identifier: traitmech:000609 label: homothallism definition: A fungal phenotype enabling a culture founded from a single spore to reproduce sexually in isolation from a mating partner. definition_source: DOI:10.5598/imafungus.2015.06.01.13 trait_category: PHYSIOLOGY term_kind: CLASS mapping_status: PROPOSED parent_traits: - METPO:1000059 evidence: - reference: DOI:10.5598/imafungus.2015.06.01.13 snippet: the ability of a single spore to produce a sexually reproducing colony when propagated in complete isolation. notes: 2015 terminology review, PMID:26203424. Exact contiguous span of the historical operational definition in the Introduction at https://pmc.ncbi.nlm.nih.gov/articles/PMC4500084/. Abstract, Introduction and Conclusions were read as full-text XML; mechanism-specific sections and figures remain uninspected. This is definition authority, not experimental replication. Homothallism is an umbrella encompassing primary homothallism, pseudohomothallism, mating-type switching and unisexual reproduction, not one universal MAT architecture. The snippet is full text, not an abstract quote. - reference: DOI:10.1371/journal.pgen.1006981 snippet: The filamentous fungus Chromocrea spinulosa (Trichoderma spinulosum) exhibits both self-fertile (homothallic) and self-sterile (heterothallic) sexual reproductive behavior. notes: Yun et al. (2017), PMID:28892488. Exact sentence of the directly retrieved Europe PMC scientific abstract, separate from the author summary. Strain/culture Methods and Conclusions were read at PMC5608430; most main-text experiments, actual figures and supplements remain uninspected. Cs23 and Cs27 are the paper's self-fertile and self-sterile reference strains; their original natural provenance has not been verified. MAT manipulation supports direct-repeat-mediated MAT1-2 loss and recognition between unlike nuclei in a shared cytoplasm. Both intact MAT1-1-1 and MAT1-2-1 in one nucleus are not sufficient for self-fertility. The authors describe a heterothallic strategy at the nuclear level, not primary homothallism, while retaining organism-level self-fertility. Unstable Cs27 transformants were tested directly from transformation plates; do not generalize their stability. - reference: DOI:10.7554/elife.79114 snippet: Our findings support C. depauperatus as an obligately sexual, homothallic fungus notes: Passer, Clancey et al. (2022), PMID:35713948. Exact independent clause of the scientific abstract in PMC9296135 full-text XML. Europe PMC's abstractText instead returns the eLife digest; a manual scientific-abstract match is not a VERIFIED resolver verdict. Publisher version 2 assets were retrieved through https://api.elifesciences.org/articles/79114. Introduction, strain/culture Methods, deletion-mutant Results and intra-/interstrain crossing and recombination Results were read. Actual Figures 5 and 8 and their captions were inspected; Supplementary file 1 strain rows were read from the publisher's elife-79114-supp1-v2.xlsx. Other figures, supplements and unread Methods remain uninspected. Figure 5 separates wild-type CBS7841 sporulation from pheromone/receptor and DMC1 deletion phenotypes. Hyphal growth alone does not establish meiosis. Figure 8 recombination assays use CBS7841-derived marker strains, including UV-induced and spontaneous mutants, not the unmodified canonical isolate. Drug resistance alone is not evidence of sex; genotyping distinguishes recombination from new mutations. Tested interstrain crosses did not yield PCR-confirmed recombinant progeny, so universal compatibility is not asserted. Obligately sexual describes this source's example, not a requirement for all homothallic fungi. canonical_examples: - taxon_id: NCBITaxon:1295531 taxon_label: Cryptococcus depauperatus CBS 7841 reference: DOI:10.7554/elife.79114 note: 'Qualified natural-isolate example: wild-type CBS7841, distinguished from its laboratory derivatives in Supplementary file 1. Figure 5A shows basidia and spore chains after one week on V8 medium at room temperature in the dark; Figure 5B assays sporulation after ten days on Murashige-Skoog medium. The paper''s composite sexual-cycle evidence includes separate mutant experiments, not all measurements on wild type. Natural provenance is independently documented by https://www.atcc.org/products/36983: B3810 [CBS 7841, TRTC 48044], isolated from a dead spider in Ontario, Canada. This collection record supports provenance, not independent trait replication. NCBI taxonomy 1295531 resolves to this active strain name on 2026-10-04.' discussions: - discussion_id: homothallism-trait-scope prompt: Preserve organism-level self-fertility across distinct mating mechanisms. kind: CURATION_TODO status: OPEN rationale: This is a reproductive phenotype, not a sequence feature or MAT-gene inventory. The operational single-spore definition does not require a uninucleate spore, both MAT idiomorphs in one nucleus, or one molecular mechanism. It does not exclude outcrossing or require universal compatibility, obligate sexuality, or self-fertility of every progeny. Distinguish self-fertility from asexual cloning, ploidy, heterokaryosis, hyphal fusion and parasexual reproduction; these are not is-a parents. PHYSIOLOGY is a filesystem category, not an ontology parent. Self-fertility and self-compatibility also have uses outside fungi; resolve their lexical scope and external phenotype/process mappings before adding synonyms or xrefs. posed_by: codex posed_date: '2026-10-04' - discussion_id: homothallism-mechanism-and-readouts prompt: Resolve native proteins and sexual-cycle readouts before adding causal edges. kind: CURATION_TODO status: OPEN rationale: Complete unread experiments and supplements before expanding mechanistic claims. Separate wild-type sporulation, deletion phenotypes, marker segregation and inter-marker recombination. MAT homology or expression alone cannot establish a sexual cycle, and neither independent chromosome assortment nor drug resistance alone excludes parasexual processes. Resolve native protein accessions, experimental dependencies and taxonomic provenance before adding a mechanistic graph; do not use NONMECHANISTIC to bypass unresolved grounding. Retain the actual abstract-verifier outcome when an API returns an editorial digest, and identify manual full-text checks separately. posed_by: codex posed_date: '2026-10-04' curation_history: - timestamp: '2026-10-05T01:23:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Added homothallism with a definition review and two primary DOI-backed studies, each with an exact source snippet. Separated self-fertility from mating-locus content and retained strain and assay qualifiers. Added natural CBS 7841 after primary figure, strain-table, ATCC provenance and NCBI identity checks. Ignored-and-hidden novelty searches and structured METPO review found no exact record. Reserved METPO:1056300 in v486 under released phenotype. Deferred lexical mappings and protein-resolved graphs. llm_assisted: true