negative autotropism

traitmech:000603 · CLASS · PROPOSED

A phenotype in which germ-tube emergence or hyphal extension is directionally biased away from neighboring cells or hyphae of the same species.

Trait evidence (2)

DOI:10.3390/biomimetics10050287
the hyphae often diverted their growth from their initial direction away from each other.

Montiel-Rubies et al. (2025), Section 3.4.1; exact span in directly retrieved Europe PMC JATS, PMC12109565 (PMID:40422117). Methods and Sections 3.2/3.4.1 were read; Figure 5 and Table 2 were visually inspected in the authors' PDF. This is a retrospective analysis of earlier microfluidic experiments, not a new independent replication of those datasets. Side-by-side Pycnoporus cinnabarinus hyphae redirected laterally where space allowed. Figure 5B instead shows head-on arrest and cytoplasm retreat, not growth away. Armillaria mellea divergence could reflect directional memory. For Neurospora crassa, Table 2 rates side-by-side avoidance strong and head-on avoidance not observed; prose calls the latter extremely rare. These qualitative descriptions are not counts or replication estimates. Supplementary movies were not inspected. The definition uses the directional-growth component of this paper's broader usage.
DOI:10.1093/jxb/19.1.125
When germinated on agar surfaces the first three species exhibited negative autotropism, B. cinerea being neutral in its autotropic behaviour.

Robinson, Park and Graham (1968), original publisher abstract directly retrieved from https://oup.silverchair-cdn.com/article-minimal/447341. The first three species are Rhizopus stolonifer, Mucor plumbeus and Trichoderma viride. Spore-pair assays concern orientation of germ-tube emergence, not demonstrated subsequent tip bending. Cellophane increased their negative response; Botrytis cinerea was neutral on agar and positive on Cellophane, so is not a negative exemplar here. Germination timing and cis-ness are separate readouts, not substitutes for orientation. The full paper, figures, strain provenance and sample sizes were not retrieved; proposed mechanisms in the abstract are not established causal pathways.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.3390/biomimetics10050287

Parent traits (1)

phenotype METPO:1000059

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.

Retain directional growth and stage-specific self-avoidance boundaries.

CURATION TODO OPEN negative-autotropism-direction-and-self-scope · 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.

The directional phenotype includes initial germ-tube orientation and later hyphal redirection without requiring both in one organism. Same-species neighbors can include branches of one mycelium or separate spores; this does not assert genetic identity, vegetative incompatibility or a self-recognition receptor. Positive autotropism and hyphal fusion are not exact synonyms. Whole-cell taxis, growth inhibition, branching, passive bending and cytoplasm retreat alone are insufficient. The 2025 head-on category is broader than this record's directional scope. Do not infer chemotropism or aerotropism parentage from proposed inhibitory cues or oxygen depletion. Resolve external equivalents before adding xrefs or synonyms.

Resolve natural strain provenance and causal signals before enrichment.

CURATION TODO OPEN negative-autotropism-provenance-and-mechanism · 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.

Canonical examples are deferred until the original strain sources and NCBI identities are verified. The 1968 full paper remains unread; the 2025 Methods refer strain culture details to earlier studies and include a ro-1 mutant whose origin has not been verified here. Mutation alone does not establish genetic engineering or natural provenance. Inspect the original imaging datasets and movies before quantitative prevalence claims. Spatial constraints, directional memory and local resource gradients remain competing contributors. Neither paper establishes a universal signal/receptor chain. Resolve direct native perturbation evidence and taxon-paired protein accessions before a causal graph; NONMECHANISTIC is not a grounding bypass.

Curation history

2026-10-04T20:13:46Z · MINTED_TRAITMECH_ID · codex
Added negative autotropism with two directly retrieved DOI-backed sources and exact snippets. Distinguished germ-tube emergence from hyphal redirection and excluded head-on arrest/retreat alone. Ignored-and-hidden searches and structured OWL review found no exact term. Reserved METPO:1055700 in v480 under released phenotype. Inspected Figure 5 and Table 2; retained retrospective-data, qualitative-assay and abstract-only limitations. Deferred canonical strains, external equivalents and molecular mechanisms.
2026-10-04T20:20:10Z · QUALIFY_STRAIN_PROVENANCE · codex
Issue #1684: removed the unsupported engineered qualifier for ro-1. The directly read source identifies a mutant but does not establish its origin; neither engineering nor natural provenance is inferred from mutation alone. Original mint history is preserved.