identifier: traitmech:000009 label: UV radiation tolerant definition: An environmental tolerance in which an organism survives high doses of ultraviolet radiation, typically via photoreactivation and nucleotide-excision repair of cyclobutane pyrimidine dimers and 6-4 photoproducts. definition_source: DOI:10.3390/genes14091803 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - traitmech:000007 synonyms: - synonym_text: UV resistant synonym_type: RELATED_SYNONYM source: DOI:10.3390/genes14091803 evidence: - reference: DOI:10.3390/genes14091803 snippet: Deinococcus radiodurans R1 demonstrates a significantly higher radiation resistance with D10 values exceeding 12 kGy for gamma radiation and 700 J/m2 for UV-C radiation notes: 'Organism example: Deinococcus radiodurans tolerates UV-C radiation D10 doses of 700 J/m2.' - reference: DOI:10.1101/cshperspect.a012765 snippet: The bacterium Deinococcus radiodurans is a champion of extreme radiation resistance notes: Review support — Deinococcus radiodurans is the reference organism for extreme UV and ionizing radiation resistance. canonical_examples: - taxon_id: NCBITaxon:1299 taxon_label: Deinococcus radiodurans note: "UV-resistant" reference: PMID:11238985 - taxon_id: NCBITaxon:54298 taxon_label: Chroococcidiopsis note: "desert UV-tolerant cyanobacterium" reference: PMID:23239185 causal_graphs: - graph_id: uv_tolerance_excision_repair title: UV-radiation tolerance via nucleotide-excision and photoreactivation repair description: Evidence-backed causal sketch linking UV-induced pyrimidine dimers to nucleotide-excision and photoreactivation repair. nodes: - node_id: uv_tolerant_trait label: UV radiation tolerant node_type: TRAIT grounding: traitmech:000009 description: Survival of high doses of UV radiation. - node_id: uv_radiation label: ultraviolet radiation node_type: ENVIRONMENTAL_FACTOR description: Solar / UV-C exposure inducing pyrimidine dimers and 6-4 photoproducts. grounding: ENVO:21001216 - node_id: nucleotide_excision_repair label: nucleotide-excision repair node_type: BIOLOGICAL_PROCESS grounding: GO:0006289 description: Removal and replacement of UV-damaged DNA segments. - node_id: photoreactivation label: photoreactivation node_type: BIOLOGICAL_PROCESS description: Photolyase-mediated reversal of pyrimidine dimers. - node_id: cyclobutane_pyrimidine_dimer label: cyclobutane pyrimidine dimer node_type: CHEMICAL description: Major UV-induced DNA photoproduct (CPD) joining adjacent pyrimidines. - node_id: pyrimidine_6_4_photoproduct label: pyrimidine (6-4) pyrimidone photoproduct node_type: CHEMICAL description: Second principal UV-induced DNA lesion (6-4PP). - node_id: cpd_photolyase label: CPD photolyase node_type: GENE_OR_PROTEIN description: Light-driven enzyme that directly reverses cyclobutane pyrimidine dimers. - node_id: catalase label: catalase node_type: GENE_OR_PROTEIN description: Antioxidant enzyme detoxifying reactive oxygen species generated by UV. grounding: UniProtKB:A0A071MK53 - node_id: reactive_oxygen_species label: reactive oxygen species node_type: CHEMICAL description: ROS produced under UV exposure causing oxidative damage. grounding: CHEBI:26523 - node_id: mycosporine_like_amino_acids label: mycosporine-like amino acids node_type: CHEMICAL description: UV-screening metabolites that absorb UV-A/UV-B and dissipate it as heat. grounding: CHEBI:35738 edges: - subject: uv_radiation predicate: challenges object: uv_tolerant_trait description: UV exposure is the environmental challenge the trait counters. evidence: - reference: DOI:10.3390/genes14091803 notes: Deinococcus radiodurans tolerates UV-C D10 doses of 700 J/m2. predicate_id: METPO:2007406 - subject: nucleotide_excision_repair predicate: enables object: uv_tolerant_trait description: NER removes UV-induced cyclobutane pyrimidine dimers and 6-4 photoproducts. evidence: - reference: DOI:10.3390/genes14091803 notes: D. radiodurans tolerates lethal UV-C doses via excision-based repair of UV photoproducts. predicate_id: RO:0002327 - subject: photoreactivation predicate: enables object: uv_tolerant_trait description: Photolyase-mediated dimer reversal complements excision repair. evidence: - reference: DOI:10.1101/cshperspect.a012765 notes: D. radiodurans is the reference organism for extreme UV and ionizing radiation resistance. predicate_id: RO:0002327 - subject: uv_radiation predicate: causes object: cyclobutane_pyrimidine_dimer description: UV exposure produces cyclobutane pyrimidine dimers, the majority DNA lesion. evidence: - reference: DOI:10.3390/life14070822 notes: 'UV produces two primary pyrimidine photoproducts: CPDs (majority lesion) and 6-4PPs; central trait-defining lesion, general across taxa.' predicate_id: biolink:causes - subject: uv_radiation predicate: causes object: pyrimidine_6_4_photoproduct description: UV exposure produces pyrimidine (6-4) pyrimidone photoproducts. evidence: - reference: DOI:10.3390/life14070822 notes: Principal UV lesions include CPDs and pyrimidine (6-4) pyrimidone photoproducts; strong and general. predicate_id: biolink:causes - subject: cpd_photolyase predicate: repairs object: cyclobutane_pyrimidine_dimer description: CPD photolyase directly reverses cyclobutane pyrimidine dimers via light-driven electron transfer. evidence: - reference: DOI:10.3390/ijms241512381 notes: Photolyases directly reverse UV photoproducts; CPD photolyase uses light-driven electron transfer to monomerize CPD dimers; canonical general edge. - subject: catalase predicate: detoxifies object: reactive_oxygen_species description: Catalase scavenges UV-induced reactive oxygen species, preventing oxidative damage. evidence: - reference: DOI:10.3390/microorganisms13040756 notes: Genomic analyses implicate catalases in UV resistance; ROS-scavengers/catalases detoxify ROS and prevent oxidative damage; general antioxidant edge. - subject: mycosporine_like_amino_acids predicate: absorbs object: uv_radiation description: MAAs absorb UV-A/UV-B (~309-362 nm) and release it as harmless heat, screening UV. evidence: - reference: DOI:10.3390/ijms241512381 notes: MAAs absorb ~309-362 nm with high extinction coefficients and release absorbed UV as harmless heat; strong, general for cyanobacteria/algae. - subject: mycosporine_like_amino_acids predicate: quenches object: reactive_oxygen_species description: MAAs act as antioxidants that quench UV-induced reactive oxygen species. evidence: - reference: DOI:10.3390/ijms241512381 notes: MAAs act as antioxidants/free-radical scavengers and quench ROS induced by PAR, UV-A, and UV-B; strong, mechanism/class-level. curation_history: - timestamp: '2026-05-28T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate ENVIRONMENT trait (ultraviolet radiation tolerance) from literature research; sub-variant of radiotolerant. llm_assisted: true - timestamp: '2026-06-09T14:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (NER + photoreactivation) with GO node grounding and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-14T06:55:38Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (ENVO:21001216×1). llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 6 evidence-backed generic edges (6 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:11Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 2 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (biolink:causes×2). llm_assisted: true - timestamp: '2026-06-24T17:21:18Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:A0A071MK53×1). llm_assisted: true - timestamp: '2026-06-24T17:23:32Z' curator: claude action: GROUND_CAUSAL_NODES changes: Grounded 2 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:26523×1, CHEBI:35738×1). llm_assisted: true