before strengthening these claims; no NONMECHANISTIC graph should bypass missing protein or taxon grounding.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added thigmotropism with four primary DOI citations and exact abstract snippets. Ignored-and-hidden novelty searches and structured OWL review found no exact record or METPO term. Reserved METPO:1054800 in v471. Distinguished contact-directed polarized growth from locomotion and passive bending. Inspected two full texts plus the Thomson Fig. 6 and supplementary strain table. Deferred natural canonical examples and accession-level mechanism grounding; did not infer them from engineered strains.