identifier: traitmech:000658 label: fungal chlamydospore formation definition: A morphological phenotype in which a fungus forms enlarged, thick-walled cells called chlamydospores. definition_source: DOI:10.1038/s41467-020-20010-9 trait_category: MORPHOLOGY term_kind: CLASS mapping_status: PROPOSED parent_traits: - METPO:1000059 evidence: - reference: DOI:10.1038/s41467-020-20010-9 snippet: Chlamydospores are enlarged thick-walled cells produced within hyphae or at hyphal tips notes: Hernandez-Cervantes et al. (2020), PMID:33277479, PMC7718266, Introduction; this contiguous clause supplies morphological terminology, not independent experimental replication across all fungi. Abstract, Introduction and selected Methods were read directly. Mechanistic panels and supplementary strain tables were not inspected, so no universal Rme1 dependence or protein-resolved causal graph is asserted. The definition does not impose a survival function. - reference: DOI:10.1099/13500872-141-7-1507 snippet: These organisms were germ-tube-positive and produced abundant chlamydospores which were frequently arranged in triplets or in contiguous pairs. notes: Sullivan et al. (1995), PMID:7551019, original Candida dubliniensis description; scientific abstract retrieved directly from Europe PMC. These organisms refers to the recovered oral clinical isolates. This is primary phenotype and natural-isolate provenance at cohort level, not evidence that chlamydospores were observed in patient tissue. Full Methods and strain tables were not inspected; no named culture, universal arrangement or response of every strain is inferred. - reference: DOI:10.3389/fmicb.2016.01697 snippet: Both species produced typically high amounts of chlamydospores on rice and CM agar (chlamydospore index [CI] 3). notes: Bottcher et al. (2016), PMID:27833594, PMC5081361, Figure 1 caption. Actual Figure 1 micrographs, Methods and Tables 1-2 were inspected. The strains are C. albicans SC5314 and C. dubliniensis Wu284, rendered with an umlaut in the source; CM means corn meal. Cultures were examined after seven days at 27 C in darkness. CI is an ordinal 0-3 score, not a cell percentage. Nutrient effects differ by strain and medium; no universal starvation or darkness requirement is inferred. Independent provenance of these laboratory strains was not checked, so they are not the canonical example. - reference: DOI:10.1111/j.1567-1364.2009.00533.x snippet: Mycelium-attached and purified chlamydospores rapidly lost their viability in water and when subjected to dry stress notes: Citiulo et al. (2009), PMID:19538507, scientific abstract retrieved directly from Europe PMC and checked against publisher text. The complete result clause is quoted before the authors' interpretation about long-term storage. It argues against assuming durable dormancy for these Candida cells, not against survival roles in every fungus. The publisher Introduction and selected Methods were also read; the Introduction calls Candida budding blastic conidiogenesis and explains chlamydoconidia terminology. Formation is kept separate from subsequent germination and viability. - reference: https://research.fs.usda.gov/treesearch/30277 snippet: Cell walls of mature P. ramorum chlamydospores are thicker than reported for other Phytophthora species, although thin-walled chlamydospores are also formed. notes: 'Smith and Hansen (2008), USDA proceedings report, pp. 451-454; directly retrieved repository abstract. The repository labels it Informally Refereed. NCBI Taxonomy confirms Phytophthora ramorum is an oomycete in Stramenopiles, not Fungi. This is terminology-boundary evidence, not a fungal observation: the fungal qualifier avoids silently including the report''s thin-walled structures in a thick-walled fungal definition. Full report and figures were not inspected; no canonical oomycete or universal wall-thickness cutoff is asserted.' - reference: DOI:10.1007/s10886-012-0171-1 snippet: two species of Fusarium formed chlamydospores from hyphae, germ tubes, or inside the conidia within 2 days. notes: Li et al. (2012), PMID:22932866, scientific abstract retrieved directly from Europe PMC. This result concerns sub-MIC FA17 fengycin treatment of two Fusarium species, not untreated formation in every fungus. It establishes a conidial route excluded by the initial hypha-only draft definition (#1772). The abstract separately calls structures in 17 other fungi chlamydospore-like; those are not promoted to equivalent phenotypes. Full Methods, figures and strain provenance were not inspected, so no additional canonical strain or causal chemical mapping is asserted. canonical_examples: - taxon_id: NCBITaxon:42374 taxon_label: Candida dubliniensis reference: DOI:10.1099/13500872-141-7-1507 note: Species-level example from naturally recovered oral clinical isolates in the original 1995 description. The primary scientific abstract at https://doi.org/10.1099/13500872-141-7-1507 reports abundant chlamydospore production. This supports cohort-level isolate provenance, not a particular named laboratory culture, an inferred wild-type or GMO status, or chlamydospores in patient tissue. Full strain tables and Methods were not inspected; the observation is not assigned to CD36 or to every strain or condition. discussions: - discussion_id: fungal-chlamydospore-scope-and-hierarchy prompt: Resolve conidiation, dormancy and process-ontology mappings. kind: CURATION_TODO status: OPEN rationale: 'Retain phenotype METPO:1000059. Sporulation METPO:1000870 and spore forming METPO:1000871 explicitly concern endospores. Citiulo et al. (2009) call Candida chlamydospore budding blastic conidiogenesis; that source-attributed usage does not settle whether this broader fungal class should be below fungal conidiation traitmech:000657. Do not equate it with ordinary pseudohyphal growth or any hyphal swelling. Closed upstream issue https://github.com/berkeleybop/metpo/issues/67 suggested chlamydospores under resting spores; the Candida viability evidence does not support that as a universal function. GO:0001410 was resolved through QuickGO: it is a biological process and its survival/endogenous-formation wording also needs scope review. Leave exact synonyms and xrefs unset rather than asserting equivalence. The four obsolete METPO chlamydospore terms are material classes, not active organismal phenotypes.' posed_by: codex posed_date: '2026-10-07' - discussion_id: fungal-chlamydospore-function-and-mechanism prompt: Separate morphological identification from survival and regulation. kind: KNOWLEDGE_GAP status: OPEN rationale: 'Wall thickening alone does not establish long-term survival, dormancy, infectivity or a dispersal function. Preserve species-, strain-, age- and medium-specific endpoints. Do not require one arrangement, nucleus count, nutrient trigger or illumination regime. The USDA Phytophthora report documents a nonfungal terminology boundary, not additional fungal replication. Formation and later germination are different observations. A causal graph is deferred pending reconciliation of primary perturbations and supplementary strain identities with natural-host provenance and taxon-paired protein accessions. Gene possession alone is not a chlamydospore phenotype. Li et al. (2012), PMID:22932866, report formation inside conidia as well as from hyphae and germ tubes under the tested treatment. Issue #1772 corrected the initial hypha-only restriction; retain formation-site neutrality and do not promote the separately reported chlamydospore-like structures to confirmed chlamydospores.' posed_by: codex posed_date: '2026-10-07' curation_history: - timestamp: '2026-10-07T04:23:14Z' curator: codex action: MINTED_TRAITMECH_ID changes: Added fungal chlamydospore formation with five directly checked snippets, a cohort-qualified Candida dubliniensis example and explicit terminology, hierarchy and function limits. Ignored-and-hidden searches found no exact live record. Reserved METPO:1061100 in v534; existing records unchanged and causal graph deferred. llm_assisted: true - timestamp: '2026-10-07T04:34:28Z' curator: codex action: REVISED_DEFINITION changes: 'Addressed #1772: removed the hypha-only formation-site restriction, added the primary Fusarium conidial-route counterexample and retained treatment and source-access limits. Preserve the initial curation event and canonical example.' llm_assisted: true