NaODC_candidate_ODC is an ornithine decarboxylase candidate for the polyamine branch that feeds nicotine biosynthesis in Nicotiana attenuata. It catalyzes putrescine formation from ornithine and is a strong candidate for the ODC step in the upstream N-methylpyrrolinium module.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This parent catalytic term is too generic. Reason: GO:0004586 already captures the informative enzymatic chemistry for this accession. |
| GO:0004586 ornithine decarboxylase activity | IEA GO_REF:0000120 | ACCEPT | Summary: This is the core molecular-function annotation for the candidate. Reason: UniProt explicitly identifies ornithine-to-putrescine decarboxylation for this accession. Supporting Evidence: file:NICAT/NaODC_candidate_ODC/NaODC_candidate_ODC-notes.md UniProt curates A0A314KUM9 as ornithine decarboxylase, catalyzing the PLP-dependent conversion of L-ornithine to putrescine and assigning the protein to both putrescine and nicotine biosynthesis. |
| GO:0005737 cytoplasm | IEA GO_REF:0000118 | REMOVE | Summary: Cytoplasmic localization is not the best-supported location for this candidate. Reason: UniProt supports chloroplast/plastid localization instead, so the TreeGrafter cytoplasm inference is not the preferred assignment. Supporting Evidence: file:NICAT/NaODC_candidate_ODC/NaODC_candidate_ODC-uniprot.txt CC -!- SUBCELLULAR LOCATION: Plastid, chloroplast |
| GO:0006596 polyamine biosynthetic process | IEA GO_REF:0000002 | ACCEPT | Summary: This is an appropriate process annotation. Reason: Ornithine decarboxylase provides putrescine to the polyamine pathway. |
| GO:0009507 chloroplast | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: Chloroplast localization should be retained as non-core context. Reason: The location is supported in UniProt, but the more important issue here is pathway membership and paralog ranking. Supporting Evidence: file:NICAT/NaODC_candidate_ODC/NaODC_candidate_ODC-uniprot.txt CC -!- SUBCELLULAR LOCATION: Plastid, chloroplast |
| GO:0033387 putrescine biosynthetic process from arginine, via ornithine | IEA GO_REF:0000120 | MODIFY | Summary: Putrescine biosynthesis is the upstream biological process driven by ODC; the ornithine-route-specific term used here is obsolete and moves to its replacement. Reason: ODC catalyzes the step that converts ornithine to putrescine in the route feeding nicotine biosynthesis. GO:0033387 is obsolete in the GO release 2026-07-26 (replaced_by GO:0009446), so the annotation moves to putrescine biosynthetic process. Proposed replacements: putrescine biosynthetic process Supporting Evidence: file:NICAT/NaODC_candidate_ODC/NaODC_candidate_ODC-notes.md UniProt curates A0A314KUM9 as ornithine decarboxylase, catalyzing the PLP-dependent conversion of L-ornithine to putrescine and assigning the protein to both putrescine and nicotine biosynthesis. |
| GO:0042179 nicotine biosynthetic process | IEA GO_REF:0000041 | ACCEPT | Summary: This is an appropriate pathway annotation for the leading ODC candidate. Reason: The ODC step is part of the upstream module that feeds the N-methylpyrrolinium branch, and this accession is the stronger current ODC mapping. Supporting Evidence: file:NICAT/NaODC_candidate_ODC/NaODC_candidate_ODC-notes.md This accession is therefore a strong NaODC1/NaODC2 candidate, but resolving it against the DCOR paralog still requires evidence beyond current automated pathway annotation. |
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Download this section (compressed HTML)Q: Is this ODC accession the dominant nicotine-feeding paralog in roots, or does the DCOR-related copy make a substantial parallel contribution?
Q: Does chloroplast localization materially constrain where putrescine enters the nicotine pathway in Nicotiana attenuata?
Experiment: Compare ODC and DCOR activity, expression, and root nicotine phenotypes after selective perturbation of each paralog.
Hypothesis: The ODC accession is the major nicotine-feeding ornithine decarboxylase paralog.
Type: comparative genetics and biochemistry
Experiment: Quantify putrescine, N-methylputrescine, and nicotine levels after ODC disruption under topping or herbivory induction.
Hypothesis: Loss of the leading ODC candidate will reduce flux into the pyrrolidine branch.
Type: metabolite profiling after genetic perturbation
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