| Evidence type | Key findings | Species/system | Strength for annotating A0A314KPU1 | Citation ID | Publication year | URL |
|---|---|---|---|---|---|---|
| Biochemical reaction | Plant CuAOs catalyze oxidative deamination/terminal oxidation of polyamines, yielding aminoaldehydes plus H2O2 and NH3; CuAO proteins are copper/TPQ-dependent amine oxidases. | Arabidopsis thaliana CuAOs; plant CuAO family | Indirect-family inference | (pqac-00000001, pqac-00000005, pqac-00000008) | 2013, 2023 | https://doi.org/10.1186/1471-2229-13-109 ; https://doi.org/10.3389/fpls.2023.1154431 |
| Substrate specificity | Recombinant Arabidopsis AtCuAO1/2/3 oxidized putrescine and spermidine, but not spermine in the cited assays; reviews note putrescine is often the preferred substrate and spermine is poorer. | Arabidopsis thaliana | Indirect-family inference | (pqac-00000003, pqac-00000005, pqac-00000009) | 2013, 2023 | https://doi.org/10.1186/1471-2229-13-109 ; https://doi.org/10.1093/jxb/erac411 |
| Family/domain support | CuAOs are homodimeric copper/topaquinone enzymes containing conserved copper-binding histidines, a Tyr-derived TPQ cofactor, and an essential Asp active-site residue; this matches the UniProt family assignment for A0A314KPU1. | Plant CuAO family | Indirect-family inference | (pqac-00000001, pqac-00000005) | 2013 | https://doi.org/10.1186/1471-2229-13-109 |
| Localization | Plant CuAOs localize to distinct compartments, especially apoplast/extracellular space and peroxisomes; AtCuAO1 is extracellular, AtCuAO2/3 are peroxisomal. Tobacco localization methods paper also discusses peroxisomal localization of tobacco CuAOs/MPO. | Arabidopsis thaliana; tobacco transient-expression systems | Indirect-family inference | (pqac-00000000, pqac-00000002, pqac-00000006) | 2013, 2018 | https://doi.org/10.1186/1471-2229-13-109 ; https://doi.org/10.1007/978-1-4939-7398-9_20 |
| Regulation | CuAO genes respond to ABA, methyl jasmonate, salicylic acid, flagellin22, and wounding; recent family-wide synthesis also notes induction by MeJA, ABA, and SA. | Arabidopsis thaliana; plant CuAO family | Indirect-family inference | (pqac-00000001, pqac-00000003, pqac-00000007) | 2013, 2025 | https://doi.org/10.1186/1471-2229-13-109 ; https://doi.org/10.3389/fpls.2025.1544527 |
| Physiological role | CuAO-generated H2O2 contributes to stress signaling, including stomatal closure, systemic wound responses, and protoxylem differentiation; apoplastic AtCuAOβ is a key ROS source in guard-cell/wound signaling. | Arabidopsis thaliana | Indirect-family inference | (pqac-00000008, pqac-00000012, pqac-00000013) | 2023 | https://doi.org/10.3389/fpls.2023.1154431 |
| ROS/defense context | CuAOs are positioned in plant defense-associated ROS networks, producing sustained H2O2 in apoplast/peroxisomes and contributing to defense/stress signaling. | Arabidopsis and general plant defense context | Indirect-family inference | (pqac-00000009, pqac-00000010, pqac-00000011) | 2023, 2025 | https://doi.org/10.1093/jxb/erac411 ; https://doi.org/10.3389/fpls.2025.1544527 |
| Nicotiana nicotine-pathway MPO context | In Nicotiana attenuata nicotine-pathway context, MPO oxidizes N-methylputrescine to N-methylaminobutyric acid/N-methylaminobutanal en route to the pyrrolinium intermediate; nicotine-pathway genes are predominantly root-specific. | Nicotiana attenuata; Nicotiana pathway literature | Indirect-Nicotiana MPO pathway | (pqac-00000017, pqac-00000018, pqac-00000020) | 2025, 2017 | https://doi.org/10.3389/fpls.2025.1647622 ; https://doi.org/10.4225/03/58b77d49bebeb |
| Nicotiana regulation context | Nicotiana nicotine biosynthesis is upregulated by insect feeding/wounding and jasmonate signaling; MPO is listed among structural genes induced by wound stress and MeJA in Nicotiana pathway literature. | Nicotiana attenuata and Nicotiana spp. | Indirect-Nicotiana MPO pathway | (pqac-00000018, pqac-00000019, pqac-00000021) | 2025, 2017 | https://doi.org/10.3389/fpls.2025.1647622 ; https://doi.org/10.4225/03/58b77d49bebeb |
| Quantitative data | Arabidopsis wound-response study: local stomata began closing within 5 min and reached ~75% peak closure at 1 h; distal stomata began closing after 30 min and reached ~70% peak closure between 1 and 24 h; assays used n=15 biological replicates and >=60 stomata per leaf. | Arabidopsis thaliana | Indirect-family inference | (pqac-00000013, pqac-00000014) | 2023 | https://doi.org/10.3389/fpls.2023.1154431 |
| Quantitative data | ROS imaging/wounding study used DMTU 100 uM and DPI 50 uM; Atcuaoβ mutants lacked wound-induced guard-cell ROS fluorescence, whereas rbohd mainly reduced distal/systemic signal. | Arabidopsis thaliana | Indirect-family inference | (pqac-00000010, pqac-00000012, pqac-00000016) | 2023 | https://doi.org/10.3389/fpls.2023.1154431 |
| Evidence limitation | No retrieved paper in this search directly mentioned UniProt A0A314KPU1, AMO_3, or ORF A4A49_14063 in Nicotiana attenuata; annotation therefore rests on UniProt family/domain assignment plus indirect evidence from plant CuAOs and Nicotiana MPO literature. | Nicotiana attenuata AMO_3 target | Direct for N. attenuata AMO_3 (not available); current evidence is indirect | (pqac-00000002, pqac-00000017) | 2018, 2025 | https://doi.org/10.1007/978-1-4939-7398-9_20 ; https://doi.org/10.3389/fpls.2025.1647622 |


*Table: This table summarizes direct evidence limitations and the strongest indirect evidence from plant CuAO and Nicotiana MPO literature relevant to annotating Nicotiana attenuata AMO_3 (UniProt A0A314KPU1). It is useful for separating family-level biochemical inference from Nicotiana-specific pathway context and from unavailable direct gene-specific evidence.*