FT/florigen (PEBP family) functions - vegetative-to-reproductive phase transition of meristem, regulation of timing of that transition, regulation of flower development and inflorescence development - are conserved across the FT-like phylogenetic group and were propagated to Hd3a by IBA.

SwissProt keyword-derived (SPKW) annotations present in an earlier keyword2GO snapshot but removed from the current GOA release after GOA retired the keyword2GO pipeline for cellular organisms.

For HD3A the keywords "Differentiation" and "Flowering"/"Developmental protein" mapped to GO:0030154 (cell differentiation) and GO:0009908 (flower development); both are over-general / mis-targeted for a mobile flowering-time signal and their removal was reasonable (cell differentiation) or warrants replacement with a regulatory term (flower development).

UniProt subcellular-location mapping assigns Nucleus (SL-0191) and Cytoplasm (SL-0086) to Hd3a, consistent with the cytoplasmic Hd3a-14-3-3 subcomplex and its nuclear FAC.

ARBA models assigned regulation of flower development, inflorescence development, regulation of timing of the vegetative-to-reproductive transition, and photoperiodism (flowering) to Hd3a; these duplicate or parallel the curated IBA/IMP annotations.

Characterizes Arabidopsis FT (the Hd3a ortholog) genetically - FT promotes flowering downstream of CONSTANS and acts antagonistically with TERMINAL FLOWER1 (TFL1); loss of FT delays flowering and FT overexpression causes precocious flowering.

Does not measure phosphatidylethanolamine binding; the ISS GO:0008429 annotation citing this paper is a PEBP-family-namesake inference, not an experimental MF.

Identified Hd3a as an FT-like gene at a heading-date QTL; introduction of Hd3a caused an early-heading phenotype, Hd3a transcript increased under short days, and Hd3a mRNA is up-regulated by Hd1 under SD - Hd3a promotes heading under the control of Hd1.

Establishes the conserved function/regulatory relationship of Hd3a/FT with Hd1/CO between rice (SD plant) and Arabidopsis (LD plant).

Genetically dissected the Hd3 region into two linked heading-date loci, Hd3a and Hd3b; the Kasalath allele at Hd3a promotes heading (flowering) under short-day conditions.

A flowering-time (heading-date) QTL study; provides no inflorescence-morphogenesis characterization.

Demonstrated that the Hd3a protein moves from the leaf to the shoot apical meristem and induces flowering - the key experimental evidence that Hd3a is the rice florigen (a mobile flowering signal).

Hd3a is expressed (protein level) in leaf-blade vascular tissue, stem and the inner region of the SAM, with circadian expression peaking at dawn under SD - consistent with a leaf-to-SAM long-distance signaling role.

Synthesizes the rice florigen literature, concluding Hd3a is the rice ortholog of Arabidopsis FT and a phloem-mobile florigen - synthesized in leaf vascular tissue, transported through the phloem, unloaded near the SAM, and entering the SAM to trigger the vegetative-to-reproductive transition.

Describes Hd3a's molecular mode of action as protein-protein interaction - it is not an enzyme or transporter - forming a cytoplasmic Hd3a-14-3-3 (GF14) subcomplex that becomes nuclear upon OsFD1 co-expression to assemble the florigen activation complex (FAC), which activates floral MADS-box genes OsMADS14/OsMADS15. The Hd3a-14-3-3 interaction is essential.

Documents large flowering-time phenotypes (Hd3a RNAi delays flowering >30 days; Hd3a+RFT1 double suppression prevents flowering up to 300 days) and a steep photoperiod response (Hd3a falls to <1/10 above ~13.5 h day length; a 10-min night break blocks induction); Hd3a acts downstream of Hd1 and Ehd1.