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positive autotropism

traitmech:000604 · CLASS · PROPOSED

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

Trait evidence (2)

  • DOI:10.1093/jxb/19.1.125
    the positive germ-tube, i.e. one beginning more nearly towards its neighbour

    Robinson, Park and Graham (1968), original publisher abstract directly retrieved from https://oup.silverchair-cdn.com/article-minimal/447341. The abstract reports positive autotropism in Botrytis cinerea on Cellophane over agar and neutrality on agar alone. The quoted orientation definition occurs in the mixed-orientation spore-pair timing comparison for Rhizopus stolonifer and Mucor plumbeus, both described as exhibiting marked negative autotropism. Earlier emergence of the positive germ-tube in those pairs does not establish a net positive response in either species. The abstract defines positive germ-tube orientation relative to the neighboring spore. This supports the terminology and emergence component, not later tip bending or completed fusion. Germination timing and cis-ness are separate readouts. The full paper, strain provenance and sample sizes were not retrieved. No universal chemical mechanism is inferred from the abstract's proposed explanations.

  • DOI:10.1039/d3lc00859b
    The hyphae approach each other from opposing directions with occasional arrestation of growth and readjustment of the growth direction.

    Richter et al. (2024), Results section on stop-and-go growth before anastomosis; directly retrieved Europe PMC full-text JATS, PMC10964749 (PMID:38416560). Culture and image-analysis methods, corresponding Discussion and actual Figure 5 were inspected. Figure 5a-c shows Rhizophagus irregularis MUCL 43194 approaching before fusion; the 21-hour trace is a representative pair, not a replication count. This is independent extension evidence interpreted within the directional definition, not an assertion that this paper uses the autotropism label. Supplementary methods and movies were not retrieved; attachment requests returned access-check HTML or HTTP errors.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1093/jxb/19.1.125

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.

Retain the distinction between directional approach and fusion.

CURATION TODO OPEN positive-autotropism-direction-and-fusion-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.

Initial germ-tube orientation and later hyphal redirection are distinct readouts; the definition does not require both in one organism. Hyphal fusion/anastomosis is a separate endpoint, not an exact synonym or a prerequisite. Same-species neighbors can include branches of one mycelium or separate spores; genetic identity is not required by this definition. Do not infer whole-cell taxis, chemotropism, mating or a particular self-recognition mechanism. Passive alignment, faster growth and contact alone are insufficient. Negative autotropism has the opposite direction, not the same phenotype. Resolve external equivalences before adding xrefs or synonyms.

Verify strain origins, supplements and native signaling mechanisms.

CURATION TODO OPEN positive-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 await original strain-provenance and NCBI identity checks. The 2024 culture method uses transformed chicory roots; this does not establish engineering of the fungi. Inspect the original supplements and the 1968 full paper before quantitative or strain-level enrichment. No universal ligand/receptor chain is established by these observations. A causal graph requires directly supported native perturbations and taxon-paired protein accessions; NONMECHANISTIC is not a grounding bypass.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added positive autotropism with two directly retrieved DOI-backed sources and exact snippets. Distinguished orientation and extension from completed fusion. Ignored-and-hidden searches and structured OWL review found no exact term; the negative sibling's boundary mention is not a duplicate. Reserved METPO:1055800 in v481 under released phenotype. Inspected Figure 5 and retained abstract-only, representative-pair and unread-supplement limitations. Deferred canonical strains, synonyms, external equivalents and causal graphs.

  2. · REFINE_EVIDENCE_SNIPPET · codex

    Addressed #1687 by replacing the anaphoric label-only 1968 quote with its exact germ-tube orientation definition. Qualified the mixed-orientation timing comparison without inferring net positive autotropism in its two negative-response species. Retained the separate Botrytis cinerea substrate-dependent observation.