| Feature/Claim | Evidence type (genetic, biochemical, cell biology) | Key details/quantitative data | Source (authors year journal) | URL/DOI |
|---|---|---|---|---|
| Verified identity of TUD1 = ELF1 = OsPUB75 in rice | Genetic, sequence/domain annotation | Same rice locus reported as Os03g0232600/LOC_Os03g13010; single-exon ORF 1380 bp encoding a 459 aa PUB-family protein; matches UniProt Q10PI9 aliases and rice organism assignment (pqac-00000004, pqac-00000005, pqac-00000007) | Hu et al. 2013 *PLoS Genetics*; Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.1371/journal.pgen.1003391; https://doi.org/10.4161/psb.27117 |
| Domain architecture: U-box E3 ligase with ARM repeats | Biochemical, sequence analysis | Canonical N-terminal U-box plus six ARM repeats; ΔU-box (Val65–Phe132 deletion) reduces interaction with E2/polyubiquitin and abolishes ligase function; ARM repeats inferred important for substrate recognition/activity (pqac-00000001, pqac-00000005, pqac-00000007) | Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.4161/psb.27117 |
| Functional E3 ubiquitin ligase activity | Biochemical | Purified GST-TUD1/ELF1 showed in vitro ubiquitination activity with E1 and E2; multiple mutant forms (including tud1-1, tud1-3, tud1-4) lacked apparent E3 activity; U-box deletion abolished activity (pqac-00000000, pqac-00000001, pqac-00000005) | Hu et al. 2013 *PLoS Genetics*; Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.1371/journal.pgen.1003391; https://doi.org/10.4161/psb.27117 |
| Subcellular localization | Cell biology | TUD1::sGFP localized predominantly to the plasma membrane in rice protoplasts; figure evidence also shows this localization directly (pqac-00000000, pqac-00000011) | Hu et al. 2013 *PLoS Genetics* | https://doi.org/10.1371/journal.pgen.1003391 |
| Physical interactor: heterotrimeric Gα subunit D1/RGA1 | Biochemical, cell biology, genetics | Interaction shown by BiFC, yeast two-hybrid, and GST pull-down; TUD1 binds both GDP- and GTPγS-bound D1 similarly; tud1 is epistatic to d1, placing TUD1 downstream of D1 in a BR-related G-protein pathway (pqac-00000000, pqac-00000002, pqac-00000006, pqac-00000011) | Hu et al. 2013 *PLoS Genetics* | https://doi.org/10.1371/journal.pgen.1003391 |
| Pathway role in brassinosteroid signaling | Genetics, physiology, expression analysis | Loss-of-function mutants are BR-insensitive in lamina bending assays; BR response tested across 0–1000 ng 24-eBL; tud1 is additive with d61/OsBRI1 but epistatic to d1, supporting a D1-TUD1 branch that overlaps/crosstalks with canonical OsBRI1 signaling (pqac-00000004, pqac-00000006, pqac-00000011) | Hu et al. 2013 *PLoS Genetics*; Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.1371/journal.pgen.1003391; https://doi.org/10.4161/psb.27117 |
| Mutant architecture and grain phenotypes | Genetic, developmental/cell biology | tud1/elf1 mutants are dwarf or semi-dwarf with erect leaves, compact panicles, dark-green leaves, shortened internodes (especially second internode), and short grains; grain length reduced by ~30–44% in tud1 alleles; elf1 plant height ~1/3 of wild type (pqac-00000001, pqac-00000004, pqac-00000006) | Hu et al. 2013 *PLoS Genetics*; Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.1371/journal.pgen.1003391; https://doi.org/10.4161/psb.27117 |
| Cellular basis of phenotype | Cell biology, developmental genetics | Dwarfism attributed mainly to reduced cell proliferation and disorganized cell files; in some tissues failed cell elongation also reported; leaf blade and grain husk cell defects are consistent with BR-growth impairment (pqac-00000000, pqac-00000002) | Hu et al. 2013 *PLoS Genetics* | https://doi.org/10.1371/journal.pgen.1003391 |
| Expression pattern and regulation | Expression analysis | ELF1/TUD1 transcript highest in panicles at flowering, moderate in shoot apices/leaf sheaths/blades/internodes, lowest in roots; slightly decreased by brassinolide; >2× higher in BR-deficient brd1-2 and BR-insensitive d61-3; increased in dark-grown seedlings (pqac-00000001) | Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.4161/psb.27117 |
| Feedback effects on BR pathway outputs | Expression analysis, hormone quantification | In elf1, OsBRI1 mRNA increased ~1.7×; several BR biosynthetic genes increased ~1.5–1.8×; CYP85A1 ~1.8×; bioactive castasterone doubled, consistent with feedback compensation in a BR-signaling-defective background (pqac-00000005) | Sakamoto et al. 2013 *Plant Signaling & Behavior* | https://doi.org/10.4161/psb.27117 |
| Proposed/validated target: GSK2 | Biochemical, genetics, signaling | Mechanistic update reports TUD1 interacts with, ubiquitinates, and promotes degradation of GSK2, a central negative BR-signaling kinase; BR induces TUD1 accumulation, while BRZ suppresses it; BR-induced GSK2 degradation is delayed in tud1 mutants, positioning TUD1 as an integration node between D1- and OsBRI1-mediated BR pathways (pqac-00000003, pqac-00000008, pqac-00000009) | Liu et al. 2025 *Plant Communications*; You et al. 2024 *Molecular Breeding* | https://doi.org/10.1016/j.xplc.2025.101255; https://doi.org/10.1007/s11032-024-01480-x |
| Proposed drought-related target/module note for OsPUB75 | Citation/title-level recent evidence | A 2024 paper title cited in later literature reports “OsPUB75-OsHDA716 mediates deactivation and degradation of OsbZIP46 to negatively regulate drought tolerance in rice”; this is supportive as a recent functional lead but was not directly examined in the gathered primary excerpt, so it should be treated cautiously pending full-paper verification (pqac-00000010) | Sun et al. 2024 *Plant Physiology* (title cited within later paper) | https://doi.org/10.1093/plphys/kiae545 |
| Application and breeding relevance | Review/QTL context, translational interpretation | TUD1 is repeatedly discussed as a grain-size and plant-architecture regulator relevant to breeding for semi-dwarfism/erect leaves; 2024 QTL work contextualizes TUD1 in the ubiquitin-BR-GSK2 module affecting grain shape, and broader rice reviews list TUD1 among potentially useful dwarfing/semi-dwarfing genes (pqac-00000009, pqac-00000006) | You et al. 2024 *Molecular Breeding*; Hu et al. 2013 *PLoS Genetics* | https://doi.org/10.1007/s11032-024-01480-x; https://doi.org/10.1371/journal.pgen.1003391 |


*Table: This table summarizes experimentally supported functional annotation for rice TUD1/ELF1/OsPUB75, including domains, localization, interactors, signaling role, phenotypes, and recent mechanistic updates. It is useful as a compact evidence map for gene function and applied crop-research context.*